W3C

Web Services Description Language (WSDL) Version 2.0 Part 1: Core Language

W3C Working Draft 26 March 2007

This version:
    http://www.w3.org/TR/2007/WD-wsdl20-20070326
Latest version:
    http://www.w3.org/TR/wsdl20
Previous version:
    http://www.w3.org/TR/2006/CR-wsdl20-20060327
Editors:
    Roberto Chinnici, Sun Microsystems
    Jean-Jacques Moreau, Canon
    Arthur Ryman, IBM
    Sanjiva Weerawarana, WSO2

This document is also available in these non-normative formats: XHTML with Z
Notation, PDF, PostScript, XML, and plain text.

Copyright © 2007 W3C^® (MIT, ERCIM, Keio), All Rights Reserved. W3C liability,
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Abstract

This document describes the Web Services Description Language Version 2.0 (WSDL
2.0), an XML language for describing Web services. This specification defines
the core language which can be used to describe Web services based on an
abstract model of what the service offers. It also defines the conformance
criteria for documents in this language.

Status of this Document

This section describes the status of this document at the time of its
publication. Other documents may supersede this document. A list of current W3C
publications and the latest revision of this technical report can be found in
the W3C technical reports index at http://www.w3.org/TR/.

This is a W3C Last Call Working of Web Services Description Language (WSDL)
Version 2.0 Part 1: Core Language for review by W3C Members and other
interested parties. It has been produced by the Web Services Description
Working Group, which is part of the W3C Web Services Activity. This document is
published to give an opportunity to the community to review the new namespace
for WSDL 2.0. The Working Group plans to request to move to W3C Proposed
Recommendation shortly after the end of the Last Call period.

As a result of implementer and community feedback the Working Group made a
number of changes since the Candidate Recommendation publication. These changes
include:

  • The namespace of the language specified in the document, and identifiers
    within it, have changed to a shorter, undated form.

  • Numerous consistency and editorial improvements.

  • Improved the granularity and orthogonality of test assertions within the
    document, and between the assertions and the normative schema, by variously
    adding, removing and factoring assertion markup.

  • Clarifications on the visibility of XML Schema element declarations and
    type definitions from WSDL, including the built-in primitive XML Schema
    datatypes.

  • Clarified how the component model is affected when an optional extension
    with required properties is engaged.

  • Described the application/wsdl+xml media type fragment syntax as XPointers;
    defined a canonical form.

  • Added constraints on the appearance of wsdl:input, wsdl:output,
    wsdl:infault, and wsdl:outfault elements for a particular MEP.

  • Added content model controls for faults: #none, #any, #other.

  • Removed wsdl:feature and wsdl:property

Individuals are invited to send feedback on this document to the public
public-ws-desc-comments@w3.org mailing list (public archive) through 15 April
2007.

The Working Group releases a test suite along with an implementation report.

Issues about this document are recorded in the issues list maintained by the
Working Group. A diff-marked version against the previous version of this
document is available.

Publication as a Working Draft does not imply endorsement by the W3C
Membership. This is a draft document and may be updated, replaced or obsoleted
by other documents at any time. It is inappropriate to cite this document as
other than work in progress.

This document is governed by the 24 January 2002 CPP as amended by the W3C
Patent Policy Transition Procedure. W3C maintains a public list of any patent
disclosures made in connection with the deliverables of the group; that page
also includes instructions for disclosing a patent. An individual who has
actual knowledge of a patent which the individual believes contains Essential
Claim(s) must disclose the information in accordance with section 6 of the W3C
Patent Policy.

Table of Contents

1. Introduction
    1.1 Web Service
    1.2 Document Conformance
    1.3 The Meaning of a Service Description
    1.4 Notational Conventions
        1.4.1 RFC 2119 Keywords
        1.4.2 RFC 3986 Namespaces
        1.4.3 XML Schema anyURI
        1.4.4 Prefixes and Namespaces Used in This Specification
        1.4.5 Terms Used in This Specification
        1.4.6 XML Information Set Properties
        1.4.7 WSDL 2.0 Component Model Properties
        1.4.8 Z Notation
        1.4.9 BNF Pseudo-Schemas
        1.4.10 Assertions
2. Component Model
    2.1 Description
        2.1.1 The Description Component
        2.1.2 XML Representation of Description Component
            2.1.2.1 targetNamespace attribute information item
        2.1.3 Mapping Description's XML Representation to Component Properties
    2.2 Interface
        2.2.1 The Interface Component
        2.2.2 XML Representation of Interface Component
            2.2.2.1 name attribute information item with interface [owner
element]
            2.2.2.2 extends attribute information item
            2.2.2.3 styleDefault attribute information item
        2.2.3 Mapping Interface's XML Representation to Component Properties
    2.3 Interface Fault
        2.3.1 The Interface Fault Component
        2.3.2 XML Representation of Interface Fault Component
            2.3.2.1 name attribute information item with fault [owner element]
            2.3.2.2 element attribute information item with fault [owner
element]
        2.3.3 Mapping Interface Fault's XML Representation to Component
Properties
    2.4 Interface Operation
        2.4.1 The Interface Operation Component
            2.4.1.1 Message Exchange Pattern
            2.4.1.2 Operation Style
        2.4.2 XML Representation of Interface Operation Component
            2.4.2.1 name attribute information item with operation [owner
element]
            2.4.2.2 pattern attribute information item with operation [owner
element]
            2.4.2.3 style attribute information item with operation [owner
element]
        2.4.3 Mapping Interface Operation's XML Representation to Component
Properties
    2.5 Interface Message Reference
        2.5.1 The Interface Message Reference Component
        2.5.2 XML Representation of Interface Message Reference Component
            2.5.2.1 messageLabel attribute information item with input or
output [owner element]
            2.5.2.2 element attribute information item with input or output
[owner element]
        2.5.3 Mapping Interface Message Reference's XML Representation to
Component Properties
    2.6 Interface Fault Reference
        2.6.1 The Interface Fault Reference Component
        2.6.2 XML Representation of Interface Fault Reference
            2.6.2.1 ref attribute information item with infault, or outfault
[owner element]
            2.6.2.2 messageLabel attribute information item with infault, or
outfault [owner element]
        2.6.3 Mapping Interface Fault Reference's XML Representation to
Component Properties
    2.7 Binding
        2.7.1 The Binding Component
        2.7.2 XML Representation of Binding Component
            2.7.2.1 name attribute information item with binding [owner
element]
            2.7.2.2 interface attribute information item with binding [owner
element]
            2.7.2.3 type attribute information item with binding [owner
element]
            2.7.2.4 Binding extension elements
        2.7.3 Mapping Binding's XML Representation to Component Properties
    2.8 Binding Fault
        2.8.1 The Binding Fault Component
        2.8.2 XML Representation of Binding Fault Component
            2.8.2.1 ref attribute information item with fault [owner element]
            2.8.2.2 Binding Fault extension elements
        2.8.3 Mapping Binding Fault's XML Representation to Component
Properties
    2.9 Binding Operation
        2.9.1 The Binding Operation Component
        2.9.2 XML Representation of Binding Operation Component
            2.9.2.1 ref attribute information item with operation [owner
element]
            2.9.2.2 Binding Operation extension elements
        2.9.3 Mapping Binding Operation's XML Representation to Component
Properties
    2.10 Binding Message Reference
        2.10.1 The Binding Message Reference Component
        2.10.2 XML Representation of Binding Message Reference Component
            2.10.2.1 messageLabel attribute information item with input or
output [owner element]
            2.10.2.2 Binding Message Reference extension elements
        2.10.3 Mapping Binding Message Reference's XML Representation to
Component Properties
    2.11 Binding Fault Reference
        2.11.1 The Binding Fault Reference Component
        2.11.2 XML Representation of Binding Fault Reference Component
            2.11.2.1 ref attribute information item with infault or outfault
[owner element]
            2.11.2.2 messageLabel attribute information item with infault or
outfault [owner element]
            2.11.2.3 Binding Fault Reference extension elements
        2.11.3 Mapping Binding Fault Reference's XML Representation to
Component Properties
    2.12 Service
        2.12.1 The Service Component
        2.12.2 XML Representation of Service Component
            2.12.2.1 name attribute information item with service [owner
element]
            2.12.2.2 interface attribute information item with service [owner
element]
        2.12.3 Mapping Service's XML Representation to Component Properties
    2.13 Endpoint
        2.13.1 The Endpoint Component
        2.13.2 XML Representation of Endpoint Component
            2.13.2.1 name attribute information item with endpoint [owner
element]
            2.13.2.2 binding attribute information item with endpoint [owner
element]
            2.13.2.3 address attribute information item with endpoint [owner
element]
            2.13.2.4 Endpoint extension elements
        2.13.3 Mapping Endpoint's XML Representation to Component Properties
    2.14 XML Schema 1.0 Simple Types Used in the Component Model
    2.15 Equivalence of Components
    2.16 Symbol Spaces
    2.17 QName resolution
    2.18 Comparing URIs and IRIs
3. Types
    3.1 Using W3C XML Schema Description Language
        3.1.1 Importing XML Schema
            3.1.1.1 namespace attribute information item
            3.1.1.2 schemaLocation attribute information item
        3.1.2 Inlining XML Schema
        3.1.3 References to Element Declarations and Type Definitions
    3.2 Using Other Schema Languages
    3.3 Describing Messages that Refer to Services and Endpoints
        3.3.1 wsdlx:interface attribute information item
        3.3.2 wsdlx:binding attribute information item
        3.3.3 wsdlx:interface and wsdlx:binding Consistency
        3.3.4 Use of wsdlx:interface and wsdlx:binding with xs:anyURI
4. Modularizing WSDL 2.0 descriptions
    4.1 Including Descriptions
        4.1.1 location attribute information item with include [owner element]
    4.2 Importing Descriptions
        4.2.1 namespace attribute information item
        4.2.2 location attribute information item with import [owner element]
    4.3 Extensions
5. Documentation
6. Language Extensibility
    6.1 Element-based Extensibility
        6.1.1 Mandatory extensions
        6.1.2 required attribute information item
    6.2 Attribute-based Extensibility
    6.3 Extensibility Semantics
7. Locating WSDL 2.0 Documents
    7.1 wsdli:wsdlLocation attribute information item
8. Conformance
    8.1 XML Information Set Conformance
9. XML Syntax Summary (Non-Normative)
10. References
    10.1 Normative References
    10.2 Informative References

Appendices

A. The application/wsdl+xml Media Type
    A.1 Registration
    A.2 Fragment Identifiers
        A.2.1 The Description Component
        A.2.2 The Element Declaration Component
        A.2.3 The Type Definition Component
        A.2.4 The Interface Component
        A.2.5 The Interface Fault Component
        A.2.6 The Interface Operation Component
        A.2.7 The Interface Message Reference Component
        A.2.8 The Interface Fault Reference Component
        A.2.9 The Binding Component
        A.2.10 The Binding Fault Component
        A.2.11 The Binding Operation Component
        A.2.12 The Binding Message Reference Component
        A.2.13 The Binding Fault Reference Component
        A.2.14 The Service Component
        A.2.15 The Endpoint Component
        A.2.16 Extension Components
    A.3 Security considerations
B. Acknowledgements (Non-Normative)
C. IRI-References for WSDL 2.0 Components (Non-Normative)
    C.1 WSDL 2.0 IRIs
    C.2 Canonical Form for WSDL 2.0 Component Designators
    C.3 Example
D. Component Summary (Non-Normative)
E. Assertion Summary (Non-Normative)
F. Part 1 Change Log (Non-Normative)
    F.1 WSDL 2.0 Specification Changes

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1. Introduction

Web Services Description Language Version 2.0 (WSDL 2.0) provides a model and
an XML format for describing Web services. WSDL 2.0 enables one to separate the
description of the abstract functionality offered by a service from concrete
details of a service description such as “how” and “where” that functionality
is offered.

