W3C

Web Services Description Language (WSDL) Version 2.0: RDF Mapping

W3C Working Draft 23 May 2007

This version:
http://www.w3.org/TR/2007/WD-wsdl20-rdf-20070523/
Latest version:
http://www.w3.org/TR/wsdl20-rdf
Previous version:
http://www.w3.org/TR/2007/WD-wsdl20-rdf-20070326/
Editors:
Jacek Kopecký, DERI Innsbruck
Bijan Parsia, University of Maryland

Abstract

Web Services Description Language (WSDL) provides a model and an XML format for describing Web services. This document describes a representation of that model in the Resource Description Language (RDF) and in the Web Ontology Language (OWL), and a mapping procedure for transforming particular WSDL descriptions into their RDF form.

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 the W3C Working Draft of Web Services Description Language (WSDL) Version 2.0: RDF Mapping, produced by the Web Services Description Working Group, as part of the W3C Web Services Activity.

Once all the comments and issues about this document will have been addressed, the Working Group intends to publish a final version of this document as a W3C Working Group Note.

This version contains the complete RDF mapping for WSDL 2.0. A diff-marked version against the previous version of this document is available.

Comments on this specification are to be sent to the public public-ws-desc-comments@w3.org mailing list (public archive).

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 Naming and Notation Conventions
    1.2 Organization of this specification
    1.3 Conformance
2. WSDL Ontology
    2.1 Core WSDL Components
        2.1.1 Description component
        2.1.2 Interface classes
        2.1.3 Binding classes
        2.1.4 Service classes
    2.2 Handling Extensions and Documentation
    2.3 Message Exchange Patterns
    2.4 Predefined Extensions
    2.5 Operation Styles
    2.6 SOAP Binding
    2.7 HTTP Binding
3. Example WSDL document in RDF form
4. Differences from the WSDL Component Model (Non-Normative)
    4.1 Component naming
    4.2 Documents, imports and includes
    4.3 Component references
    4.4 Representing properties with classes
    4.5 Other WSDL restrictions not enforced by the ontology
5. References

Appendices

A. The OWL Ontology Source
B. List of URIs used by the WSDL RDF mapping (Non-Normative)
C. Acknowledgments (Non-Normative)


1. Introduction

Web Services Description Language is defined in XML, because XML is a common format for exchange of structured information. WSDL generators and parsers benefit from the wide availability of XML processing libraries, and the use of XML Schema makes the structure of WSDL well constrained, yet extensible. On the other hand, XML in general does not provide generic rules for composing different vocabularies, so combining for example the WSDL description of a Web service, the service's policies and other information (presumably expressed in XML) can be done in many significantly different ways (e.g. extending WSDL, extending the policy language, creating a special XML container for all the information etc.), and little interoperability can be expected when such combined documents are used.

For example, a policy can be combined with WSDL by adding the policy elements in WSDL service element. Equally, a WSDL description can be combined with a policy by adding the WSDL description as part of the policy. While the results should be similar (WSDL with policy information), they are in fact very different for the processing software, and a policy in WSDL cannot easily be used by software that does not understand WSDL.

The Semantic web allows knowledge from many different sources to be easily combined so that unexpected data connections can be used. Thanks to the Resource Description Framework (RDF) graph structure, together with the use of URIs for identifying nodes, it is very easy for different documents to be brought together. If some WSDL document describes a Web service, a policy document expresses constraints and capabilities of the service and a general description specifies the author of the service, all this information can be merged in RDF and the resulting graph will contain all three kinds of information associated with the single service.

The main objective of this specification is to present a standard RDF ([RDF]) and OWL ([OWL]) vocabulary to express WSDL 2.0, so that WSDL 2.0 documents can be transformed into RDF and merged with other Semantic Web data. This specification can be implemented as a standalone tool, as part of a tool that generates WSDL descriptions (outputting the RDF form in parallel to the XML form), or as part of a tool that processes RDF data, enabling the ability to read WSDL documents as RDF input.

Note: the readers of this document are expected to have an understanding of the WSDL language and the WSDL component model (see [WSDL 2.0 Core Language]); this document is not a standalone specification of the WSDL ontology, independent of WSDL specification. Further, the readers are expected to have good knowledge of RDF and at least basic knowledge of OWL.

1.1 Naming and Notation Conventions

The ontology presented in this specification describes concepts introduced in WSDL 2.0 (see [WSDL 2.0 Core Language] and [WSDL 2.0 Adjuncts]), from where we adopt the names for the ontology classes, properties and distinguished instances.

In WSDL 2.0, components and their properties are named with words separated with spaces, for example Interface Operation component with {message exchange pattern} property. In this document, we write all WSDL 2.0 components and properties in italic. In the WSDL ontology, we use the so-called camelCase, with upper-case first letter for class names (InterfaceOperation) and lower-case first letter for properties (messageExchangePattern). We write all the WSDL ontology identifiers in monospace.

The above naming transformation (remove spaces, use camelCase) is used for the majority of components and their properties modeled in our ontology, with several exception indicated in the text in this specification. One recurring exception is that the multivalued properties (like Interface.{interface operations}) are not modeled as a single plural property (say interfaceOperations) but instead as a singular property to be used multiple times (i.e. interfaceOperation in our case), as the order of the values is irrelevant in WSDL.

In the mapping tables below, we use a simple triple syntax, each triple on one line. Variables to be filled in (like generated IDs and property values) are in angle brackets, for example <id> generally means the ID of the current component. Literal values are in double quotes, optionally indicating the data type after double caret, for example "<code>"^^xs:int for HTTP status codes. The default data type is xs:string. Finally, comments are in parentheses and italic (like this).

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-rdf#
wsdlx
http://www.w3.org/ns/wsdl-extensions#
wsoap
http://www.w3.org/ns/wsdl/soap#
whttp
http://www.w3.org/ns/wsdl/http#
wrpc
http://www.w3.org/ns/wsdl/rpc#
rdf
http://www.w3.org/1999/02/22-rdf-syntax-ns#
rdfs
http://www.w3.org/2000/01/rdf-schema#
xs
http://www.w3.org/2001/XMLSchema#
sawsdl
http://www.w3.org/ns/sawsdl#
ex
http://example.com/#

1.2 Organization of this specification

The remainder of this specification is split into three major sections and two appendices:

1.3 Conformance

This document defines a mapping from valid WSDL 2.0 documents (interpreted as the corresponding component model), into sets of RDF statements. A conforming mapping processor must follow all the mappings specified in the mapping tables in Section 2 of this document, to the extent of its understanding of the optional WSDL extensions. A WSDL processor that does not support the SOAP binding, for example, may not implement any mappings specified in Section 2.6.

This specification does not mandate a particular form of generated unique identifiers; while the example in Section 3 uses the urn:uuid: scheme, this is not required by this specification. Therefore, the RDF mapping of a single WSDL document may differ in these generated identifiers when created by different tools, or even when created by the same tool at different times.

While this RDF mapping does not (and cannot) handle WSDL extensions in general (apart from those predefined by the WSDL 2.0 specifications), implementations of the RDF mapping may support other WSDL extensions and enhance the resulting RDF graph with the appropriate statements. An RDF mapping implementation conforms to this specification if it produces all the statements mandated by the mapping tables herein; it may produce additional statements as well.

2. WSDL Ontology

This section describes the OWL ontology for WSDL, comparing it to the WSDL component model defined in [WSDL 2.0 Core Language] and [WSDL 2.0 Adjuncts]. The text in this section aims to be a comprehensive explanation of the mapping, and the formal normative mappings are specified in the mapping tables at the end of each subsection. Note that the URIs defined by the WSDL 2.0 specification (binding types, operation styles, message exchange patterns etc.) are not repeated in the mapping tables.

This section also touches briefly on some differences between the OWL ontology and the component model, but for the full account of these differences and for the rationales see section 4.

The RDF mapping for the core WSDL components defined in [WSDL 2.0 Core Language] is described in section 2.1. WSDL components are extensible, so section 2.2 describes how extensions are mapped to RDF. The following sections, from 2.3 to 2.7, describe the mapping for the various adjuncts specified in [WSDL 2.0 Adjuncts].

2.1 Core WSDL Components

The main components of WSDL are represented as classes in the WSDL ontology: Description, Interface, Binding and Service, as described in the following subsections. This means that every interface, binding and service described by WSDL will be mapped to a single instance in the RDF representation.