This specification defines a language for describing the abstract functionality
of a service as well as a framework for describing the concrete details of a
service description. It also defines the conformance criteria for documents in
this language.

The companion specification, Web Services Description Language (WSDL) Version
2.0 Part 2: Adjuncts [WSDL 2.0 Adjuncts] describes extensions for message
exchange patterns, operation safety, operation styles and binding extensions
(for SOAP [SOAP 1.2 Part 1: Messaging Framework (Second Edition)] and HTTP [
IETF RFC 2616]).

1.1 Web Service

WSDL 2.0 describes a Web service in two fundamental stages: one abstract and
one concrete. Within each stage, the description uses a number of constructs to
promote reusability of the description and to separate independent design
concerns.

At an abstract level, WSDL 2.0 describes a Web service in terms of the messages
it sends and receives; messages are described independent of a specific wire
format using a type system, typically XML Schema.

An operation associates a message exchange pattern with one or more messages. A
message exchange pattern identifies the sequence and cardinality of messages
sent and/or received as well as who they are logically sent to and/or received
from. An interface groups together operations without any commitment to
transport or wire format.

At a concrete level, a binding specifies transport and wire format details for
one or more interfaces. An endpoint associates a network address with a
binding. And finally, a service groups together endpoints that implement a
common interface.

1.2 Document Conformance

An element information item (as defined in [XML Information Set]) whose
namespace name is "http://www.w3.org/ns/wsdl" and whose local part is
description conforms to this specification if it is valid according to the XML
Schema for that element as defined by this specification (http://www.w3.org/
2007/03/wsdl/wsdl20.xsd) and additionally adheres to all the constraints
contained in this specification family and conforms to the specifications of
any extensions contained in it. Such a conformant element information item
constitutes a WSDL 2.0 document.

The definition of the WSDL 2.0 language is based on the XML Information Set [
XML Information Set] but also imposes many semantic constraints over and above
structural conformance to this XML Infoset. In order to precisely describe
these constraints, and as an aid in precisely defining the meaning of each WSDL
2.0 document, the WSDL 2.0 specification defines a component model 2. Component
Model as an additional layer of abstraction above the XML Infoset. Constraints
and meaning are defined in terms of this component model, and the definition of
each component includes a mapping that specifies how values in the component
model are derived from corresponding items in the XML Infoset.

An XML 1.0 document that is valid with respect to the WSDL 2.0 XML Schema and
that maps to a valid WSDL 2.0 Component Model is conformant to the WSDL 2.0
specification.

1.3 The Meaning of a Service Description

A WSDL 2.0 service description indicates how potential clients are intended to
interact with the described service. It represents an assertion that the
described service fully implements and conforms to what the WSDL 2.0 document
describes. For example, as further explained in section 6.1.1 Mandatory
extensions, if the WSDL 2.0 document specifies a particular optional extension,
the functionality implied by that extension is only optional to the client. It
must be supported by the Web service.

A WSDL 2.0 interface describes potential interactions with a Web service, not
required interactions. The declaration of an operation in a WSDL 2.0 interface
is not an assertion that the interaction described by the operation must occur.
Rather it is an assertion that if such an interaction is (somehow) initiated,
then the declared operation describes how that interaction is intended to
occur.

1.4 Notational Conventions

All parts of this specification are normative, with the EXCEPTION of notes,
pseudo-schemas, examples, and sections explicitly marked as “Non-Normative”.

1.4.1 RFC 2119 Keywords

The keywords “MUST”, “MUST NOT”, “REQUIRED”, “SHALL”, “SHALL NOT”, “SHOULD”,
“SHOULD NOT”, “RECOMMENDED”, “MAY”, and “OPTIONAL” in this document are to be
interpreted as described in RFC 2119 [IETF RFC 2119].

1.4.2 RFC 3986 Namespaces

Namespace names of the general form:

  • "http://example.org/..." and

  • "http://example.com/..."

represent application or context-dependent URIs [IETF RFC 3986].

1.4.3 XML Schema anyURI

This specification uses the XML Schema type xs:anyURI (see [XML Schema:
Datatypes]). It is defined so that xs:anyURI values are essentially IRIs (see [
IETF RFC 3987]). The conversion from xs:anyURI values to an actual URI is via
an escaping procedure defined by (see [XLink 1.0]), which is identical in most
respects to IRI Section 3.1 (see [IETF RFC 3987]).

For interoperability, WSDL authors are advised to avoid the US-ASCII
characters: "<", ">", '"', space, "{", "}", "|", "\", "^", and "`", which are
allowed by the xs:anyURI type, but disallowed in IRIs.

1.4.4 Prefixes and Namespaces Used in This Specification

This specification uses predefined namespace prefixes throughout; they are
given in the following list. Note that the choice of any namespace prefix is
arbitrary and not semantically significant (see [XML Namespaces]).

wsdl

    "http://www.w3.org/ns/wsdl"

    Defined by this specification.

wsdli

    "http://www.w3.org/ns/wsdl-instance"

    Defined by this specification 7.1 wsdli:wsdlLocation attribute information
    item.

wsdlx

    "http://www.w3.org/ns/wsdl-extensions"

    Defined by this specification 3.3 Describing Messages that Refer to
    Services and Endpoints.

wrpc

    "http://www.w3.org/ns/wsdl/rpc"

    Defined by WSDL 2.0: Adjuncts [WSDL 2.0 Adjuncts].

wsoap

    "http://www.w3.org/ns/wsdl/soap"

    Defined by WSDL 2.0: Adjuncts [WSDL 2.0 Adjuncts].

whttp

    "http://www.w3.org/ns/wsdl/http"

    Defined by WSDL 2.0: Adjuncts [WSDL 2.0 Adjuncts].

xs

    "http://www.w3.org/2001/XMLSchema"

    Defined in the W3C XML Schema specification [XML Schema: Structures], [XML
    Schema: Datatypes].

xsi

    "http://www.w3.org/2001/XMLSchema-instance"

    Defined in the W3C XML Schema specification [XML Schema: Structures], [XML
    Schema: Datatypes].

1.4.5 Terms Used in This Specification

This section describes the terms and concepts introduced in Part 1 of the WSDL
Version 2.0 specification (this document).

Actual Value

    As in [XML Schema: Structures], the expression "actual value" is used to
    refer to the member of the value space of the simple type definition
    associated with an attribute information item which corresponds to its
    normalized value. This will often be a string, but may also be an integer,
    a boolean, an IRI-reference, etc.

Inlined Schema

    An XML schema that is defined in the xs:types element information item of a
    WSDL 2.0 description. For example, an XML Schema defined in an xs:schema
    element information item 3.1.2 Inlining XML Schema.

1.4.6 XML Information Set Properties

This specification refers to properties in the XML Information Set [XML
Information Set]. Such properties are denoted by square brackets, e.g.
[children], [attributes].

1.4.7 WSDL 2.0 Component Model Properties

This specification defines and refers to properties in the WSDL 2.0 Component
Model 2. Component Model. Such properties are denoted by curly brackets, e.g. {
name}, {interfaces}.

This specification uses a consistent naming convention for component model
properties that refer to components. If a property refers to a required or
optional component, then the property name is the same as the component name.
If a property refers to a set of components, then the property name is the
pluralized form of the component name.

1.4.8 Z Notation

Z Notation [Z Notation Reference Manual] was used in the development of this
specification. Z Notation is a formal specification language that is based on
standard mathematical notation. The Z Notation for this specification has been
verified using the Fuzz 2000 type-checker [Fuzz 2000].

Since Z Notation is not widely known, it is not included the normative version
of this specification. However, it is included in a non-normative version which
allows to dynamically hide and show the Z Notation. Browsers correctly display
the mathematical Unicode characters, provided that the required fonts are
installed. Mathematical fonts for Mozilla Firefox can be downloaded from the
Mozilla Web site.

The Z Notation was used to improve the quality of the normative text that
defines the Component Model, and to help ensure that the test suite covered all
important rules implied by the Component Model. However, the Z Notation is
non-normative, so any conflict between it and the normative text is an error in
the Z Notation. Readers and implementers may nevertheless find the Z Notation
useful in cases where the normative text is unclear.

There are two elements of Z Notation syntax that conflict with the notational
conventions described in the preceding sections. In Z Notation, square brackets
are used to introduce basic sets, e.g. [ID], which conflicts with the use of
square brackets to denote XML Information Set properties 1.4.6 XML Information
Set Properties. Also, in Z Notation, curly brackets are used to denote set
display and set comprehension, e.g. {1, 2, 3}, which conflicts with the use of
curly brackets to denote WSDL 2.0 Component Model properties 1.4.7 WSDL 2.0
Component Model Properties. However, the intended meaning of square and curly
brackets should be clear from their context and this minor notational conflict
should not cause any confusion.

1.4.9 BNF Pseudo-Schemas

Pseudo-schemas are provided for each component, before the description of the
component. They use BNF-style conventions for attributes and elements: "?"
denotes optionality (i.e. zero or one occurrences), "*" denotes zero or more
occurrences, "+" one or more occurrences, "[" and "]" are used to form groups,
and "|" represents choice. Attributes are conventionally assigned a value which
corresponds to their type, as defined in the normative schema. Elements with
simple content are conventionally assigned a value which corresponds to the
type of their content, as defined in the normative schema. Pseudo schemas do
not include extension points for brevity.

<!-- sample pseudo-schema -->
<defined_element
      required_attribute_of_type_string="xs:string"
      optional_attribute_of_type_int="xs:int"? >
  <required_element />
  <optional_element />?
  <one_or_more_of_these_elements />+
  [ <choice_1 /> | <choice_2 /> ]*
</defined_element>

1.4.10 Assertions

Assertions about WSDL 2.0 documents and components that are not enforced by the
normative XML schema for WSDL 2.0 are marked by a dagger symbol (†) at the end
of a sentence. Each assertion has been assigned a unique identifier that
consists of a descriptive textual prefix and a unique numeric suffix. The
numeric suffixes are assigned sequentially and never reused so there may be
gaps in the sequence. The assertion identifiers MAY be used by implementations
of this specification for any purpose, e.g. error reporting.

The assertions and their identifiers are summarized in section E. Assertion
Summary.

2. Component Model

This section describes the conceptual model of WSDL 2.0 as a set of components
with attached properties, which collectively describe a Web service. This model
is called the Component Model of WSDL 2.0. A valid WSDL 2.0 component model is
a set of WSDL 2.0 components and properties that satisfy all the requirements
given in this specification as indicated by keywords whose interpretation is
defined by RFC 2119 [IETF RFC 2119].

Components are typed collections of properties that correspond to different
aspects of Web services. Each subsection herein describes a different type of
component, its defined properties, and its representation as an XML Infoset [
XML Information Set].

Properties are unordered and unique with respect to the component they are
associated with. Individual properties' definitions may constrain their content
(e.g., to a typed value, another component, or a set of typed values or
components), and components may require the presence of a property to be
considered conformant. Such properties are marked as REQUIRED, whereas those
that are not required to be present are marked as OPTIONAL. By convention, when
specifying the mapping rules from the XML Infoset representation of a component
to the component itself, an optional property that is absent in the component
in question is described as being “empty”. Unless otherwise specified, when a
property is identified as being a collection (a set or a list), its value may
be a 0-element (empty) collection. In order to simplify the presentation of the
rules that deal with sets of components, for all OPTIONAL properties whose type
is a set, the absence of such a property from a component MUST be treated as
semantically equivalent to the presence of a property with the same name and
whose value is the empty set. In other words, every OPTIONAL set-valued
property MUST be assumed to have the empty set as its default value, to be used
in case the property is absent.