2.1.1 Description class

The top-level WSDL component — Description — is mapped to a single instance of the class Description, which uses the properties interface, binding and service to point to its constituents, i.e. all the interfaces, bindings and services.

Note that since we do not model element declarations and type definitions further than just the QNames, we do not reference them from the Description instance. This also means that while all WSDL component models implicitly contain all XML Schema simple type definitions, the RDF mapping does not show them. It is possible that if an RDF mapping is created for XML Schema, instead of referencing the QNames, a future version of this WSDL RDF mapping can use direct pointers to the XML Schema component designators for the element declarations and type definitions.

A mapping of a single WSDL document (together with any imports or includes) will always result in a single instance of the Description class. However, there can be multiple individuals of the class Description in a knowledge base that contains the information from multiple WSDL documents. The core WSDL specification does not consider the case of combining multiple independent WSDL documents and it does not mandate that independent documents consistently describe components with the same name. This is, however, an assumption when combining the RDF representation of multiple WSDL documents. The normative WSDL RDF mapping does not consider merging multiple differing definitions of a component with the same name, but some possible resulting problems are pointed out in section 4.2.

Table 2-1. Mapping Description Components to RDF
Property RDF Form
  (id generated per IRI-References for WSDL 2.0 Components)
<id> rdf:type wsdl:Description .
{interfaces} (for interface mapping see Table 2-3)
{bindings} (for binding mapping see Table 2-8)
{services} (for service mapping see Table 2-13)
{type definitions} (not mapped)
{element declarations} (not mapped)

Table 2-2. Mapping QNames to RDF
RDF Form
(qnameId is a newly generated unique URI)
<qnameId> rdf:type wsdl:QName .
<qnameId> wsdl:localName "<localName>" .
<qnameId> wsdl:namespace <namespace> .

2.1.2 Interface classes

All WSDL Interface components are represented in RDF as instances of the Interface class. WSDL interfaces can extend other WSDL interfaces, which is indicated by the property extends. Interfaces may have operations and faults, represented as instances of the InterfaceOperation and InterfaceFault classes, and each pointed to with the properties interfaceOperation and interfaceFault, respectively.

Interfaces, operations and faults each have a name, which is a QName. The namespace IRI part of this QName is present before the fragment ID of the component identifier, and the local name is represented in the RDF form as a literal value of the property rdfs:label.

There are a number of properties applicable to InterfaceOperation instances (corresponding to the properties of the WSDL Interface Operation component):

Instances of InterfaceMessageReference and InterfaceFaultReference can indicate their direction — input message references and input fault references all belong to the class InputMessage and output message references and output fault references all belong to the class OutputMessage. Further, both message references and fault references indicate the appropriate message labels (instances of MessageLabel, representing particular messages in the operation's MEP) using the property messageLabel. (In section 2.3 we describe how message exchange patterns are modeled in our RDF mapping.)

Furthermore, instances of InterfaceMessageReference and of InterfaceFault point to element declarations (as QName instances) using the property elementDeclaration and specify their message content model with the property messageContentModel, indicating one of the four possible instances of the class MessageContentModel. And finally, instances of InterfaceFaultReference refer to their interface faults directly using the property interfaceFault.

Table 2-3. Mapping Interface Components to RDF
Property RDF Form
  (id generated per IRI-References for WSDL 2.0 Components)
<id> rdf:type wsdl:Interface .
<parentDescriptionId> wsdl:interface <id> .
{name} <id> rdfs:label "<localPart>" .
{extended interfaces} (for each Interface component)
<id> wsdl:extends <anotherInterfaceId> .
{interface operations} (for interface operation mapping see Table 2-4)
{interface faults} (for interface fault mapping see Table 2-5)

Table 2-4. Mapping Interface Operation Components to RDF
Property RDF Form
  (id generated per IRI-References for WSDL 2.0 Components)
<id> rdf:type wsdl:InterfaceOperation .
<parentInterfaceId> wsdl:interfaceOperation <id> .
{name} <id> rdfs:label "<localPart>" .
{interface message references} (for interface message reference mapping see Table 2-6)
{interface fault references} (for interface fault reference mapping see Table 2-7)
{message exchange pattern} <id> wsdl:messageExchangePattern <pattern> .
{style} (for each style URI)
<id> wsdl:operationStyle <style> .

Table 2-5. Mapping Interface Fault Components to RDF
Property RDF Form
  (id generated per IRI-References for WSDL 2.0 Components)
<id> rdf:type wsdl:InterfaceFault .
<parentInterfaceId> wsdl:interfaceFault <id> .
{name} <id> rdfs:label "<localPart>" .
{element declaration} <id> wsdl:elementDeclaration <qnameId> .
(for qname mapping see Table 2-2)
{message content model} (for "#any") <id> wsdl:messageContentModel wsdl:AnyContent .
(for "#none") <id> wsdl:messageContentModel wsdl:NoContent .
(for "#other") <id> wsdl:messageContentModel wsdl:OtherContent .
(for "#element") <id> wsdl:messageContentModel wsdl:ElementContent .

Table 2-6. Mapping Interface Message Reference Components to RDF
Property RDF Form
  (id generated per IRI-References for WSDL 2.0 Components)
<id> rdf:type wsdl:InterfaceMessageReference .
<parentInterfaceOpId> wsdl:interfaceMessageReference <id> .
{element declaration} <id> wsdl:elementDeclaration <qnameId> .
(for qname mapping see Table 2-2)
{direction} (for "in") <id> rdf:type wsdl:InputMessage .
(for "out") <id> rdf:type wsdl:OutputMessage .
{message content model} (for "#any") <id> wsdl:messageContentModel wsdl:AnyContent .
(for "#none") <id> wsdl:messageContentModel wsdl:NoContent .
(for "#other") <id> wsdl:messageContentModel wsdl:OtherContent .
(for "#element") <id> wsdl:messageContentModel wsdl:ElementContent .
{message label} <id> wsdl:messageLabel <label> .
(label as defined by the message exchange pattern's mapping to RDF, see section 2.3)

Table 2-7. Mapping Interface Fault Reference Components to RDF
Property RDF Form
  (id generated per IRI-References for WSDL 2.0 Components)
<id> rdf:type wsdl:InterfaceFaultReference .
<parentInterfaceOpId> wsdl:interfaceFaultReference <id> .
{interface fault} <id> wsdl:interfaceFault <faultId> .
(for interface fault mapping see Table 2-5)
{direction} (for "in") <id> rdf:type wsdl:InputMessage .
(for "out") <id> rdf:type wsdl:OutputMessage .
{message label} <id> wsdl:messageLabel <label> .
(label as defined by the message exchange pattern's mapping to RDF, see section 2.3)

2.1.3 Binding classes

WSDL binding components are represented in RDF as instances of the class Binding. To indicate a particular interface for which binding information is specified with this WSDL binding, the particular Interface instance is pointed to using the property binds. Binding types (for example SOAP binding or HTTP binding, as specified in [WSDL 2.0 Adjuncts]) are themselves classes in RDF, so a binding type is indicated by belonging to the appropriate class (using the property rdf:type).

Every binding component has a name, which is a QName. The namespace IRI part of this QName is present before the fragment ID of the component identifier, and the local name is represented in the RDF form as a literal value of the property rdfs:label.

As the structure of bindings follows the structure of interfaces, we represent binding operations and faults using the classes BindingOperation and BindingFault respectively. The Binding points to them using the similarly named properties bindingOperation and bindingFault. Binding operations further contain message and fault references, represented as instances of the classes BindingMessageReference and BindingFaultReference, and pointed to by the properties bindingMessageReference and bindingFaultReference.

Within this structure, each component points to the appropriate component from the interface structure, i.e. BindingOperation instances point to InterfaceOperation instances, BindingFault instances point to InterfaceFault instances and BindingMessageReference and BindingFaultReference instances point to InterfaceMessageReference and InterfaceFaultReference instances. To provide these pointers, we use the property binds between the pairs of components.

Finally, each component is supposed to contain extensions that provide the actual binding information. For the description of handling such extensions see section 2.2 and for the specific bindings included in WSDL 2.0 specification, see sections 2.6 and 2.7.