Component definitions are serializable in XML 1.0 format but are independent of
any particular serialization of the component model. Component definitions use
a subset (see 2.14 XML Schema 1.0 Simple Types Used in the Component Model) of
the simple types defined by the XML Schema 1.0 specification [XML Schema:
Datatypes].

In addition to the direct XML Infoset representation described here, the
component model allows components external to the Infoset through the
mechanisms described in 4. Modularizing WSDL 2.0 descriptions.

A component model can be extracted from a given XML Infoset which conforms to
the XML Schema for WSDL 2.0 by recursively mapping Information Items to their
identified components, starting with the wsdl:description element information
item. This includes the application of the mechanisms described in 4.
Modularizing WSDL 2.0 descriptions.

This document does not specify a means of producing an XML Infoset
representation from a component model instance. In particular, there are in
general many valid ways to modularize a given component model instance into one
or more XML Infosets.

2.1 Description

2.1.1 The Description Component

At the abstract level, the Description component is just a container for two
categories of components: WSDL 2.0 components and type system components.

WSDL 2.0 components are interfaces, bindings and services. Type system
components are element declarations and type definitions.

Type system components describe the constraints on a message's content. By
default, these constraints are expressed in terms of the [XML Information Set],
i.e. they define the [local name], [namespace name], [children] and
[attributes] properties of an element information item. Type systems based upon
other data models are generally accommodated by extensions to WSDL 2.0; see 6.
Language Extensibility. In the case where they define information equivalent to
that of a XML Schema global element declaration, they can be treated as if they
were such a declaration.

This specification does not define the behavior of a WSDL 2.0 document that
uses multiple schema languages for describing type system components
simultaneously.

An Element Declaration component defines the name and content model of an
element information item such as that defined by an XML Schema global element
declaration. It has a {name} property that is the QName of the element
information item and a {system} property that is the namespace IRI of the
extension element information items for the type system, e.g. the namespace of
XML Schema.

A Type Definition component defines the content model of an element information
item such as that defined by an XML Schema global type definition. It has a {
name} property that is the QName of the type and a {system} property that is
the namespace IRI of the extension element information items for the type
system, e.g. the namespace of XML Schema.

Interface, Binding, Service, Element Declaration, and Type Definition
components are directly contained in the Description component and are referred
to as top-level components. The top-level WSDL 2.0 components contain other
components, e.g. Interface Operation and Endpoint, which are referred to as
nested components. Nested components may contain other nested components. The
component that contains a nested component is referred to as the parent of the
nested component. Nested components have a {parent} property that is a
reference to their parent component.

The properties of the Description component are as follows:

  • {interfaces} OPTIONAL. A set of Interface components.

  • {bindings} OPTIONAL. A set of Binding components.

  • {services} OPTIONAL. A set of Service components.

  • {element declarations} OPTIONAL. A set of Element Declaration components.

  • {type definitions} REQUIRED. A set of Type Definition components.

The set of top-level components contained in the Description component
associated with an initial WSDL 2.0 document consists of the components defined
in the initial document, plus the components associated with the WSDL 2.0
documents that the initial document includes, plus the components defined by
other WSDL 2.0 documents in the namespaces that the initial document imports.
The component model makes no distinction between the components that are
defined in the initial document versus those that are defined in the included
documents or imported namespaces. However, any WSDL 2.0 document that contains
component definitions that refer by QName to WSDL 2.0 components that belong to
a different namespace MUST contain a wsdl:import element information item for
that namespace (see 4.2 Importing Descriptions ). Furthermore, all QName
references, whether to the same or to different namespaces must resolve to
components (see 2.17 QName resolution ).

When using the XML Schema language to describe type system components, the
inclusion of Element Declaration components and Type Definition components in a
Description component is governed by the rules in 3.1 Using W3C XML Schema
Description Language.

In addition to WSDL 2.0 components and type system components, additional
extension components MAY be added via extensibility 6. Language Extensibility.
Further, additional properties to WSDL 2.0 and type system components MAY also
be added via extensibility.

2.1.2 XML Representation of Description Component

<description
      targetNamespace="xs:anyURI" >
  <documentation />*
  [ <import /> | <include /> ]*
  <types />?
  [ <interface /> | <binding /> | <service /> ]*
</description>

WSDL 2.0 descriptions are represented in XML by one or more WSDL 2.0
Information Sets (Infosets), that is one or more description element
information items. A WSDL 2.0 Infoset contains representations for a collection
of WSDL 2.0 components that share a common target namespace. A WSDL 2.0 Infoset
that contains one or more wsdl:import element information items 4.2 Importing
Descriptions corresponds to a collection with components drawn from multiple
target namespaces.

The components directly defined or included within a Description component are
said to belong to the same target namespace. The target namespace therefore
groups a set of related component definitions and represents an unambiguous
name for the intended semantics of the collection of components. The value of
the targetNamespace attribute information item SHOULD be dereferencable.^† It
SHOULD resolve to a human or machine processable document that directly or
indirectly defines the intended semantics of those components.^† It MAY resolve
to a WSDL 2.0 document that provides service description information for that
namespace.^†

If a WSDL 2.0 document is split into multiple WSDL 2.0 documents (which may be
combined as needed via 4.1 Including Descriptions), then the targetNamespace
attribute information item SHOULD resolve to a master WSDL 2.0 document that
includes all the WSDL 2.0 documents needed for that service description.^† This
approach enables the WSDL 2.0 component designator fragment identifiers to be
properly resolved.

Components that belong to imported namespaces have different target namespace
values than that of the importing WSDL 2.0 document. Thus importing is the
mechanism to use components from one namespace in the definition of components
from another namespace.

Note that each WSDL 2.0 document or type system component of the same kind must
be uniquely identified by its qualified name. That is, if two distinct
components of the same kind (Interface, Binding, etc.) are in the same target
namespace, then their QNames MUST be unique. However, different kinds of
components (e.g., an Interface component and a Binding component) MAY have the
same QName. Thus, QNames of components must be unique within the space of those
components in a given target namespace.

The description element information item has the following Infoset properties:

  • A [local name] of description.

  • A [namespace name] of "http://www.w3.org/ns/wsdl".

  • One or more attribute information items amongst its [attributes] as
    follows:

      □ A REQUIRED targetNamespace attribute information item as described
        below in 2.1.2.1 targetNamespace attribute information item.

      □ Zero or more namespace qualified attribute information items whose
        [namespace name] is NOT "http://www.w3.org/ns/wsdl".

  • Zero or more element information items amongst its [children], in order as
    follows:^†

     1. Zero or more documentation element information items (see 5.
        Documentation).

     2. Zero or more element information items from among the following, in any
        order:

          ☆ Zero or more include element information items (see 4.1 Including
            Descriptions)

          ☆ Zero or more import element information items (see 4.2 Importing
            Descriptions)

          ☆ Zero or more namespace-qualified element information items whose
            [namespace name] is NOT "http://www.w3.org/ns/wsdl".

     3. An OPTIONAL types element information item (see 3. Types).

     4. Zero or more element information items from among the following, in any
        order:

          ☆ interface element information items (see 2.2.2 XML Representation
            of Interface Component).

          ☆ binding element information items (see 2.7.2 XML Representation of
            Binding Component).

          ☆ service element information items (see 2.12.2 XML Representation of
            Service Component).

          ☆ Zero or more namespace-qualified element information items whose
            [namespace name] is NOT "http://www.w3.org/ns/wsdl".

2.1.2.1 targetNamespace attribute information item

The targetNamespace attribute information item defines the namespace
affiliation of top-level components defined in this description element
information item. Interface, Binding and Service are top-level components.

The targetNamespace attribute information item has the following Infoset
properties:

  • A [local name] of targetNamespace

  • A [namespace name] which has no value

The type of the targetNamespace attribute information item is xs:anyURI. Its
value MUST be an absolute IRI (see [IETF RFC 3987]) and should be
dereferencable.^†

2.1.3 Mapping Description's XML Representation to Component Properties

The mapping from the XML Representation of the description element information
item (see 2.1.2 XML Representation of Description Component) to the properties
of the Description component is described in Table 2-1.

Table 2-1. Mapping from XML Representation to Description Component Properties
┌─────────────┬───────────────────────────────────────────────────────────────┐
│  Property   │                             Value                             │
├─────────────┼───────────────────────────────────────────────────────────────┤
│             │The set of Interface components corresponding to all the       │
│             │interface element information items in the [children] of the   │
│{interfaces} │description element information item, if any, plus any included│
│             │(via wsdl:include) or imported (via wsdl:import) Interface     │
│             │components (see 4. Modularizing WSDL 2.0 descriptions).        │
├─────────────┼───────────────────────────────────────────────────────────────┤
│             │The set of Binding components corresponding to all the binding │
│             │element information items in the [children] of the description │
│{bindings}   │element information item, if any, plus any included (via       │
│             │wsdl:include) or imported (via wsdl:import) Binding components │
│             │(see 4. Modularizing WSDL 2.0 descriptions).                   │
├─────────────┼───────────────────────────────────────────────────────────────┤
│             │The set of Service components corresponding to all the service │
│             │element information items in the [children] of the description │
│{services}   │element information item, if any, plus any included (via       │
│             │wsdl:include) or imported (via wsdl:import) Service components │
│             │(see 4. Modularizing WSDL 2.0 descriptions).                   │
├─────────────┼───────────────────────────────────────────────────────────────┤
│             │The set of Element Declaration components corresponding to all │
│             │the element declarations defined as descendants of the types   │
│             │element information item, if any, plus any included (via       │
│             │xs:include) or imported (via xs:import) Element Declaration    │
│{element     │components. At a minimum this will include all the global      │
│declarations}│element declarations defined by XML Schema element element     │
│             │information items. It MAY also include any declarations from   │
│             │some other type system which describes the [local name],       │
│             │[namespace name], [attributes] and [children] properties of an │
│             │element information item. Each XML Schema element declaration  │
│             │MUST have a unique QName.^†                                    │
├─────────────┼───────────────────────────────────────────────────────────────┤
│             │The set of Type Definition components corresponding to all the │
│             │type definitions defined as descendants of the types element   │
│             │information item, if any, plus any included (via xs:include) or│
│             │imported (via xs:import) Type Definition components. In        │
│             │addition, the built-in datatypes defined by XML Schema Part 2: │
│             │Datatypes Second Edition [XML Schema: Datatypes], namely the   │
│             │nineteen primitive datatypes xs:string, xs:boolean, xs:decimal,│
│             │xs:float, xs:double, xs:duration, xs:dateTime, xs:time,        │
│             │xs:date, xs:gYearMonth, xs:gYear, xs:gMonthDay, xs:gDay,       │
│{type        │xs:gMonth, xs:hexBinary, xs:base64, xs:Binary, xs:anyURI,      │
│definitions} │xs:QName, xs:NOTATION, and the twenty-five derived datatypes   │
│             │xs:normalizedString, xs:token, xs:language, xs:NMTOKEN,        │
│             │xs:NMTOKENS, xs:Name, xs:NCName, xs:ID, xs:IDREF, xs:IDREFS,   │
│             │xs:ENTITY, xs:ENTITIES, xs:integer, xs:nonPositiveInteger,     │
│             │xs:negativeInteger, xs:long, xs:int, xs:short, xs:byte,        │
│             │xs:nonNegativeInteger, xs:unsignedLong, xs:unsignedInt,        │
│             │xs:unsignedShort, xs:unsignedByte, xs:positiveInteger. The set │
│             │MAY also include any definitions from some other type system   │
│             │which describes the [attributes] and [children] properties of  │
│             │an element information item. Each XML Schema type definition   │
│             │MUST have a unique QName.^†                                    │
└─────────────┴───────────────────────────────────────────────────────────────┘


2.2 Interface

2.2.1 The Interface Component

An Interface component describes sequences of messages that a service sends and
/or receives. It does this by grouping related messages into operations. An
operation is a sequence of input and output messages, and an interface is a set
of operations.