Table 2-8. Mapping Binding Components to RDF
Property RDF Form
  (id generated per IRI-References for WSDL 2.0 Components)
<id> rdf:type wsdl:Binding .
<parentDescriptionId> wsdl:binding <id> .
{name} <id> rdfs:label "<localPart>" .
{interface} <id> wsdl:binds <interfaceId> .
{type} <id> rdf:type <type> .
{binding operations} (for binding operation mapping see Table 2-9)
{binding faults} (for binding fault mapping see Table 2-10)

Table 2-9. Mapping Binding Operation Components to RDF
Property RDF Form
  (id generated per IRI-References for WSDL 2.0 Components)
<id> rdf:type wsdl:BindingOperation .
<parentBindingId> wsdl:bindingOperation <id> .
{interface operation} <id> wsdl:binds <interfaceOpId> .
{binding message references} (for binding message reference mapping see Table 2-11)
{binding fault references} (for binding fault reference mapping see Table 2-12)

Table 2-10. Mapping Binding Fault Components to RDF
Property RDF Form
  (id generated per IRI-References for WSDL 2.0 Components)
<id> rdf:type wsdl:BindingFault .
<parentBindingId> wsdl:bindingFault <id> .
{interface fault} <id> wsdl:binds <interfaceFaultId> .

Table 2-11. Mapping Binding Message Reference Components to RDF
Property RDF Form
  (id generated per IRI-References for WSDL 2.0 Components)
<id> rdf:type wsdl:BindingMessageReference .
<parentBindingOperationId> wsdl:bindingMessageReference <id> .
{interface message reference} <id> wsdl:binds <interfaceMessageReferenceId> .

Table 2-12. Mapping Binding Fault Reference Components to RDF
Property RDF Form
  (id generated per IRI-References for WSDL 2.0 Components)
<id> rdf:type wsdl:BindingFaultReference .
<parentBindingOperationId> wsdl:bindingFaultReference <id> .
{interface fault reference} <id> wsdl:binds <interfaceFaultReferenceId> .

2.1.4 Service classes

WSDL services are represented in RDF as instances of the class Service. Each instance points to a single interface; for this purpose we reuse the property implements. Also, each service has one or more endpoints, to which it points using the property endpoint.

Services have a name, which is a QName. The namespace URI part of this QName is present before the fragment ID of the component identifier, and the local name is represented in the RDF form as a literal value of the property rdfs:label. Similarly, endpoints have a name, which is an NCName. Its value is also represented in the RDF form as a literal value of the property rdfs:label.

Endpoints are represented as instances of the class Endpoint, with two notable properties: a mandatory single usesBinding property points to the binding used by this endpoint, and an optional single address points to the network resource which actually offers the service.

Table 2-13. Mapping Service Components to RDF
Property RDF Form
  (id generated per IRI-References for WSDL 2.0 Components)
<id> rdf:type wsdl:Service .
<parentDescriptionId> wsdl:service <id> .
{name} <id> rdfs:label "<localPart>" .
{interface} <id> wsdl:implements <interfaceId> .
{endpoints} (for endpoint mapping see Table 2-14)

Table 2-14. Mapping Endpoint Components to RDF
Property RDF Form
  (id generated per IRI-References for WSDL 2.0 Components)
<id> rdf:type wsdl:Endpoint .
<parentServiceId> wsdl:endpoint <id> .
{name} <id> rdfs:label "<name>" .
{binding} <id> wsdl:usesBinding <bindingId> .
{address} <id> wsdl:address <address> .

2.2 Handling Extensions and Documentation

In order to enable evolution and reusability of the language, WSDL 2.0 allows extensions on all components. In fact, there are two types of extensibility in WSDL 2.0: explicit extension points, and XML-based extensions.

Extension points are those places in WSDL where a number of options is defined by the WSDL 2.0 specification, but the list is open. For example, interface operations follow message exchange patterns (MEPs), and while WSDL 2.0 provides some predefined MEPs, new ones can be specified by WSDL 2.0 users. Similarly, WSDL 2.0 specifies two bindings (SOAP and HTTP), but more bindings are expected to be specified in the future, either by the WS-Description Working Group or by any interested third parties. Often, extension points use URIs to refer to the various options, and these URIs are then reflected in the RDF form as the appropriate property values. Additionally, some of the extensions also introduce data that would be useful in the RDF representation, in which case it is the responsibility of the extension designers to describe their mappings to RDF. This document describes the mapping of the extensions defined together with the WSDL 2.0 specification.

Apart from the envisioned extensibility points, WSDL 2.0 allows the XML WSDL documents to contain any "foreign" elements and attributes, so that any extensions, even ones that change the core WSDL semantics, can also be realized. The actual meaning of general WSDL extensions is, by definition, unknown to the core WSDL specification, and it is equally unknown to the RDF mapping (apart from the predefined extensions coming with WSDL 2.0, whose mapping to RDF is described in the following sections). Therefore every extension should specify how it is mapped to RDF. For example, the SOAP and HTTP bindings in WSDL 2.0 add many properties to the core binding components and this document defines how these particular properties are expressed in RDF. The mapping of WSDL extensions to RDF therefore depends on the understanding of those extensions.

In WSDL 2.0, extensions can be marked as mandatory (or required). Such extensions may alter the semantics of the extended components in ways that invalidate the existing semantics. Since the RDF representation of WSDL intends to represent the semantics of the WSDL data, components with required extensions will be mapped to RDF according to the rules of the extension, not according to the rules specified in this document. If a processor that does the mapping of a WSDL document to RDF does not understand a particular mandatory extension (in other words, when it encounters an unknown mandatory extension, it cannot map the component that contains that extension into any generic RDF representation, in other words the component will not be present in the resulting RDF data. This is to avoid confusing processors that do not understand a mandatory extension — RDF encourages the principle of ignoring the unknown parts of an RDF graph (partial understanding) and there is no agreed mechanism of marking some parts as mandatory, therefore if we decided to map the known WSDL according to our rules above, the potential changes introduced by the mandatory unknown extensions could be ignored by some RDF processors, which would violate the way WSDL considers them mandatory.

Unknown optional extensions also cannot be mapped to RDF with any mapping rules defined in this document, because their meaning is unknown. However, the parent component is mapped into RDF as though the unknown optional extension was not present at all. Effectively, this WSDL RDF mapping ignores unknown optional extensions.

In addition to the extensions, all WSDL XML elements can also contain documentation. Such documentation can consist of human-readable text or machine-processible elements and attributes, but it is not modeled in more detail in WSDL 2.0. This WSDL RDF mapping does not represent documentation in the resulting RDF graph, because it would be an XML literal with no explicit meaning, and the XML literal would not be readable enough to serve the purpose of human-readable description.

2.3 Message Exchange Patterns

WSDL 2.0 defines an extensible set of message exchange patterns (MEPs). There are 8 predefined MEPs (three in [WSDL 2.0 Adjuncts] and five in [WSDL 2.0 Additional MEPs]), each following one of the three predefined fault propagation rules. Every WSDL MEP defines a set of message labels by which message references in operations can position themselves within the pattern.

In the RDF representation of WSDL, message exchange patterns are represented as instances of the class MessageExchangePattern. The three predefined fault propagation rules are disjoint subclasses of that class, named NoFaults, FaultReplacesMessage and MessageTriggersFault.

All MEPs are identified by IRIs, and the RDF ontology for WSDL assigns classes to MEPs; for example http://www.w3.org/ns/wsdl/in-only is an instance of the class NoFaults. The message labels, however, are plain string names, and the RDF ontology for WSDL gives each of them an IRI formed by the MEP IRI, the hash sign '#' and the actual message label, and these IRIs are referenced from the MEPs with the property definesMessageLabel. Any newly created MEPs should also provide IRIs for the message labels, as the RDF mapping depends on being able to identify the message labels on interface message references.

The following mapping table only shows the message label URIs defined by the WSDL ontology for the message labels defined by the message exchange patterns from [WSDL 2.0 Adjuncts] and [WSDL 2.0 Additional MEPs].