An interface can optionally extend one or more other interfaces. To avoid
circular definitions, an interface MUST NOT appear as an element of the set of
interfaces it extends, either directly or indirectly. ^† The set of operations
available in an interface includes all the operations defined by the interfaces
it extends directly or indirectly, together with any operations it directly
defines. The operations directly defined on an interface are referred to as the
declared operations of the interface. In the process, operation components that
are equivalent per 2.15 Equivalence of Components are treated as one single
component. The interface extension mechanism behaves in a similar way for all
other components that can be defined inside an interface, namely Interface
Fault components.

Interfaces are named constructs and can be referred to by QName (see 2.17 QName
resolution). For instance, Binding components refer to interfaces in this way.

The properties of the Interface component are as follows:

  • {name} REQUIRED. An xs:QName.

  • {extended interfaces} OPTIONAL. A set of declared Interface components
    which this interface extends.

  • {interface faults} OPTIONAL. The set of declared Interface Fault
    components. Note that the namespace name of the {name} property of each
    Interface Fault in this set is the same as the namespace name of the {name}
    property of this Interface component.

  • {interface operations} OPTIONAL. A set of declared Interface Operation
    components. Note that the namespace name of the {name} property of each
    Interface Operation in this set is the same as the namespace name of the {
    name} property of this Interface component.

For each Interface component in the {interfaces} property of a Description
component, the {name} property MUST be unique.^†

2.2.2 XML Representation of Interface Component

<description>
  <interface
        name="xs:NCName"
        extends="list of xs:QName"?
        styleDefault="list of xs:anyURI"? >
    <documentation />*
    [ <fault /> | <operation /> ]*
  </interface>
</description>

The XML representation for an Interface component is an element information
item with the following Infoset properties:

  • A [local name] of interface

  • A [namespace name] of "http://www.w3.org/ns/wsdl"

  • One or more attribute information items amongst its [attributes] as
    follows:

      □ A REQUIRED name attribute information item as described below in
        2.2.2.1 name attribute information item with interface [owner element].

      □ An OPTIONAL extends attribute information item as described below in
        2.2.2.2 extends attribute information item.

      □ An OPTIONAL styleDefault attribute information item as described below
        in 2.2.2.3 styleDefault attribute information item.

      □ Zero or more namespace qualified attribute information items whose
        [namespace name] is NOT "http://www.w3.org/ns/wsdl".

  • Zero or more element information items amongst its [children], in order, as
    follows:

     1. Zero or more documentation element information items (see 5.
        Documentation).

     2. Zero or more element information items from among the following, in any
        order:

          ☆ Zero or more fault element information items 2.3.2 XML
            Representation of Interface Fault Component.

          ☆ Zero or more operation element information items 2.4.2 XML
            Representation of Interface Operation Component.

          ☆ Zero or more namespace-qualified element information items whose
            [namespace name] is NOT "http://www.w3.org/ns/wsdl".

2.2.2.1 name attribute information item with interface [owner element]

The name attribute information item together with the targetNamespace attribute
information item of the [parent] description element information item forms the
QName of the interface.

The name attribute information item has the following Infoset properties:

  • A [local name] of name

  • A [namespace name] which has no value

The type of the name attribute information item is xs:NCName.

2.2.2.2 extends attribute information item

The extends attribute information item lists the interfaces that this interface
derives from.

The extends attribute information item has the following Infoset properties:

  • A [local name] of extends

  • A [namespace name] which has no value

The type of the extends attribute information item is a whitespace-separated
list of xs:QName.

The list of xs:QName in an extends attribute information item MUST NOT contain
duplicates.^†

2.2.2.3 styleDefault attribute information item

The styleDefault attribute information item indicates the default style (see
2.4.1.2 Operation Style) used to construct the {element declaration} properties
of {interface message references} of all operations contained within the [owner
element] interface.

The styleDefault attribute information item has the following Infoset
properties:

  • A [local name] of styleDefault.

  • A [namespace name] which has no value.

The type of the styleDefault attribute information item is list of xs:anyURI.
Its value, if present, MUST contain absolute IRIs (see [IETF RFC 3987]).^†

2.2.3 Mapping Interface's XML Representation to Component Properties

The mapping from the XML Representation of the interface element information
item (see 2.2.2 XML Representation of Interface Component) to the properties of
the Interface component is as described in Table 2-2.

 Table 2-2. Mapping from XML Representation to Interface Component Properties
┌───────────┬─────────────────────────────────────────────────────────────────┐
│ Property  │                              Value                              │
├───────────┼─────────────────────────────────────────────────────────────────┤
│           │The QName whose local name is actual value of the name attribute │
│{name}     │information item and whose namespace name is the actual value of │
│           │the targetNamespace attribute information item of the [parent]   │
│           │description element information item                             │
├───────────┼─────────────────────────────────────────────────────────────────┤
│{extended  │The set of Interface components resolved to by the values in the │
│interfaces}│extends attribute information item, if any (see 2.17 QName       │
│           │resolution).                                                     │
├───────────┼─────────────────────────────────────────────────────────────────┤
│{interface │The set of Interface Fault components corresponding to the fault │
│faults}    │element information items in [children], if any.                 │
├───────────┼─────────────────────────────────────────────────────────────────┤
│{interface │The set of Interface Operation components corresponding to the   │
│operations}│operation element information items in [children], if any.       │
└───────────┴─────────────────────────────────────────────────────────────────┘


Recall that, per 2.2.1 The Interface Component, the Interface components in the
{extended interfaces} property of a given Interface component MUST NOT contain
that Interface component in any of their {extended interfaces} properties, that
is to say, recursive extension of interfaces is disallowed.

2.3 Interface Fault

2.3.1 The Interface Fault Component

A fault is an event that occurs during the execution of a message exchange that
disrupts the normal flow of messages.

A fault is typically raised when a party is unable to communicate an error
condition inside the normal message flow, or a party wishes to terminate a
message exchange. A fault message may be used to communicate out of band
information such as the reason for the error, the origin of the fault, as well
as other informal diagnostics such as a program stack trace.

An Interface Fault component describes a fault that MAY occur during invocation
of an operation of the interface. The Interface Fault component declares an
abstract fault by naming it and indicating the contents of the fault message.
When and how the fault message flows is indicated by the Interface Operation
component.

The Interface Fault component provides a clear mechanism to name and describe
the set of faults an interface may generate. This allows operations to easily
identify the individual faults they may generate by name. This mechanism allows
the ready identification of the same fault occurring across multiple operations
and referenced in multiple bindings as well as reducing duplication of
description for an individual fault.

Faults other than the ones described in the Interface component may also be
generated at run-time, i.e. faults are an open set. The Interface component
describes faults that have application level semantics, i.e. that the client or
service is expected to handle, and potentially recover from, as part of the
application processing logic. For example, an Interface component that accepts
a credit card number may describe faults that indicate the credit card number
is invalid, has been reported stolen, or has expired. The Interface component
does not describe general system faults such as network failures, out of memory
conditions, out of disk space conditions, invalid message formats, etc.,
although these faults may be generated as part of the message exchange. Such
general system faults can reasonably be expected to occur in any message
exchange and explicitly describing them in an Interface component is therefore
uninformative.

The properties of the Interface Fault component are as follows:

  • {name} REQUIRED. An xs:QName.

  • {message content model} REQUIRED. An xs:token with one of the values #any,
    #none, #other, or #element.^† A value of #any indicates that the fault
    content is any single element. A value of #none indicates there is no fault
    content. A value of #other indicates that the fault content is described by
    some other extension property that references a declaration in a non-XML
    extension type system. A value of #element indicates that the fault
    consists of a single element described by the global element declaration
    referenced by the {element declaration} property. This property is used
    only when the fault is described using an XML-based data model.

  • {element declaration} OPTIONAL. A reference to an Element Declaration
    component in the {element declarations} property of the Description
    component. This element represents the content or “payload” of the fault.
    When the {message content model} property has the value #any or #none the {
    element declaration} property MUST be empty.^†

  • {parent} REQUIRED. The Interface component that contains this component in
    its {interface faults} property.

For each Interface Fault component in the {interface faults} property of an
Interface component, the {name} property must be unique. Note that this
constraint is enforced by the normative WSDL 2.0 XML schema.

Interface Fault components are uniquely identified by the QName of the
enclosing Interface component and QName of the Interface Fault component
itself.

Note:

Despite having a {name} property, Interface Fault components cannot be
identified solely by their QName. Indeed, two Interface components whose {name}
property value has the same namespace name, but different local names, can
contain Interface Fault components with the same {name} property value. Thus,
the {name} property of Interface Fault component is not sufficient to form the
unique identity of an Interface Fault component. A method for uniquely
identifying components is defined in A.2 Fragment Identifiers. See A.2.5 The
Interface Fault Component for the definition of the fragment identifier for the
Interface Fault component.

In cases where, due to an interface extending one or more other interfaces, two
or more Interface Fault components have the same value for their {name}
property, then the component models of those Interface Fault components MUST be
equivalent (see 2.15 Equivalence of Components). ^† If the Interface Fault
components are equivalent then they are considered to collapse into a single
component. Within the same Interface component, if two Interface Fault
components are not equivalent then their {name} properties MUST NOT be equal.

Note that, due to the above rules, if two interfaces that have the same value
for the namespace name of their {name} property also have one or more faults
that have the same value for their {name} property, then those two interfaces
cannot both form part of the derivation chain of a derived interface unless
those faults are the same fault.

For the above reason, it is considered good practice to ensure, where
necessary, that the local name of the {name} property of Interface Fault
components within a namespace SHOULD be unique, thus allowing such derivation
to occur without inadvertent error.^†

If a type system NOT based on the XML Infoset [XML Information Set] is in use
(as considered in 3.2 Using Other Schema Languages) then additional properties
would need to be added to the Interface Fault component (along with extension
attributes to its XML representation) to allow associating such message types
with the message reference.

2.3.2 XML Representation of Interface Fault Component

<description>
  <interface>
    <fault
          name="xs:NCName"
          element="union of xs:QName, xs:token"? >
      <documentation />*
    </fault>
  </interface>
</description>

The XML representation for an Interface Fault component is an element
information item with the following Infoset properties:

  • A [local name] of fault

  • A [namespace name] of "http://www.w3.org/ns/wsdl"

  • One or more attribute information items amongst its [attributes] as
    follows:

      □ A REQUIRED name attribute information item as described below in
        2.3.2.1 name attribute information item with fault [owner element].

      □ An OPTIONAL element attribute information item as described below in
        2.3.2.2 element attribute information item with fault [owner element].

      □ Zero or more namespace qualified attribute information items whose
        [namespace name] is NOT "http://www.w3.org/ns/wsdl".

  • Zero or more element information item amongst its [children], in order, as
    follows:

     1. Zero or more documentation element information items (see 5.
        Documentation).

     2. Zero or more namespace-qualified element information item s whose
        [namespace name] is NOT " http://www.w3.org/ns/wsdl " .