Table 2-15. Mapping Message Exchange Pattern Labels to RDF
MEP Label Label URI
In-Only In http://www.w3.org/ns/wsdl/in-only#In
Robust In-Only In http://www.w3.org/ns/wsdl/robust-in-only#In
In-Out In http://www.w3.org/ns/wsdl/in-out#In
Out http://www.w3.org/ns/wsdl/in-out#Out
In-Optional-Out In http://www.w3.org/ns/wsdl/in-opt-out#In
Out http://www.w3.org/ns/wsdl/in-opt-out#Out
Out-Only Out http://www.w3.org/ns/wsdl/out-only#Out
Robust Out-Only Out http://www.w3.org/ns/wsdl/robust-out-only#Out
Out-In Out http://www.w3.org/ns/wsdl/out-in#Out
In http://www.w3.org/ns/wsdl/out-in#In
Out-Optional-In Out http://www.w3.org/ns/wsdl/out-opt-in#Out
In http://www.w3.org/ns/wsdl/out-opt-in#In

2.4 Predefined Extensions

WSDL 2.0 Adjuncts contain a single predefined extension, called Operation Safety, which adds a property to interface operation components to indicate whether an interface operation is known to be safe in terms of [Web Architecture].

In the RDF representation of WSDL, we introduce the class SafeInteraction, and we use the Semantic Annotations for WSDL and XML Schema ([SAWSDL]) property modelReference to annotate any InterfaceOperation instance that is asserted to be safe.

Note: the fact that the SAWSDL modelReference RDF property is used in this WSDL RDF mapping does not introduce the dependency that WSDL processors or WSDL RDF mapping implementations would need to understand the SAWSDL extension.

Table 2-16. Mapping Interface Operation Components with Safety to RDF
Property RDF Form
{safety} (only if true) <operationId> sawsdl:modelReference wsdlx:SafeInteraction .

2.5 Operation Styles

WSDL 2.0 predefines 3 operation styles — RPC style, IRI style and Multipart style. These styles are identified with their IRIs, which are, in the RDF ontology, instances of the class OperationStyle.

The RPC style additionally introduces the property {rpc signature}, which is represented in RDF as a sequence of arguments, indicating the direction and element qname. The signature property can be attached to interface operations that follow the RPC style to indicate the parameter order for the operation. The property points to an instance of the class Signature (subclass of rdf:Seq); and every member represents an argument specification. Each argument uses the property elementDeclaration to specify an element, and the rdf:type of an argument indicates its direction (one of the classes InArgument, OutArgument, InOutArgument, ReturnArgument).

Table 2-17. Mapping Interface Operation Components with RPC Signature to RDF
Property RDF Form
{rpc signature} <operationId> wrpc:signature <sigId> .
<sigId> rdf:type wrpc:Signature .
(sigId is a newly generated unique URI)
(for each argument/direction pair) <sigId> rdf:_nnn <argId> .

(argId is a newly generated unique URI)
(_nnn starts from _1 and the number is increased by 1 for each argument)
(for #in arguments) <argId> rdf:type wrpc:InArgument .
(for #out arguments) <argId> rdf:type wrpc:OutArgument .
(for #inout arguments) <argId> rdf:type wrpc:InOutArgument .
(for #return arguments) <argId> rdf:type wrpc:ReturnArgument .
<argId> wsdl:elementDeclaration <qnameId> .
(for qname mapping see Table 2-2)

2.6 SOAP Binding

WSDL bindings that bind to SOAP are identified (using the property rdf:type) as instances of the class http://www.w3.org/ns/wsdl/soap. Every such binding indicates the SOAP version that it uses, this is done with the property version (with a value "1.2", for example, meaning SOAP version 1.2). Every binding also specifies with the property protocol the underlying protocol that is uses.

Each SOAP binding operation specifies the SOAP message exchange pattern it uses — the appropriate URI from the SOAP specification is pointed to using the property soapMEP. The range of this property is the SOAP 1.2 class http://www.w3.org/2006/02/soap12/abstractions#classOfMEPs that contains all the SOAP MEPs. Some bindings (especially those that are not specific to any interface) will rely on defaulting to set the SOAP message exchange pattern, this default is captured using the property defaultSoapMEP.

SOAP binding operations can additionally specify the value of the action parameter (known as SOAP action) for the initial message, using the property action.

Binding faults in the SOAP binding can specify two properties — fault code and fault subcodes. Both fault code and subcodes are QNames, and they are pointed to using the properties faultCode and faultSubcodes. The latter points to an RDF sequence (rdf:Seq) which contains all the subcodes.

At any level within a SOAP binding, components can declare the use of a SOAP module. Required modules are pointed to using the property requiresSOAPModule and optional modules are pointed to using the property offersSOAPModule — both of these properties point directly from the parent component to the SOAP module, as identified by its URI (parameter {ref} of the SOAP Module component).

Message references and faults in SOAP bindings can further declare that they require or offer a specific SOAP headers. To do this, the properties requiresHeader and offersHeader can point to an instance of the class SOAPHeaderBlock, which then uses the property elementDeclaration to specify the exact element that represents the header. Instances of SOAPHeaderBlock can also belong to the class MustUnderstandSOAPHeaderBlock, which means that this SOAP header will be marked as mandatory (mustUnderstand="true") in the message.

Apart from these SOAP-binding-specific properties, the SOAP binding reuses underlying protocol properties, for example some HTTP binding properties when the underlying protocol is HTTP. The following section describes the HTTP binding properties.

Table 2-18. Mapping SOAP Binding Components to RDF
Property RDF Form
{soap mep default} <bindingId> wsoap:defaultSoapMEP <pattern> .
{soap underlying protocol} <bindingId> wsoap:protocol <protocol> .
{soap version} <bindingId> wsoap:version "<version>" .
{soap modules} (for soap module mapping see Table 2-23)

Table 2-19. Mapping SOAP Binding Operation Components to RDF
Property RDF Form
{soap action} <bindingOpId> wsoap:action <action> .
{soap mep} <bindingOpId> wsoap:soapMEP <pattern> .
{soap modules} (for soap module mapping see Table 2-23)

Table 2-20. Mapping SOAP Binding Fault Components to RDF
Property RDF Form
{soap fault code} (only if not "#any") <bindingFaultId> wsoap:faultCode <qnameId> .
(for qname mapping see Table 2-2)
{soap fault subcodes} (only if not "#any")
<bindingFaultId> wsoap:faultSubcodes <subId> .
<subId> rdf:type rdf:Seq .
(for each subcode) <subId> rdf:_nnn <qnameId> .

(subId is a newly generated unique URI)
(_nnn starts from _1 and the number is increased by 1 for each subcode)
(for qname mapping see Table 2-2)
{soap modules} (for soap module mapping see Table 2-23)
{soap headers} (for soap header block mapping see Table 2-24)

Table 2-21. Mapping SOAP Binding Message Reference Components to RDF
Property RDF Form
{soap modules} (for soap module mapping see Table 2-23)
{soap headers} (for soap header block mapping see Table 2-24)

Table 2-22. Mapping SOAP Binding Fault Reference Components to RDF
Property RDF Form
{soap modules} (for soap module mapping see Table 2-23)

Table 2-23. Mapping SOAP Module Components to RDF
Property RDF Form
{ref} (value used below)
{required} (for required) <parentComponentId> wsoap:requiresSOAPModule <ref> .
(for not required) <parentComponentId> wsoap:offersSOAPModule <ref> .

Table 2-24. Mapping SOAP Header Block Components to RDF
Property RDF Form
  (id generated per IRI Identification Of A SOAP Header Block component)
<id> rdf:type wsoap:SOAPHeaderBlock .
{required} (for required) <parentComponentId> wsoap:requiresHeader <id> .
(for not required) <parentComponentId> wsoap:offersHeader <id> .
{mustUnderstand} (only if true) <id> rdf:type wsoap:MustUnderstandSOAPHeaderBlock .
{element declaration} <id> wsdl:elementDeclaration <qnameId> .
(for qname mapping see Table 2-2)

2.7 HTTP Binding

WSDL bindings that bind to HTTP are identified as instances of the class http://www.w3.org/ns/wsdl/http.

The HTTP bindings that make use of HTTP cookies, as well as other bindings that reuse HTTP and use cookies, are further identified as instances of the class BindingUsingHTTPCookies.

HTTP binding operations can specify a number of HTTP parameters: operation-specific location (and what to do with parameters that are not serialized in it — ignore uncited), HTTP method, input and output and fault serialization, and query parameter separator. These parameters are represented in RDF with the properties location, locationIgnoreUncited, method, inputSerialization, outputSerialization, faultSerialization and queryParameterSeparator. The HTTP method and query parameter separator can also be specified on the binding level as defaults, especially in bindings that are not specific to any particular interface. Those defaults are preserved using properties defaultMethod and defaultQueryParameterSeparator. The values of all these properties are literals, same as in the XML syntax of WSDL.