2.3.2.1 name attribute information item with fault [owner element]

The name attribute information item identifies a given fault element
information item inside a given interface element information item.

The name attribute information item has the following Infoset properties:

  • A [local name] of name

  • A [namespace name] which has no value

The type of the name attribute information item is xs:NCName.

2.3.2.2 element attribute information item with fault [owner element]

The element attribute information item refers, by QName, to an Element
Declaration component.

The element attribute information item has the following Infoset properties:

  • A [local name] of element.

  • A [namespace name] which has no value.

The type of the element attribute information item is a union of xs:QName and
xs:token where the allowed token values are #any, #none, or #other.

2.3.3 Mapping Interface Fault's XML Representation to Component Properties

The mapping from the XML Representation of the fault element information item
(see 2.3.2 XML Representation of Interface Fault Component) to the properties
of the Interface Fault component is as described in Table 2-3.

    Table 2-3. Mapping from XML Representation to Interface Fault Component
                                  Properties
┌────────────┬────────────────────────────────────────────────────────────────┐
│  Property  │                             Value                              │
├────────────┼────────────────────────────────────────────────────────────────┤
│            │The QName whose local name is the actual value of the name      │
│            │attribute information item. and whose namespace name is the     │
│{name}      │actual value of the targetNamespace attribute information item  │
│            │of the [parent] description element information item of the     │
│            │[parent] interface element information item.                    │
├────────────┼────────────────────────────────────────────────────────────────┤
│{message    │If the element attribute information item is present and its    │
│content     │value is a QName, then #element; otherwise the actual value of  │
│model}      │the element attribute information item, if any; otherwise #other│
│            │.                                                               │
├────────────┼────────────────────────────────────────────────────────────────┤
│            │If the element attribute information item is present and its    │
│            │value is a QName, then the Element Declaration component from   │
│            │the {element declarations} property of the Description component│
│{element    │resolved to by the value of the element attribute information   │
│declaration}│item (see 2.17 QName resolution); otherwise empty. If the       │
│            │element attribute information item has a value, then it MUST    │
│            │resolve to an Element Declaration component from the {element   │
│            │declarations} property of the Description component.^†          │
├────────────┼────────────────────────────────────────────────────────────────┤
│{parent}    │The Interface component corresponding to the interface element  │
│            │information item in [parent].                                   │
└────────────┴────────────────────────────────────────────────────────────────┘


2.4 Interface Operation

2.4.1 The Interface Operation Component

An Interface Operation component describes an operation that a given interface
supports. An operation is an interaction with the service consisting of a set
of (ordinary and fault) messages exchanged between the service and the other
parties involved in the interaction. The sequencing and cardinality of the
messages involved in a particular interaction is governed by the message
exchange pattern used by the operation (see {message exchange pattern}
property).

A message exchange pattern defines placeholders for messages, the participants
in the pattern (i.e., the sources and sinks of the messages), and the
cardinality and sequencing of messages exchanged by the participants. The
message placeholders are associated with specific message types by the
operation that uses the pattern by means of message and fault references (see {
interface message references} and {interface fault references} properties). The
service whose operation is using the pattern becomes one of the participants of
the pattern. This specification does not define a machine understandable
language for defining message exchange patterns, nor does it define any
specific patterns. The companion specification, [WSDL 2.0 Adjuncts] defines a
set of such patterns and defines identifying IRIs any of which MAY be used as
the value of the {message exchange pattern} property.

The properties of the Interface Operation component are as follows:

  • {name} REQUIRED. An xs:QName.

  • {message exchange pattern} REQUIRED. An xs:anyURI identifying the message
    exchange pattern used by the operation. This xs:anyURI MUST be an absolute
    IRI (see [IETF RFC 3987]).^†

  • {interface message references} OPTIONAL. A set of Interface Message
    Reference components for the ordinary messages the operation accepts or
    sends.

  • {interface fault references} OPTIONAL. A set of Interface Fault Reference
    components for the fault messages the operation accepts or sends.

  • {style} OPTIONAL. A set of xs:anyURIs identifying the rules that were used
    to construct the {element declaration} properties of {interface message
    references}. (See 2.4.1.2 Operation Style.) These xs:anyURIs MUST be
    absolute IRIs (see [IETF RFC 3986]).^†

  • {parent} REQUIRED. The Interface component that contains this component in
    its {interface operations} property.

For each Interface Operation component in the {interface operations} property
of an Interface component, the {name} property MUST be unique. Note that this
constraint is enforced by the normative WSDL 2.0 XML schema.

Interface Operation components are uniquely identified by the QName of the
enclosing Interface component and QName of the Interface Operation component
itself.

Note:

Despite having a {name} property, Interface Operation components cannot be
identified solely by their QName. Indeed, two Interface components whose {name}
property value has the same namespace name, but different local names, can
contain Interface Operation components with the same {name} property value.
Thus, the {name} property of Interface Operation components is not sufficient
to form the unique identity of an Interface Operation component. A method for
uniquely identifying components is defined in A.2 Fragment Identifiers . See
A.2.6 The Interface Operation Component for the definition of the fragment
identifier for the Interface Operation component.

In cases where, due to an interface extending one or more other interfaces, two
or more Interface Operation components have the same value for their {name}
property, then the component models of those Interface Operation components
MUST be equivalent (see 2.15 Equivalence of Components).^† If the Interface
Operation components are equivalent then they are considered to collapse into a
single component. Within the same Interface component, if two Interface
Operation components are not equivalent then their {name} properties MUST NOT
be equal.

Note that, due to the above rules, if two interfaces that have the same value
for the namespace name of their {name} property also have one or more
operations that have the same value for their {name} property, then those two
interfaces cannot both form part of the derivation chain of a derived interface
unless those operations are the same operation.

For the above reason, it is considered good practice to ensure, where
necessary, that the {name} property of Interface Operation components within a
namespace SHOULD be unique, thus allowing such derivation to occur without
inadvertent error.^†

More than one Interface Fault Reference component in the {interface fault
references} property of an Interface Operation component may refer to the same
message label. In that case, the listed fault types define alternative fault
messages. This allows one to indicate that there is more than one type of fault
that is related to that message.

2.4.1.1 Message Exchange Pattern

This section describes some aspects of message exchange patterns in more
detail. Refer to the Web Services Description Language (WSDL) Version 2.0 Part
2: Adjuncts specification [WSDL 2.0 Adjuncts] for a complete discussion of the
semantics of message exchange patterns in general, as well as the definitions
of the message exchange patterns that are predefined by WSDL 2.0.

A placeholder message is a template for an actual message as described by an
Interface Message Reference component. Although a placeholder message is not
itself a component, it is useful to regard it as having both a {message label}
and a {direction} property which define the values of the actual Interface
Message Reference component that corresponds to it. A placeholder message is
also associated with some node that exchanges the message with the service.
Furthermore, a placeholder message may be designated as optional in the
exchange.

A fault propagation ruleset specifies the relation between the Interface Fault
Reference and Interface Message Reference components of an Interface Operation
component. The Web Services Description Language (WSDL) Version 2.0 Part 2:
Adjuncts specification [WSDL 2.0 Adjuncts] defines three fault propagation
rulesets which we will refer to as fault-replaces-message,
message-triggers-fault, and no-faults. These three fault propagation rulesets
are used by the predefined message exchange patterns defined in [WSDL 2.0
Adjuncts]. Other message exchange patterns can define additional fault
propagation rulesets.

A message exchange pattern is a template for the exchange of one or more
messages, and their associated faults, between the service and one or more
other nodes as described by an Interface Operation component. The service and
the other nodes are referred to as the participants in the exchange. More
specifically, a message exchange pattern consists of a sequence of one or more
placeholder messages. Each placeholder message within this sequence is uniquely
identified by its {message label} property. A message exchange pattern is
itself uniquely identified by an absolute IRI, which is used as the value of
the {message exchange pattern} property of the Interface Operation component,
and which specifies the fault propagation ruleset that its faults obey.^†

2.4.1.2 Operation Style

An operation style specifies additional information about an operation. For
example, an operation style may define structural constraints on the element
declarations of the interface message reference or interface fault components
used by the operation. This additional information in no way affects the
messages and faults exchanged with the service and it can therefore be safely
ignored in that context. However, the additional information can be used for
other purposes, for example, improved code generation. The {style} property of
the Interface Operation component contains a set of zero or more IRIs that
identify operation styles. An Interface Operation component MUST satisfy the
specification defined by each operation style identified by its {style}
property. ^† If no Interface Operation component can simultaneously satisfy all
of the styles, the document is invalid.

If the {style} property of an Interface Operation component does have a value,
then that value (a set of IRIs) specifies the rules that were used to define
the element declarations (or other properties that define the message and fault
contents; see 3.2 Using Other Schema Languages) of the Interface Message
Reference or Interface Fault components used by the operation. Although a given
operation style has the ability to constrain all input and output messages and
faults of an operation, it MAY choose to constrain any combination thereof,
e.g. only the messages, or only the inputs.

Please refer to the Web Services Description Language (WSDL) Version 2.0 Part
2: Adjuncts specification [WSDL 2.0 Adjuncts] for particular operation style
definitions.

2.4.2 XML Representation of Interface Operation Component

<description>
  <interface>
    <operation
          name="xs:NCName"
          pattern="xs:anyURI"?
          style="list of xs:anyURI"? >
      <documentation />*
      [ <input /> | <output /> | <infault /> | <outfault /> ]*
    </operation>
  </interface>
</description>

The XML representation for an Interface Operation component is an element
information item with the following Infoset properties:

  • A [local name] of operation

  • A [namespace name] of "http://www.w3.org/ns/wsdl"

  • Two or more attribute information items amongst its [attributes] as
    follows:

      □ A REQUIRED name attribute information item as described below in
        2.4.2.1 name attribute information item with operation [owner element].

      □ An OPTIONAL pattern attribute information item as described below in
        2.4.2.2 pattern attribute information item with operation [owner
        element].

      □ An OPTIONAL style attribute information item as described below in
        2.4.2.3 style attribute information item with operation [owner element]
        .

      □ Zero or more namespace qualified attribute information items whose
        [namespace name] is NOT "http://www.w3.org/ns/wsdl".

  • One or more element information item amongst its [children], in order, as
    follows:

     1. Zero or more documentation element information items (see 5.
        Documentation).

     2. One or more element information items from among the following, in any
        order:

          ☆ One or more element information items from among the following, in
            any order:

              ○ Zero or more input element information items (see 2.5.2 XML
                Representation of Interface Message Reference Component).

              ○ Zero or more output element information items (see 2.5.2 XML
                Representation of Interface Message Reference Component).

              ○ Zero or more infault element information items (see 2.6.2 XML
                Representation of Interface Fault Reference).

              ○ Zero or more outfault element information items (see 2.6.2 XML
                Representation of Interface Fault Reference).

          ☆ Zero or more namespace-qualified element information items whose
            [namespace name] is NOT "http://www.w3.org/ns/wsdl".

2.4.2.1 name attribute information item with operation [owner element]

The name attribute information item identifies a given operation element
information item inside a given interface element information item.

The name attribute information item has the following Infoset properties:

  • A [local name] of name

  • A [namespace name] which has no value

The type of the name attribute information item is xs:NCName.

2.4.2.2 pattern attribute information item with operation [owner element]

The pattern attribute information item identifies the message exchange pattern
a given operation uses.

The pattern attribute information item has the following Infoset properties:

  • A [local name] of pattern

  • A [namespace name] which has no value

The type of the pattern attribute information item is xs:anyURI. Note that its
value must be an absolute IRI (see [IETF RFC 3987]).

2.4.2.3 style attribute information item with operation [owner element]

The style attribute information item indicates the rules that were used to
construct the {element declaration} properties of the Interface Message
Reference components which are members of the {interface message references}
property of the [owner element] operation.

The style attribute information item has the following Infoset properties:

  • A [local name] of style

  • A [namespace name] which has no value

The type of the style attribute information item is list of xs:anyURI. Note
that its value must be an absolute IRI (see [IETF RFC 3987]).

2.4.3 Mapping Interface Operation's XML Representation to Component Properties

The mapping from the XML Representation of the operation element information
item (see 2.4.2 XML Representation of Interface Operation Component) to the
properties of the Interface Operation component (see 2.4.1 The Interface
Operation Component) is as described in Table 2-4.

  Table 2-4. Mapping from XML Representation to Interface Operation Component
                                  Properties
┌───────────┬─────────────────────────────────────────────────────────────────┐
│ Property  │                              Value                              │
├───────────┼─────────────────────────────────────────────────────────────────┤
│           │The QName whose local name is the actual value of the name       │
│           │attribute information item and whose namespace name is the actual│
│{name}     │value of the targetNamespace attribute information item of the   │
│           │[parent] description element information item of the [parent]    │
│           │interface element information item.                              │
├───────────┼─────────────────────────────────────────────────────────────────┤
│{message   │The actual value of the pattern attribute information item;      │
│exchange   │otherwise 'http://www.w3.org/ns/wsdl/in-out'.                    │
│pattern}   │                                                                 │
├───────────┼─────────────────────────────────────────────────────────────────┤
│{interface │The set of message references corresponding to the input and     │
│message    │output element information items in [children], if any.          │
│references}│                                                                 │
├───────────┼─────────────────────────────────────────────────────────────────┤
│{interface │The set of interface fault references corresponding to the       │
│fault      │infault and outfault element information items in [children], if │
│references}│any.                                                             │
├───────────┼─────────────────────────────────────────────────────────────────┤
│           │The set containing the IRIs in the actual value of the style     │
│           │attribute information item, if present; otherwise the set        │
│{style}    │containing the IRIs in the actual value of the styleDefault      │
│           │attribute information item of the [parent] interface element     │
│           │information item, if present; otherwise empty.                   │
├───────────┼─────────────────────────────────────────────────────────────────┤
│{parent}   │The Interface component corresponding to the interface element   │
│           │information item in [parent].                                    │
└───────────┴─────────────────────────────────────────────────────────────────┘


2.5 Interface Message Reference

2.5.1 The Interface Message Reference Component

An Interface Message Reference component defines the content, or payload, of a
message exchanged in an operation. By default, the message content is defined
by an XML-based type system such as XML Schema. Other type systems may be used
via the WSDL 2.0 type system extension mechanism.

A message exchange pattern defines a set of placeholder messages that
participate in the pattern and assigns them unique message labels within the
pattern (e.g. 'In', 'Out'). The purpose of an Interface Message Reference
component is to associate an actual message element (XML element declaration or
some other declaration (see 3.2 Using Other Schema Languages)) with a message
in the pattern, as identified by its message label. Later, when the message
exchange pattern is instantiated, messages corresponding to that particular
label will follow the element assignment made by the Interface Message
Reference component.

The properties of the Interface Message Reference component are as follows:

  • {message label} REQUIRED. An xs:NCName. This property identifies the role
    this message plays in the {message exchange pattern} of the Interface
    Operation component this message is contained within. The value of this
    property MUST match the name of a placeholder message defined by the
    message exchange pattern.^†

  • {direction} REQUIRED. An xs:token with one of the values in or out,
    indicating whether the message is coming to the service or going from the
    service, respectively.^†  The direction MUST be the same as the direction
    of the message identified by the {message label} property in the {message
    exchange pattern} of the Interface Operation component this is contained
    within.^†

  • {message content model} REQUIRED. An xs:token with one of the values #any,
    #none, #other, or #element.^† A value of #any indicates that the message
    content is any single element. A value of #none indicates there is no
    message content. A value of #other indicates that the message content is
    described by some other extension property that references a declaration in
    a non-XML extension type system. A value of #element indicates that the
    message consists of a single element described by the global element
    declaration referenced by the {element declaration} property. This property
    is used only when the message is described using an XML-based data model.

  • {element declaration} OPTIONAL. A reference to an Element Declaration
    component in the {element declarations} property of the Description
    component. This element represents the content or “payload” of the message.
    When the {message content model} property has the value #any or #none, the
    {element declaration} property MUST be empty.^†

  • {parent} REQUIRED. The Interface Operation component that contains this
    component in its {interface message references} property.

For each Interface Message Reference component in the {interface message
references} property of an Interface Operation component, its {message label}
property MUST be unique.^†

If a type system not based upon the XML Infoset is in use (as considered in 3.2
Using Other Schema Languages), then additional properties would need to be
added to the Interface Message Reference component (along with extension
attributes to its XML representation) to allow associating such message types
with the message reference.

2.5.2 XML Representation of Interface Message Reference Component

<description>
  <interface>
    <operation>
      <input
            messageLabel="xs:NCName"?
            element="union of xs:QName, xs:token"? >
        <documentation />*
      </input>
      <output
            messageLabel="xs:NCName"?
            element="union of xs:QName, xs:token"? >
        <documentation />*
      </output>
    </operation>
  </interface>
</description>

The XML representation for an Interface Message Reference component is an
element information item with the following Infoset properties:

  • A [local name] of input or output

  • A [namespace name] of "http://www.w3.org/ns/wsdl"

  • Zero or more attribute information items amongst its [attributes] as
    follows:

      □ An OPTIONAL messageLabel attribute information item as described below
        in 2.5.2.1 messageLabel attribute information item with input or output
        [owner element].

      □ An OPTIONAL element attribute information item as described below in
        2.5.2.2 element attribute information item with input or output [owner
        element].

      □ Zero or more namespace qualified attribute information items whose
        [namespace name] is NOT "http://www.w3.org/ns/wsdl".

  • Zero or more element information item amongst its [children], in order, as
    follows:

     1. Zero or more documentation element information items (see 5.
        Documentation).

     2. Zero or more namespace-qualified element information items whose
        [namespace name] is NOT "http://www.w3.org/ns/wsdl".

2.5.2.1 messageLabel attribute information item with input or output [owner
element]

The messageLabel attribute information item identifies the role of this message
in the message exchange pattern of the given operation element information item
.

The messageLabel attribute information item has the following Infoset
properties:

  • A [local name] of messageLabel

  • A [namespace name] which has no value

The type of the messageLabel attribute information item is xs:NCName.

2.5.2.2 element attribute information item with input or output [owner element]

The element attribute information item has the following Infoset properties:

  • A [local name] of element.

  • A [namespace name] which has no value.

The type of the element attribute information item is a union of xs:QName and
xs:token where the allowed token values are #any, #none, or #other.

2.5.3 Mapping Interface Message Reference's XML Representation to Component
Properties

The mapping from the XML Representation of the interface message reference
element information item (see 2.5.2 XML Representation of Interface Message
Reference Component) to the properties of the Interface Message Reference
component (see 2.5.1 The Interface Message Reference Component) is as described
in Table 2-5 and uses the definitions below.

Define the message exchange pattern of the element information item to be the {
message exchange pattern} of the parent Interface Operation component.

Define the message direction of the element information item to be in if its
local name is input, and out if its local name is output.

Note that the messageLabel attribute information item of an interface message
reference element information item must be present if the message exchange
pattern has more than one placeholder message with {direction} equal to the
message direction.

If the messageLabel attribute information item of an interface message
reference element information item is present, then its actual value MUST match
the {message label} of some placeholder message with {direction} equal to the
message direction. ^†

If the messageLabel attribute information item of an interface message
reference element information item is absent then there MUST be a unique
placeholder message with {direction} equal to the message direction. ^†

Define the effective message label of an interface message reference element
information item to be either the actual value of the messageLabel attribute
information item if it is present, or the {message label} of the unique
placeholder message with {direction} equal to the message direction if the
attribute information item is absent.

If the local name is input then the message exchange pattern MUST have at least
one placeholder message with direction "In".^†

If the local name is output then the message exchange pattern MUST have at
least one placeholder message with direction "Out".^†

If the local name is infault then the message exchange pattern MUST support at
least one fault in the "In" direction.^†

If the local name is outfault then the message exchange pattern MUST support at
least one fault in the "Out" direction.^†

   Table 2-5. Mapping from XML Representation to Interface Message Reference
                             Component Properties
┌────────────┬────────────────────────────────────────────────────────────────┐
│  Property  │                             Value                              │
├────────────┼────────────────────────────────────────────────────────────────┤
│{message    │The effective message label.                                    │
│label}      │                                                                │
├────────────┼────────────────────────────────────────────────────────────────┤
│{direction} │The message direction.                                          │
├────────────┼────────────────────────────────────────────────────────────────┤
│{message    │If the element attribute information item is present and its    │
│content     │value is a QName, then #element; otherwise the actual value of  │
│model}      │the element attribute information item, if any; otherwise #other│
│            │.                                                               │
├────────────┼────────────────────────────────────────────────────────────────┤
│            │If the element attribute information item is present and its    │
│            │value is a QName, then the Element Declaration component from   │
│            │the {element declarations} property of the Description component│
│{element    │resolved to by the value of the element attribute information   │
│declaration}│item (see 2.17 QName resolution); otherwise empty. If the       │
│            │element attribute information item has a value, then it MUST    │
│            │resolve to an Element Declaration component from the {element   │
│            │declarations} property of the Description component.^†          │
├────────────┼────────────────────────────────────────────────────────────────┤
│{parent}    │The Interface Operation component corresponding to the interface│
│            │element information item in [parent].                           │
└────────────┴────────────────────────────────────────────────────────────────┘


2.6 Interface Fault Reference

2.6.1 The Interface Fault Reference Component

An Interface Fault Reference component associates a defined type, specified by
an Interface Fault component, to a fault message exchanged in an operation.

A message exchange pattern defines a set of placeholder messages that
participate in the pattern and assigns them unique message labels within the
pattern (e.g. 'In', 'Out'). The purpose of an Interface Fault Reference
component is to associate an actual message type (XML element declaration or
some other declaration (see 3.2 Using Other Schema Languages) for message
content, as specified by an Interface Fault component) with a fault message
occurring in the pattern. In order to identify the fault message it describes,
the Interface Fault Reference component uses the message label of the message
the fault is associated with, as a key.

As indicated earlier, the companion specification [WSDL 2.0 Adjuncts] defines
several fault propagation rulesets that a given message exchange pattern may
use. For the ruleset fault-replaces-message, the message that the fault relates
to identifies the message in place of which the declared fault message will
occur. Thus, the fault message will travel in the same direction as the message
it replaces in the pattern. For the ruleset message-triggers-fault, the message
that the fault relates to identifies the message after which the indicated
fault may occur, in the opposite direction of the referred to message. That is,
the fault message will travel in the opposite direction of the message it comes
after in the message exchange pattern.

The properties of the Interface Fault Reference component are as follows:

  • {interface fault} REQUIRED. An Interface Fault component in the {interface
    faults} property of the [parent] Interface Operation component's [parent]
    Interface component, or an Interface component that it directly or
    indirectly extends. Identifying the Interface Fault component therefore
    indirectly defines the actual content or payload of the fault message.