Message references and faults in an HTTP binding can specify the use of extra HTTP headers. Required headers are pointed to using the property requiresHeader, whereas optional headers are referenced using the property offersHeader. Both properties point to an instance of the class HTTPHeader. Each HTTPHeader instance has a property headerName that specifies the name of the header, and a property typeDefinition which defines the simple type of the header value.

Message references and faults can also specify the content encoding using the property contentEncoding with a literal string value, as in the XML representation; and binding operations or even bindings may define the default content encoding values using the property defaultContentEncoding. Finally, faults can further specify the HTTP status code they will be accompanies with, using the property errorCode.

Service endpoints that use an HTTP binding can specify access authentication parameters, in particular authentication scheme and realm. These parameters are reflected with the properties authenticationScheme and authenticationRealm with string values.

Table 2-25. Mapping HTTP Binding Components to RDF
Property RDF Form
{http cookies} (only if true) <bindingId> rdf:type whttp:BindingUsingHTTPCookies .
{http content encoding default} <bindingId> whttp:defaultContentEncoding "<coding>" .
{http method default} <bindingId> whttp:defaultMethod "<method>" .
{http query parameter separator default} <bindingId> whttp:defaultQueryParameterSeparator "<separator>" .

Table 2-26. Mapping HTTP Binding Operation Components to RDF
Property RDF Form
{http location} <bindingOpId> whttp:location "<location>" .
{http content encoding default} <bindingOpId> whttp:defaultContentEncoding "<coding>" .
{http input serialization} <bindingOpId> whttp:inputSerialization "<serialization>" .
{http output serialization} <bindingOpId> whttp:outputSerialization "<serialization>" .
{http fault serialization} <bindingOpId> whttp:faultSerialization "<serialization>" .
{http location ignore uncited} <bindingOpId> whttp:locationIgnoreUncited "<ignoreFlag>"^^xs:boolean .
{http method} <bindingOpId> whttp:method "<method>" .
{http query parameter separator} <bindingOpId> whttp:queryParameterSeparator "<separator>" .

Table 2-27. Mapping HTTP Binding Fault Components to RDF
Property RDF Form
{http error status code} (only if not "#any") <bindingFaultId> whttp:errorCode "<code>"^^xs:int .
{http content encoding} <bindingFaultId> whttp:contentEncoding "<coding>" .
{http headers} (for http header mapping see Table 2-30)

Table 2-28. Mapping HTTP Binding Message Reference Components to RDF
Property RDF Form
{http content encoding} <bindingMessageRefId> whttp:contentEncoding "<coding>" .
{http headers} (for http header mapping see Table 2-30)

Table 2-29. Mapping HTTP Endpoint Components to RDF
Property RDF Form
{http authentication realm} <endpointId> whttp:authenticationRealm "<realm>" .
{http authentication scheme} <endpointId> whttp:authenticationScheme "<scheme>" .

Table 2-30. Mapping HTTP Header Block Components to RDF
Property RDF Form
  (id generated per IRI Identification Of A HTTP Header component)
<id> rdf:type whttp:HTTPHeader .
{required} (for required) <parentComponentId> whttp:requiresHeader <id> .
(for not required) <parentComponentId> whttp:offersHeader <id> .
{type definition} <id> wsdl:typeDefinition <qnameId> .
(for qname mapping see Table 2-2)

3. Example WSDL document in RDF form

The following is a listing of the RDF form of the WSDL description of the initial GreatH Web Service (listed as example 2-1) from the WSDL 2.0 primer (in triple notation):

@prefix rdfs:    <http://www.w3.org/2000/01/rdf-schema#> .
@prefix sawsdl:  <http://www.w3.org/ns/sawsdl#> .
@prefix whttp:   <http://www.w3.org/ns/wsdl/http#> .
@prefix wsdl:    <http://www.w3.org/ns/wsdl-rdf#> .
@prefix wsdlx:   <http://www.w3.org/ns/wsdl-extensions#> .
@prefix wsoap:   <http://www.w3.org/ns/wsdl/soap#> .


<http://greath.example.com/2004/wsdl/resSvc#wsdl.description()>
      a     wsdl:Description ;
      wsdl:interface 
            <http://greath.example.com/2004/wsdl/resSvc#wsdl.interface(reservationInterface)> ;
      wsdl:binding 
            <http://greath.example.com/2004/wsdl/resSvc#wsdl.binding(reservationSOAPBinding)> ;
      wsdl:service <http://greath.example.com/2004/wsdl/resSvc#wsdl.service(reservationService)> .



<http://greath.example.com/2004/wsdl/resSvc#wsdl.interface(reservationInterface)>
      a     wsdl:Interface ;
      rdfs:label "reservationInterface" ;
      wsdl:interfaceOperation 
            <http://greath.example.com/2004/wsdl/resSvc#wsdl.interfaceOperation(reservationInterface/opCheckAvailability)> ;
      wsdl:interfaceFault 
            <http://greath.example.com/2004/wsdl/resSvc#wsdl.interfaceFault(reservationInterface/invalidDataFault)> .

<http://greath.example.com/2004/wsdl/resSvc#wsdl.interfaceOperation(reservationInterface/opCheckAvailability)>
      a     wsdl:InterfaceOperation ;
      rdfs:label "opCheckAvailability" ;
      sawsdl:modelReference wsdlx:SafeInteraction ;
      wsdl:interfaceMessageReference 
            <http://greath.example.com/2004/wsdl/resSvc#wsdl.interfaceMessageReference(reservationInterface/opCheckAvailability/In)> ,
            <http://greath.example.com/2004/wsdl/resSvc#wsdl.interfaceMessageReference(reservationInterface/opCheckAvailability/Out)> ; 
      wsdl:interfaceFaultReference 
            <http://greath.example.com/2004/wsdl/resSvc#wsdl.interfaceFaultReference(reservationInterface/opCheckAvailability/Out/invalidDataFault)> ;
      wsdl:messageExchangePattern <http://www.w3.org/ns/wsdl/in-out> ;
      wsdl:operationStyle <http://www.w3.org/ns/wsdl/style/iri> .

<http://greath.example.com/2004/wsdl/resSvc#wsdl.interfaceMessageReference(reservationInterface/opCheckAvailability/In)>
      a     wsdl:InterfaceMessageReference , wsdl:InputMessage ;
      wsdl:elementDeclaration <urn:uuid:ead76f4f-f5bc-4ca7-af8c-460a9c99fa53> ;
      wsdl:messageContentModel wsdl:ElementContent ;
      wsdl:messageLabel <http://www.w3.org/ns/wsdl/in-out#In> .

<urn:uuid:ead76f4f-f5bc-4ca7-af8c-460a9c99fa53>
      a     wsdl:QName ;
      wsdl:localName "checkAvailability" ;
      wsdl:namespace <http://greath.example.com/2004/schemas/resSvc> .

<http://greath.example.com/2004/wsdl/resSvc#wsdl.interfaceMessageReference(reservationInterface/opCheckAvailability/Out)>
      a     wsdl:InterfaceMessageReference , wsdl:OutputMessage ;
      wsdl:elementDeclaration <urn:uuid:3066fc8c-d060-4bc5-a479-44d752de54ac> ;
      wsdl:messageContentModel wsdl:ElementContent ;
      wsdl:messageLabel <http://www.w3.org/ns/wsdl/in-out#Out> .

<urn:uuid:3066fc8c-d060-4bc5-a479-44d752de54ac>
      a     wsdl:QName ;
      wsdl:localName "checkAvailabilityResponse" ;
      wsdl:namespace <http://greath.example.com/2004/schemas/resSvc> .

<http://greath.example.com/2004/wsdl/resSvc#wsdl.interfaceFaultReference(reservationInterface/opCheckAvailability/Out/invalidDataFault)>
      a     wsdl:InterfaceFaultReference , wsdl:OutputMessage ;
      wsdl:interfaceFault 
            <http://greath.example.com/2004/wsdl/resSvc#wsdl.interfaceFault(reservationInterface/invalidDataFault)> ;
      wsdl:messageLabel <http://www.w3.org/ns/wsdl/in-out#Out> .

<http://greath.example.com/2004/wsdl/resSvc#wsdl.interfaceFault(reservationInterface/invalidDataFault)>
      a     wsdl:InterfaceFault ;
      rdfs:label "invalidDataFault" ;
      wsdl:elementDeclaration <urn:uuid:2e72002d-9472-4c4a-a5b8-c6614b609355> ;
      wsdl:messageContentModel wsdl:ElementContent .

<urn:uuid:2e72002d-9472-4c4a-a5b8-c6614b609355>
      a     wsdl:QName ;
      wsdl:localName "invalidDataError" ;
      wsdl:namespace <http://greath.example.com/2004/schemas/resSvc> .



<http://greath.example.com/2004/wsdl/resSvc#wsdl.binding(reservationSOAPBinding)>
      a     wsdl:Binding , <http://www.w3.org/ns/wsdl/soap> ;
      rdfs:label "reservationSOAPBinding" ;
      wsdl:binds 
            <http://greath.example.com/2004/wsdl/resSvc#wsdl.interface(reservationInterface)> ;
      wsdl:bindingOperation 
            <http://greath.example.com/2004/wsdl/resSvc#wsdl.bindingOperation(reservationSOAPBinding/opCheckAvailability)> ;
      wsdl:bindingFault 
            <http://greath.example.com/2004/wsdl/resSvc#wsdl.bindingFault(reservationSOAPBinding/invalidDataFault)> ;
      whttp:defaultQueryParameterSeparator "&" ;
      wsoap:protocol <http://www.w3.org/2003/05/soap/bindings/HTTP/> ;
      wsoap:version "1.2" .

<http://greath.example.com/2004/wsdl/resSvc#wsdl.bindingOperation(reservationSOAPBinding/opCheckAvailability)>
      a     wsdl:BindingOperation ;
      wsdl:binds 
            <http://greath.example.com/2004/wsdl/resSvc#wsdl.interfaceOperation(reservationInterface/opCheckAvailability)> ;
      wsoap:soapMEP <http://www.w3.org/2003/05/soap/mep/soap-response> .

<http://greath.example.com/2004/wsdl/resSvc#wsdl.bindingFault(reservationSOAPBinding/invalidDataFault)>
      a     wsdl:BindingFault ;
      wsdl:binds 
            <http://greath.example.com/2004/wsdl/resSvc#wsdl.interfaceFault(reservationInterface/invalidDataFault)> ;
      wsoap:faultCode <urn:uuid:2fe62e8f-154a-4d6d-ae16-c8c062c5c60b> .

<urn:uuid:2fe62e8f-154a-4d6d-ae16-c8c062c5c60b>
      a     wsdl:QName ;
      wsdl:localName "Sender" ;
      wsdl:namespace <http://www.w3.org/2003/05/soap-envelope> .



<http://greath.example.com/2004/wsdl/resSvc#wsdl.service(reservationService)>
      a     wsdl:Service ;
      rdfs:label "reservationService" ;
      wsdl:endpoint 
            <http://greath.example.com/2004/wsdl/resSvc#wsdl.endpoint(reservationService/reservationEndpoint)> ;
      wsdl:implements 
            <http://greath.example.com/2004/wsdl/resSvc#wsdl.interface(reservationInterface)> .

<http://greath.example.com/2004/wsdl/resSvc#wsdl.endpoint(reservationService/reservationEndpoint)>
      a     wsdl:Endpoint ;
      rdfs:label "reservationEndpoint" ;
      wsdl:address <http://greath.example.com/2004/reservation> ;
      wsdl:usesBinding 
            <http://greath.example.com/2004/wsdl/resSvc#wsdl.binding(reservationSOAPBinding)> .

4. Differences from the WSDL Component Model (Non-Normative)

WSDL defines a component model which consists of components, component properties and sets of components. This document supplies an ontology (i.e., a set of classes, properties, datatypes, and distinguished individuals) for representing WSDL data. This ontology contains axioms which express some of the constraints the WSDL specification imposes on legal sets of WSDL components whether indirectly (via the XML Schema constraints on the infoset which canonically encodes WSDL component models) or directly (via the natural language of the WSDL specs, or the corresponding Z formalization of that language).

RDF, RDFS, and OWL are all less (and differently) expressive than the subset of Z used to formalize the WSDL specification, and are designed for different purposes. In a nutshell, RDF, RDFS, and OWL are relatively small fragments of first order logic, whereas Z encompasses all of first order logic plus set theory. Z supports validation of component models, that is, the acceptance or rejection of component models. This includes type checking, consistency checking, and the verification of integrity constraints. The current set of Semantic Web languages focus on inference and integration of information. To take a simple example, if a Z checkable representation of an Interface component lacks a {name} component property, a Z based validator will complain that that representation is ill formed (given the WSDL specification). An OWL reasoner encountering it will, all other things being equal, conclude that there is such a property, even though the reasoner has not seen it yet. In general, Semantic Web based descriptions of Web services using the WSDL conceptual framework tend to be looser than what the WSDL specification prescribes.

This difference effectively introduces two classes of documents that use the ontology from this document:

  1. RDF documents resulting from translating valid WSDL documents,
  2. arbitrary RDF documents written using the WSDL ontology.

This document focuses on the mapping from valid WSDL component models, and this section in particular talks about differences between a valid component model and its RDF representation.

However, we must note that arbitrary RDF, RDFS, or OWL documents that use the WSDL ontology may describe component models that are incomplete or even illegal. For example, from the point of view of arbitrary RDF documents that use the WSDL ontology, interfaces do not need to belong to any Description. Therefore, the subsections also contain notes about arbitrary RDF documents detailing further differences that an application consuming WSDL RDF data can encounter in documents that are not the direct result of mapping a valid WSDL document into its RDF form. The last subsection (section 4.5) then describes those constraints unenforced by the WSDL, that do not fit in any other subsection above it.

4.1 Component naming

In the RDF representation, all WSDL components are identified with their respective component designators (see [WSDL 2.0 Core Language] appendix C IRI-References for WSDL 2.0 Components), which are URIs generally constructed from the name and namespace of the component and from its parent component hierarchy. The original namespaces are not explicitly modeled in the RDF representation, which intends to convey the semantic meaning of the WSDL component, not the WSDL serialization details; the local names, however, are captured as rdfs:label.

In some situations we can see the RDF representation to be used as an exchange syntax for WSDL. While it is not an intended use, it is possible that in some systems the XML syntax will be lost or inaccessibly hidden in several layers of processing software. Such an application that only receives the RDF form of WSDL can still need to reconstruct the original component names, for example if it uses an API that identifies WSDL operations by their parent interface's QName and the operation name.

The component designators put the names of the components in the fragment identifier part of the resulting URIs. On the Web (see [Web Architecture]), the interpretation of fragment identifiers is defined by the MIME media type of the representation of the resource identified by the URI without the fragment identifier. In our particular case, we expect that the namespace URI identifies an application/wsdl+xml document so that the constructed component designator fragment identifiers can have their intended meaning. An application working with the RDF representation of WSDL can reconstruct the names of the components by reversing the process that resulted in the component designator, for example for a URI http://example.com/service#wsdl.interfaceOperation(TicketInterface/BookTicket) we could reconstruct that the name of the interface is "TicketInterface" in the namespace http://example.com/service and that the operation is named "BookTicket".

Such decomposition is only valid, though, if the URI http://example.com/service identifies a document of MIME media type application/wsdl+xml, as explained above. Checking the MIME media type of every resource identified by a URI in an RDF graph could be prohibitively slow for some applications, therefore it may be practical (albeit not entirely correct) simply to assume the correct media type and deconstruct the component names without the preceding media type check.

Note about arbitrary RDF documents: in general, it is possible to assert about any resource (identified by any kind of URI) that it is, for example, a WSDL operation, and if an application tries to deconstruct that URI according to WSDL component designator specification, it may find that the URI does not conform to the syntax (e.g. http://example.com/service/operation) or, by accident or malice, it does conform to the syntax but does not contain the correct data (e.g. http://example.com/service#wsdl.interface(TicketInterface) that is marked to be a WSDL operation, not an interface as it would seem).

4.2 Documents, imports and includes

In the XML syntax for WSDL, documents can be included and imported, allowing for modularization while keeping the ability to validate that a WSDL document (plus all the includes and imports) does not use any unknown components. Such modularization is lost when the WSDL files are parsed into a component model, therefore a straigtforward transformation of such a component model into RDF will result in a single RDF document.