  • {message label} REQUIRED. An xs:NCName. This property identifies the
    message this fault relates to among those defined in the {message exchange
    pattern} property of the Interface Operation component it is contained
    within. The value of this property MUST match the name of a placeholder
    message defined by the message exchange pattern.^†

  • {direction} REQUIRED. A xs:token with one of the values in or out,
    indicating whether the fault is coming to the service or going from the
    service, respectively. The direction MUST be consistent with the direction
    implied by the fault propagation ruleset used in the message exchange
    pattern of the operation.^† For example, if the ruleset
    fault-replaces-message is used, then a fault that refers to an outgoing
    message would have a {direction} property value of out. On the other hand,
    if the ruleset message-triggers-fault is used, then a fault that refers to
    an outgoing message would have a {direction} property value of in as the
    fault travels in the opposite direction of the message.

  • {parent} REQUIRED. The Interface Operation component that contains this
    component in its {interface fault references} property.

For each Interface Fault Reference component in the {interface fault references
} property of an Interface Operation component, the combination of its {
interface fault} and {message label} properties MUST be unique.^†

2.6.2 XML Representation of Interface Fault Reference

<description>
  <interface>
    <operation>
      <infault
            ref="xs:QName"
            messageLabel="xs:NCName"? >
        <documentation />*
      </infault>*
      <outfault
            ref="xs:QName"
            messageLabel="xs:NCName"? >
        <documentation />*
      </outfault>*
    </operation>
  </interface>
</description>

The XML representation for an Interface Fault Reference component is an element
information item with the following Infoset properties:

  • A [local name] of infault or outfault

  • A [namespace name] of "http://www.w3.org/ns/wsdl"

  • One or more attribute information items amongst its [attributes] as
    follows:

      □ A REQUIRED ref attribute information item as described below in 2.6.2.1
        ref attribute information item with infault, or outfault [owner
        element].

      □ An OPTIONAL messageLabel attribute information item as described below
        in 2.6.2.2 messageLabel attribute information item with infault, or
        outfault [owner element].

      □ Zero or more namespace qualified attribute information items whose
        [namespace name] is NOT "http://www.w3.org/ns/wsdl".

  • Zero or more element information item amongst its [children], in order, as
    follows:

     1. Zero or more documentation element information items (see 5.
        Documentation).

     2. Zero or more namespace-qualified element information items whose
        [namespace name] is NOT "http://www.w3.org/ns/wsdl".

2.6.2.1 ref attribute information item with infault, or outfault [owner
element]

The ref attribute information item refers to a fault component.

The ref attribute information item has the following Infoset properties:

  • A [local name] of ref

  • A [namespace name] which has no value

The type of the ref attribute information item is xs:QName.

2.6.2.2 messageLabel attribute information item with infault, or outfault
[owner element]

The messageLabel attribute information item identifies the message in the
message exchange pattern of the given operation element information item that
is associated with this fault.

The messageLabel attribute information item has the following Infoset
properties:

  • A [local name] of messageLabel

  • A [namespace name] which has no value

The type of the messageLabel attribute information item is xs:NCName.

The messageLabel attribute information item MUST be present in the XML
representation of an Interface Fault Reference component with a given {
direction}, if the {message exchange pattern} of the parent Interface Operation
component has more than one fault with that direction.^† Recall that the fault
propagation ruleset of the {message exchange pattern} specifies the relation
between faults and messages. For example, the fault-replaces-message ruleset
specifies that the faults have the same direction as the messages, while the
message-triggers-fault ruleset specifies that the faults have the opposite
direction from the messages.

2.6.3 Mapping Interface Fault Reference's XML Representation to Component
Properties

The mapping from the XML Representation of the message reference element
information item (see 2.6.2 XML Representation of Interface Fault Reference) to
the properties of the Interface Fault Reference component (see 2.6.1 The
Interface Fault Reference Component) is as described in Table 2-6 and uses the
definitions below.

Define the message exchange pattern of the element information item to be the {
message exchange pattern} of the parent Interface Operation component.

Define the fault direction of the element information item to be in if its
local name is infault and out if its local name is outfault.

Define the message direction of the element information item to be the {
direction} of the placeholder message associated with the fault as specified by
the fault propagation ruleset of the message exchange pattern.

The messageLabel attribute information item of an interface fault reference
element information item MUST be present if the message exchange pattern has
more than one placeholder message with {direction} equal to the message
direction. ^†

If the messageLabel attribute information item of an interface fault reference
element information item is present then its actual value MUST match the {
message label} of some placeholder message with {direction} equal to the
message direction. ^†

If the messageLabel attribute information item of an interface fault reference
element information item is absent then there MUST be a unique placeholder
message with {direction} equal to the message direction. ^†

Define the effective message label of an interface fault reference element
information item to be either the actual value of the messageLabel attribute
information item if it is present, or the {message label} of the unique
placeholder message whose {direction} is equal to the message direction if the
attribute information item is absent.

    Table 2-6. Mapping from XML Representation to Interface Fault Reference
                             Component Properties
┌───────────┬─────────────────────────────────────────────────────────────────┐
│ Property  │                              Value                              │
├───────────┼─────────────────────────────────────────────────────────────────┤
│           │The Interface Fault component from {interface faults} property of│
│{interface │the parent Interface component, or an Interface component that it│
│fault}     │directly or indirectly extends, with {name} equal to the actual  │
│           │value of the ref attribute information item.                     │
├───────────┼─────────────────────────────────────────────────────────────────┤
│{message   │The effective message label.                                     │
│label}     │                                                                 │
├───────────┼─────────────────────────────────────────────────────────────────┤
│{direction}│The fault direction.                                             │
├───────────┼─────────────────────────────────────────────────────────────────┤
│{parent}   │The Interface Operation component corresponding to the interface │
│           │element information item in [parent].                            │
└───────────┴─────────────────────────────────────────────────────────────────┘


2.7 Binding

2.7.1 The Binding Component

A Binding component describes a concrete message format and transmission
protocol which may be used to define an endpoint (see 2.13 Endpoint). That is,
a Binding component defines the implementation details necessary to access the
service.

Binding components can be used to describe such information in a reusable
manner for any interface or specifically for a given interface. Furthermore,
binding information MAY be specified on a per-operation basis (see 2.9.1 The
Binding Operation Component) within an interface, in addition to across all
operations of an interface.

If a Binding component specifies any operation-specific binding details (by
including Binding Operation components) or any fault binding details (by
including Binding Fault components), then it MUST specify an interface the
Binding component applies to, so as to indicate which interface the operations
come from.^†

Conversely, a Binding component which omits any operation-specific binding
details and any fault binding details MAY omit specifying an interface. Binding
components that do not specify an interface MAY be used to specify
operation-independent binding details for Service components with different
interfaces. That is, such Binding components are reusable across one or more
interfaces.

No concrete binding details are given in this specification. The companion
specification, Web Services Description Language (WSDL) Version 2.0 Part 2:
Adjuncts [WSDL 2.0 Adjuncts] defines such bindings for SOAP 1.2 [SOAP 1.2 Part
1: Messaging Framework (Second Edition)] and HTTP [IETF RFC 2616]. Other
specifications MAY define additional binding details. Such specifications are
expected to annotate the Binding component (and its sub-components) with
additional properties and specify the mapping from the XML representation to
these properties.

A Binding component that defines bindings for an Interface component MUST
define bindings for all the operations and faults of that Interface component.^
† The bindings can occur via defaulting rules which allow one to specify
default bindings for all operations and faults (see, for example [WSDL 2.0
Adjuncts]) or by defining bindings for each Interface Operation and Interface
Fault component of the Interface component.

Similarly, whenever a reusable Binding component (i.e. one that does not
specify an Interface component) is applied to a specific Interface component in
the context of an Endpoint component (see 2.13.1 The Endpoint Component), the
Binding component MUST define bindings for each Interface Operation and
Interface Fault component of the Interface component, via a combination of
properties defined on the Binding component itself and default binding rules
specific to its binding type.^†

A Binding component that defines bindings for an Interface component MUST
define bindings for all the faults of that Interface component that are
referenced from any of the operations in that Interface component.^† As for the
case of operations, the binding can be defined by defaulting rules. Note that
only the faults actually referenced by operations are required to have
bindings.

Bindings are named constructs and can be referred to by QName (see 2.17 QName
resolution). For instance, Endpoint components refer to bindings in this way.

The properties of the Binding component are as follows:

  • {name} REQUIRED. An xs:QName.

  • {interface} OPTIONAL. An Interface component indicating the interface for
    which binding information is being specified.

  • {type} REQUIRED. An xs:anyURI. This xs:anyURI MUST be an absolute IRI as
    defined by [IETF RFC 3987].^† The value of this IRI indicates what kind of
    concrete binding details are contained within this Binding component.
    Specifications (such as [WSDL 2.0 Adjuncts]) that define such concrete
    binding details MUST specify appropriate values for this property. The
    value of this property MAY be the namespace name of the extension elements
    or attributes which define those concrete binding details.

  • {binding faults} OPTIONAL. A set of Binding Fault components.

  • {binding operations} OPTIONAL. A set of Binding Operation components.

For each Binding component in the {bindings} property of a Description
component, the {name} property MUST be unique.^†

2.7.2 XML Representation of Binding Component

<description>
  <binding
        name="xs:NCName"
        interface="xs:QName"?
        type="xs:anyURI" >
    <documentation />*
    [ <fault /> | <operation /> ]*
  </binding>
</description>

The XML representation for a Binding component is an element information item
with the following Infoset properties:

  • A [local name] of binding

  • A [namespace name] of "http://www.w3.org/ns/wsdl"

  • Two or more attribute information items amongst its [attributes] as
    follows:

      □ A REQUIRED name attribute information item as described below in
        2.7.2.1 name attribute information item with binding [owner element].

      □ An OPTIONAL interface attribute information item as described below in
        2.7.2.2 interface attribute information item with binding [owner
        element].

      □ An REQUIRED type attribute information item as described below in
        2.7.2.3 type attribute information item with binding [owner element].

      □ Zero or more namespace qualified attribute information items whose
        [namespace name] is NOT "http://www.w3.org/ns/wsdl".

  • Zero or more element information items amongst its [children], in order, as
    follows:

     1. Zero or more documentation element information items (see 5.
        Documentation).

     2. Zero or more element information items from among the following, in any
        order:

          ☆ Zero or more fault element information items (see 2.8.2 XML
            Representation of Binding Fault Component).

          ☆ Zero or more operation element information items (see 2.9.2 XML
            Representation of Binding Operation Component).

          ☆ Zero or more namespace-qualified element information items whose
            [namespace name] is NOT "http://www.w3.org/ns/wsdl". Such element
            information items are considered to be binding extension elements
            (see 2.7.2.4 Binding extension elements).

2.7.2.1 name attribute information item with binding [owner element]

The name attribute information item together with the targetNamespace attribute
information item of the description element information item forms the QName of
the binding.

The name attribute information item has the following Infoset properties:

  • A [local name] of name

  • A [namespace name] which has no value

The type of the name attribute information item is xs:NCName.

2.7.2.2 interface attribute information item with binding [owner element]

The interface attribute information item refers, by QName, to an Interface
component.

The interface attribute information item has the following Infoset properties:

  • A [local name] of interface

  • A [namespace name] which has no value

The type of the interface attribute information item is xs:QName.

2.7.2.3 type attribute information item with binding [owner element]

The type attribute information item identifies the kind of binding details
contained in the Binding component.

The type attribute information item has the following Infoset properties:

  • A [local name] of type

  • A [namespace name] which has no value

The type of the type attribute information item is xs:anyURI.

2.7.2.4 Binding extension elements

Binding extension elements are used to provide information specific to a
particular binding. The semantics of such element information items are defined
by the specification for those element information items. Such specifications
are expected to annotate the Binding component with additional properties and
specify the mapping from the XML representation to those properties.