As one exception, all references to element declarations and type definitions from XML Schema are done in the RDF representation by QName and we expect the applications processing this representation to have means of locating the appropriate descriptions for these QNames. We do not model XML Schema (or any other) type definitions and element declarations in this ontology.

Note about arbitrary RDF documents: RDF data can be split into any number of pieces, which can be put together by the processing application as appropriate. If a piece of WSDL/RDF description uses an unknown component (e.g. an interface described in one document may extend other interfaces, not described in this document), the application may, if necessary, attempt to locate the description of the unknown component, for example using its identifier IRI. Note that RDF does not provide a standard generic way of including external data, so any inclusion is application-specific.

Additionally, a single RDF document may also contain multiple unrelated Descriptions, that is, it may be an aggregation of many unrelated WSDL documents, and this may have unexpected results if the aggregated WSDL data contains conflicts, i.e. different definitions of components with the same name; especially when dealing with different versions of descriptions of the same entities.

4.3 Component references

In the XML representation of WSDL, components are referred to using their names, and extensibility points usually use IRIs to identify things. All these references are, from XML point of view, literals. In the RDF representation, on the other hand, most references are direct, using the particular identifier IRIs, not represented as literals. For example, most instances representing components are identified with their component designators (see [WSDL 2.0 Core Language] appendix C IRI-References for WSDL 2.0 Components) and all references point directly there — an operation within a binding points to its respective interface operation using the interface operation component designator IRI, whereas in the XML syntax the operations are correlated using the operation QName.

As a notable exception, references to type definitions and element declarations (usually from XML Schema) are represented as instances of our class QName, with local part represented as literal and the namespace as a resource. This might change if a standard RDF representation for XML Schema element declarations and type definitions is developed — then direct references to the URIs used in that representation would be used.

Additionally, the SOAP Module component in WSDL is really only a pointer: it has a literal property {ref} that contains an IRI identifying the SOAP module, and a property {required} that indicates whether the use of that SOAP module is required. While this component can contain documentation and extensions in WSDL, we chose to represent it as a direct link from the parent component to the target module, as the indirection seems to add very little value and introduces naming difficulties — we would have to have class for the SOAP Module component which would contain a pointer to SOAP Module. The requiredness of the SOAP Module is expressed in the type of the property that points to the module — the parent component either offersSOAPModule or requiresSOAPModule.

4.4 Representing properties with classes

In certain cases the RDF mapping introduces classes where the WSDL 2.0 component model has a property with a limited number of values. For instance, instead of having a direction property on message and fault references, with the values either "in" or "out", we introduce two classes, InputMessage and OutputMessage, and the direction of a particular message or fault reference is then indicated by belonging to either of these classes. Similarly, binding types are classes and the type of a particular binding is indicated by its belonging to that class; we predefine the two classes for the two bindings that are part of WSDL 2.

4.5 Other WSDL restrictions not enforced by the ontology

As already mentioned, the validation-oriented WSDL specification and especially its Z formalization capture a number of restrictions and limitations that are not expressed in the RDF ontology. None of these restrictions or limitations can be violated when a valid WSDL document is mapped into its RDF form. When the RDF data is directly manipulated, for example merged with other RDF data (for example other WSDL documents mapped into RDF), or when new data is created that uses the WSDL ontology, further significant WSDL constraints might be violated:

5. References

[OWL]
OWL Web Ontology Language Reference, M. Dean and G. Schreiber, Editors. World Wide Web Consortium, 10 February 2004 . This version of OWL Web Ontology Language Reference Recommendation is http://www.w3.org/TR/2004/REC-owl-ref-20040210/. The latest version of OWL Web Ontology Language Reference is available at http://www.w3.org/TR/owl-ref/
[RDF]
Resource Description Framework (RDF): Concepts and Abstract Syntax, G. Klyne and J. J. Carroll, Editors. World Wide Web Consortium, 10 February 2004. This version of Resource Description Framework (RDF): Concepts and Abstract Syntax is http://www.w3.org/TR/2004/REC-rdf-concepts-20040210/. The lastest version of Resource Description Framework (RDF): Concepts and Abstract Syntax is available at http://www.w3.org/TR/rdf-concepts/
[SAWSDL]
Semantic Annotations for WSDL and XML Schema, J. Farrell and H. Lausen, Editors. World Wide Web Consortium, 10 April 2007. This version of the "Semantic Annotations for WSDL and XML Schema" Specification is available is available at http://www.w3.org/TR/2007/WD-sawsdl-20070410/. The latest version of "Semantic Annotations for WSDL and XML Schema" is available at http://www.w3.org/TR/sawsdl/.
[Web Architecture]
Architecture of the World Wide Web, Volume One, I. Jacobs and N. Walsh, Editors. World Wide Web Consortium, 15 December 2004. This version of the Architecture of the World Wide Web, Volume One Recommendation is http://www.w3.org/TR/2004/REC-webarch-20041215/. The lastest version of Architecture of the World Wide Web, Volume One is available at http://www.w3.org/TR/webarch/
[WSDL 2.0 Core Language]
Web Services Description Language (WSDL) Version 2.0 Part 1: Core Language, R. Chinnici, M. Gudgin, J-J. Moreau, S. Weerawarana, Editors. World Wide Web Consortium, 23 May 2007. This version of the "Web Services Description Language (WSDL) Version 2.0 Part 1: Core Language" Specification is available is available at http://www.w3.org/TR/2007/PR-wsdl20-20070523. The latest version of "Web Services Description Language (WSDL) Version 2.0 Part 1: Core Language" is available at http://www.w3.org/TR/wsdl20/.
[WSDL 2.0 Adjuncts]
Web Services Description Language (WSDL) Version 2.0 Part 2: Adjuncts, R. Chinnici, H. Haas, A. Lewis, J-J. Moreau, D. Orchard, S. Weerawarana, Editors. World Wide Web Consortium, 23 May 2007. This version of the "Web Services Description Language (WSDL) Version 2.0 Part 2: Adjuncts" Specification is available at http://www.w3.org/TR/2007/PR-wsdl20-adjuncts-20070523. The latest version of "Web Services Description Language (WSDL) Version 2.0 Part 2: Adjuncts" is available at http://www.w3.org/TR/wsdl20-adjuncts/.
[WSDL 2.0 Additional MEPs]
Web Services Description Language (WSDL) Version 2.0: Additional MEPs, A. Lewis, Editor. World Wide Web Consortium, 23 May 2007. This version of the "Web Services Description Language (WSDL) Version 2.0: Additional MEPs" Specification is available at http://www.w3.org/TR/2007/WD-wsdl20-additional-meps-20070523. The latest version of "Web Services Description Language (WSDL) Version 2.0: Additional MEPs" is available at http://www.w3.org/TR/wsdl20-additional-meps/.
[XML Namespaces]
Namespaces in XML 1.0 (Second Edition), T. Bray, D. Hollander, A. Layman, and R. Tobin, Editors. World Wide Web Consortium, 14 January 1999, revised 16 August 2006. This version of the Namespaces in XML Recommendation is http://www.w3.org/TR/2006/REC-xml-names-20060816. The latest version of Namespaces in XML is available at http://www.w3.org/TR/xml-names.

Appendix A: The OWL Ontology Source

Note that the ontology is also available in a separate RDF file.