2.7.3 Mapping Binding's XML Representation to Component Properties

The mapping from the XML Representation of the binding element information item
(see 2.7.2 XML Representation of Binding Component) to the properties of the
Binding component (see 2.7.1 The Binding Component) is as described in Table
2-7.

  Table 2-7. Mapping from XML Representation to Binding Component Properties
┌───────────┬─────────────────────────────────────────────────────────────────┐
│ Property  │                              Value                              │
├───────────┼─────────────────────────────────────────────────────────────────┤
│           │The QName whose local name is the actual value of the name       │
│{name}     │attribute information item and whose namespace name is the actual│
│           │value of the targetNamespace attribute information item of the   │
│           │[parent] description element information item.                   │
├───────────┼─────────────────────────────────────────────────────────────────┤
│           │The Interface component resolved to by the actual value of the   │
│{interface}│interface attribute information item (see 2.17 QName resolution),│
│           │if any.                                                          │
├───────────┼─────────────────────────────────────────────────────────────────┤
│{type}     │The actual value of the type attribute information item.         │
├───────────┼─────────────────────────────────────────────────────────────────┤
│{binding   │The set of Binding Fault components corresponding to the fault   │
│faults}    │element information items in [children], if any.                 │
├───────────┼─────────────────────────────────────────────────────────────────┤
│{binding   │The set of Binding Operation components corresponding to the     │
│operations}│operation element information items in [children], if any.       │
└───────────┴─────────────────────────────────────────────────────────────────┘


2.8 Binding Fault

2.8.1 The Binding Fault Component

A Binding Fault component describes a concrete binding of a particular fault
within an interface to a particular concrete message format. A particular fault
of an interface is uniquely identified by its {name} property.

Note that the fault does not occur by itself -it occurs as part of a message
exchange as defined by an Interface Operation component (and its binding
counterpart the Binding Operation component). Thus, the fault binding
information specified in a Binding Fault component describes how faults that
occur within a message exchange of an operation will be formatted and carried
in the transport.

The properties of the Binding Fault component are as follows:

  • {interface fault} REQUIRED. An Interface Fault component in the {interface
    faults} property of the Interface component identified by the {interface}
    property of the parent Binding component, or an Interface component that
    that Interface component directly or indirectly extends. This is the
    Interface Fault component for which binding information is being specified.

  • {parent} REQUIRED. The Binding component that contains this component in
    its {binding faults} property.

For each Binding Fault component in the {binding faults} property of a Binding
component, the {interface fault} property MUST be unique.^† That is, one cannot
define multiple bindings for the same fault within a given Binding component.

2.8.2 XML Representation of Binding Fault Component

<description>
  <binding>
    <fault
          ref="xs:QName" >
      <documentation />*
    </fault>
  </binding>
</description>

The XML representation for a Binding Fault component is an element information
item with the following Infoset properties:

  • A [local name] of fault

  • A [namespace name] of "http://www.w3.org/ns/wsdl"

  • One or more attribute information items amongst its [attributes] as
    follows:

      □ A REQUIRED ref attribute information item as described below in 2.8.2.1
        ref attribute information item with fault [owner element].

      □ Zero or more namespace qualified attribute information items whose
        [namespace name] is NOT "http://www.w3.org/ns/wsdl".

  • Zero or more element information item amongst its [children], in order, as
    follows:

     1. Zero or more documentation element information items (see 5.
        Documentation).

     2. Zero or more namespace-qualified element information items whose
        [namespace name] is NOT "http://www.w3.org/ns/wsdl". Such element
        information items are considered to be binding fault extension elements
        as described further below (see 2.8.2.2 Binding Fault extension
        elements).

2.8.2.1 ref attribute information item with fault [owner element]

The ref attribute information item has the following Infoset properties:

  • A [local name] of ref

  • A [namespace name] which has no value

The type of the ref attribute information item is xs:QName.

2.8.2.2 Binding Fault extension elements

Binding Fault extension elements are used to provide information specific to a
particular fault in a binding. The semantics of such element information items
are defined by the specification for those element information items. Such
specifications are expected to annotate the Binding Fault component with
additional properties and specify the mapping from the XML representation to
those properties.

2.8.3 Mapping Binding Fault's XML Representation to Component Properties

The mapping from the XML Representation of the fault element information item
(see 2.8.2 XML Representation of Binding Fault Component) to the properties of
the Binding Fault component (see 2.8.1 The Binding Fault Component) is as
described in Table 2-8.

     Table 2-8. Mapping from XML Representation to Binding Fault Component
                                  Properties
┌───────────┬─────────────────────────────────────────────────────────────────┐
│ Property  │                              Value                              │
├───────────┼─────────────────────────────────────────────────────────────────┤
│{interface │The Interface Fault component corresponding to the actual value  │
│fault}     │of the ref attribute information item.                           │
├───────────┼─────────────────────────────────────────────────────────────────┤
│{parent}   │The Binding component corresponding to the binding element       │
│           │information item in [parent].                                    │
└───────────┴─────────────────────────────────────────────────────────────────┘


2.9 Binding Operation

2.9.1 The Binding Operation Component

The Binding Operation component describes the concrete message format(s) and
protocol interaction(s) associated with a particular interface operation for a
given endpoint. A particular operation of an interface is uniquely identified
by its {name} property.

The properties of the Binding Operation component are as follows:

  • {interface operation} REQUIRED. An Interface Operation component in the {
    interface operations} property of the Interface component identified by the
    {interface} property of the [parent] Binding component, or an Interface
    component that that Interface component directly or indirectly extends.
    This is the Interface Operation component for which binding information is
    being specified.

  • {binding message references} OPTIONAL. A set of Binding Message Reference
    components.

  • {binding fault references} OPTIONAL. A set of Binding Fault Reference
    components.

  • {parent} REQUIRED. The Binding component that contains this component in
    its {binding operations} property.

For each Binding Operation component in the {binding operations} property of a
Binding component, the {interface operation} property MUST be unique.^† That
is, one cannot define multiple bindings for the same operation within a given
Binding component.

2.9.2 XML Representation of Binding Operation Component

<description>
  <binding>
    <operation
          ref="xs:QName" >
      <documentation />*
      [ <input /> | <output /> | <infault /> | <outfault /> ]*
    </operation>
  </binding>
</description>

The XML representation for a Binding Operation component is an element
information item with the following Infoset properties:

  • A [local name] of operation

  • A [namespace name] of "http://www.w3.org/ns/wsdl"

  • One or more attribute information items amongst its [attributes] as
    follows:

      □ A REQUIRED ref attribute information item as described below in 2.9.2.1
        ref attribute information item with operation [owner element].

      □ Zero or more namespace qualified attribute information items whose
        [namespace name] is NOT "http://www.w3.org/ns/wsdl".

  • Zero or more element information items amongst its [children], in order, as
    follows:

     1. Zero or more documentation element information items (see 5.
        Documentation).

     2. Zero or more element information items from among the following, in any
        order:

          ☆ Zero or more input element information items (see 2.10 Binding
            Message Reference)

          ☆ Zero or more output element information items (see 2.10 Binding
            Message Reference)

          ☆ Zero or more infault element information items (see 2.11 Binding
            Fault Reference)

          ☆ Zero or more outfault element information items (see 2.11 Binding
            Fault Reference)

          ☆ Zero or more namespace-qualified element information item whose
            [namespace name] is NOT " http://www.w3.org/ns/wsdl ". Such element
            information items are considered to be binding operation extension
            elements as described below (see 2.9.2.2 Binding Operation
            extension elements).

2.9.2.1 ref attribute information item with operation [owner element]

The ref attribute information item has the following Infoset properties:

  • A [local name] of ref

  • A [namespace name] which has no value

The type of the ref attribute information item is xs:QName.

2.9.2.2 Binding Operation extension elements

Binding Operation extension elements are used to provide information specific
to a particular operation in a binding. The semantics of such element
information items are defined by the specification for those element
information items. Such specifications are expected to annotate the Binding
Operation component with additional properties and specify the mapping from the
XML representation to those properties.

2.9.3 Mapping Binding Operation's XML Representation to Component Properties

The mapping from the XML Representation of the operation element information
item (see 2.9.2 XML Representation of Binding Operation Component) to the
properties of the Binding Operation component is as described in Table 2-9.

   Table 2-9. Mapping from XML Representation to Binding Operation Component
                                  Properties
┌──────────────┬──────────────────────────────────────────────────────────────┐
│   Property   │                            Value                             │
├──────────────┼──────────────────────────────────────────────────────────────┤
│{interface    │The Interface Operation component corresponding to the actual │
│operation}    │value of the ref attribute information item.                  │
├──────────────┼──────────────────────────────────────────────────────────────┤
│{binding      │The set of Binding Message Reference components corresponding │
│message       │to the input and output element information items in          │
│references}   │[children], if any.                                           │
├──────────────┼──────────────────────────────────────────────────────────────┤
│{binding fault│The set of Binding Fault Reference components corresponding to│
│references}   │the infault and outfault element information items in         │
│              │[children], if any.                                           │
├──────────────┼──────────────────────────────────────────────────────────────┤
│{parent}      │The Binding component corresponding to the binding element    │
│              │information item in [parent].                                 │
└──────────────┴──────────────────────────────────────────────────────────────┘


2.10 Binding Message Reference

2.10.1 The Binding Message Reference Component

A Binding Message Reference component describes a concrete binding of a
particular message participating in an operation to a particular concrete
message format.

The properties of the Binding Message Reference component are as follows:

  • {interface message reference} REQUIRED. An Interface Message Reference
    component among those in the {interface message references} property of the
    Interface Operation component being bound by the containing Binding
    Operation component.

  • {parent} REQUIRED. The Binding Operation component that contains this
    component in its {binding message references} property.

For each Binding Message Reference component in the {binding message references
} property of a Binding Operation component, the {interface message reference}
property MUST be unique.^† That is, the same message cannot be bound twice
within the same operation.

2.10.2 XML Representation of Binding Message Reference Component

<description>
  <binding>
    <operation>
      <input
            messageLabel="xs:NCName"? >
        <documentation />*
      </input>
      <output
            messageLabel="xs:NCName"? >
        <documentation />*
      </output>
    </operation>
  </binding>
</description>

The XML representation for a Binding Message Reference component is an element
information item with the following Infoset properties:

  • A [local name] of input or output.

  • A [namespace name] of "http://www.w3.org/ns/wsdl".

  • Zero or more attribute information items amongst its [attributes] as
    follows:

      □ An OPTIONAL messageLabel attribute information item as described below
        in 2.10.2.1 messageLabel attribute information item with input or
        output [owner element].

      □ Zero or more namespace qualified attribute information items whose
        [namespace name] is NOT "http://www.w3.org/ns/wsdl".

  • Zero or more element information item amongst its [children], in order, as
    follows:

     1. Zero or more documentation element information items (see 5.
        Documentation).

     2. Zero or more namespace-qualified element information items whose
        [namespace name] is NOT "http://www.w3.org/ns/wsdl". Such element
        information items are considered to be binding message reference
        extension elements as described below (see 2.10.2.2 Binding Message
        Reference extension elements).

2.10.2.1 messageLabel attribute information item with input or output [owner
element]

The messageLabel attribute information item has the following Infoset
properties:

  • A [local name] of messageLabel.

  • A [namespace name] which has no value.

The type of the messageLabel attribute information item is xs:NCName.

2.10.2.2 Binding Message Reference extension elements

Binding Message Reference extension elements are used to provide information
specific to a particular message in an operation. The semantics of such element
information items are defined by the specification for those element
information items. Such specifications are expected to annotate t