<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
         xmlns:owl="http://www.w3.org/2002/07/owl#"
         xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#"
         xmlns:wsdl="http://www.w3.org/ns/wsdl-rdf#"
         xmlns:xml="http://www.w3.org/XML/1998/namespace"
         xml:base="http://www.w3.org/ns/wsdl-rdf">


<owl:Ontology rdf:about="">
</owl:Ontology>

<owl:Class rdf:about="#Binding">
  <rdfs:comment>The type of a binding is indicated with rdf:type</rdfs:comment>
</owl:Class>

<owl:Class rdf:about="#BindingFault">
</owl:Class>

<owl:Class rdf:about="#BindingFaultReference">
</owl:Class>

<owl:Class rdf:about="#BindingMessageReference">
</owl:Class>

<owl:Class rdf:about="#BindingOperation">
</owl:Class>

<owl:Class rdf:about="#Description">
</owl:Class>

<owl:Class rdf:about="#Endpoint">
  <rdfs:subClassOf>
    <owl:Restriction>
      <owl:onProperty rdf:resource="#address"/>
      <owl:maxCardinality rdf:datatype="http://www.w3.org/2001/XMLSchema#nonNegativeInteger">1</owl:maxCardinality>
    </owl:Restriction>
  </rdfs:subClassOf>
  <rdfs:subClassOf>
    <owl:Restriction>
      <owl:onProperty rdf:resource="#usesBinding"/>
      <owl:cardinality rdf:datatype="http://www.w3.org/2001/XMLSchema#nonNegativeInteger">1</owl:cardinality>
    </owl:Restriction>
  </rdfs:subClassOf>
</owl:Class>

<owl:Class rdf:about="#Interface">
  <rdfs:label>WDSL Interface</rdfs:label>
</owl:Class>

<owl:Class rdf:about="#InterfaceFault">
  <rdfs:subClassOf>
    <owl:Restriction>
      <owl:onProperty rdf:resource="#messageContentModel"/>
      <owl:cardinality rdf:datatype="http://www.w3.org/2001/XMLSchema#nonNegativeInteger">1</owl:cardinality>
    </owl:Restriction>
  </rdfs:subClassOf>
</owl:Class>

<owl:Class rdf:about="#InterfaceFaultReference">
</owl:Class>

<owl:Class rdf:about="#InterfaceMessageReference">
  <rdfs:subClassOf>
    <owl:Restriction>
      <owl:onProperty rdf:resource="#messageContentModel"/>
      <owl:cardinality rdf:datatype="http://www.w3.org/2001/XMLSchema#nonNegativeInteger">1</owl:cardinality>
    </owl:Restriction>
  </rdfs:subClassOf>
</owl:Class>

<owl:Class rdf:about="#InputMessage">
  <rdfs:comment>To be used by message references and fault references instead of direction property</rdfs:comment>
  <owl:disjointWith rdf:resource="#OutputMessage"/>
</owl:Class>

<owl:Class rdf:about="#OutputMessage">
  <rdfs:comment>To be used by message references and fault references instead of direction property</rdfs:comment>
</owl:Class>

<owl:Class rdf:about="#InterfaceOperation">
  <rdfs:subClassOf>
    <owl:Restriction>
      <owl:onProperty rdf:resource="#messageExchangePattern"/>
      <owl:cardinality rdf:datatype="http://www.w3.org/2001/XMLSchema#nonNegativeInteger">1</owl:cardinality>
    </owl:Restriction>
  </rdfs:subClassOf>
</owl:Class>

<owl:Class rdf:about="#Service">
  <rdfs:subClassOf>
    <owl:Restriction>
      <owl:onProperty rdf:resource="#implements"/>
      <owl:cardinality rdf:datatype="http://www.w3.org/2001/XMLSchema#nonNegativeInteger">1</owl:cardinality>
    </owl:Restriction>
  </rdfs:subClassOf>
</owl:Class>

<owl:Class rdf:about="#MessageExchangePattern">
</owl:Class>

<owl:Class rdf:about="#MessageLabel">
</owl:Class>

<owl:ObjectProperty rdf:about="#definesMessageLabel">
  <rdfs:domain rdf:resource="#MessageExchangePattern"/>
  <rdfs:range  rdf:resource="#MessageLabel"/>
</owl:ObjectProperty>

<owl:ObjectProperty rdf:about="#address">
  <rdfs:domain rdf:resource="#Endpoint"/>
</owl:ObjectProperty>

<owl:ObjectProperty rdf:about="#binding">
  <rdfs:range  rdf:resource="#Binding"/>
  <rdfs:comment>To be used for pointing to a Binding from Description</rdfs:comment>
</owl:ObjectProperty>

<owl:ObjectProperty rdf:about="#usesBinding">
  <rdfs:domain rdf:resource="#Endpoint"/>
  <rdfs:range  rdf:resource="#Binding"/>
  <rdfs:comment>To be used for pointing to a Binding from Endpoint</rdfs:comment>
</owl:ObjectProperty>

<owl:ObjectProperty rdf:about="#bindingFault">
  <rdfs:range  rdf:resource="#BindingFault"/>
</owl:ObjectProperty>

<owl:ObjectProperty rdf:about="#bindingOperation">
  <rdfs:range  rdf:resource="#BindingOperation"/>
</owl:ObjectProperty>

<owl:ObjectProperty rdf:about="#bindingMessageReference"> 
  <rdfs:range  rdf:resource="#BindingMessageReference"/>
</owl:ObjectProperty>

<owl:ObjectProperty rdf:about="#bindingFaultReference"> 
  <rdfs:range  rdf:resource="#BindingFaultReference"/>
</owl:ObjectProperty>

<owl:ObjectProperty rdf:about="#typeDefinition">
  <rdfs:range  rdf:resource="#QName"/>
</owl:ObjectProperty>

<owl:ObjectProperty rdf:about="#elementDeclaration">
  <rdfs:range  rdf:resource="#QName"/>
</owl:ObjectProperty>

<owl:ObjectProperty rdf:about="#endpoint"> 
  <rdfs:range  rdf:resource="#Endpoint"/>
</owl:ObjectProperty>

<owl:ObjectProperty rdf:about="#extends">
  <rdfs:comment>
    points from an interface to an interface directly extended by it
  </rdfs:comment>
  <rdfs:range  rdf:resource="#Interface"/>
  <rdfs:domain rdf:resource="#Interface"/>
</owl:ObjectProperty>

<owl:ObjectProperty rdf:about="#implements"> 
  <rdfs:comment>
    points from a service to the interface that the service implements
  </rdfs:comment>
  <rdfs:domain rdf:resource="#Service"/>
  <rdfs:range  rdf:resource="#Interface"/>
</owl:ObjectProperty>

<owl:Class rdf:about="#QName">
  <rdfs:subClassOf>
    <owl:Restriction>
      <owl:onProperty rdf:resource="#localName"/>
      <owl:cardinality rdf:datatype="http://www.w3.org/2001/XMLSchema#nonNegativeInteger">1</owl:cardinality>
    </owl:Restriction>
  </rdfs:subClassOf>
  <rdfs:subClassOf>
    <owl:Restriction>
      <owl:onProperty rdf:resource="#namespace"/>
      <owl:cardinality rdf:datatype="http://www.w3.org/2001/XMLSchema#nonNegativeInteger">1</owl:cardinality>
    </owl:Restriction>
  </rdfs:subClassOf>
</owl:Class>

<owl:DatatypeProperty rdf:about="#localName"> 
  <rdfs:range  rdf:resource="http://www.w3.org/2001/XMLSchema#NCName"/>
</owl:DatatypeProperty>

<owl:ObjectProperty rdf:about="#namespace"> 
</owl:ObjectProperty>

<owl:ObjectProperty rdf:about="#interface">
  <rdfs:range  rdf:resource="#Interface"/>
</owl:ObjectProperty>

<owl:ObjectProperty rdf:about="#interfaceFault">
  <rdfs:range  rdf:resource="#InterfaceFault"/>
</owl:ObjectProperty>

<owl:ObjectProperty rdf:about="#interfaceFaultReference">
  <rdfs:range  rdf:resource="#InterfaceFaultReference"/>
</owl:ObjectProperty>

<owl:ObjectProperty rdf:about="#interfaceMessageReference">
  <rdfs:range  rdf:resource="#InterfaceMessageReference"/>
</owl:ObjectProperty>

<owl:ObjectProperty rdf:about="#binds">
  <rdfs:comment>
    points from a binding component (or any sub-component) to the respective
    interface component (or sub-component)
  </rdfs:comment>
</owl:ObjectProperty>

<owl:ObjectProperty rdf:about="#operationStyle">
  <rdfs:domain rdf:resource="#InterfaceOperation"/>
  <rdfs:range  rdf:resource="#OperationStyle"/>
  <rdfs:comment>
    points to one style this operation conforms to (can be used multiple times
    to point to multiple styles)
  </rdfs:comment>
</owl:ObjectProperty>

<owl:Class rdf:about="#OperationStyle">
</owl:Class>

<owl:ObjectProperty rdf:about="#interfaceOperation">
  <rdfs:range  rdf:resource="#InterfaceOperation"/>
  <rdfs:comment>
    used on interface to link to an operation
  </rdfs:comment>
</owl:ObjectProperty>

<owl:ObjectProperty rdf:about="#messageContentModel">
  <rdfs:range  rdf:resource="#MessageContentModel"/>
</owl:ObjectProperty>

<owl:Class rdf:about="#MessageContentModel">
  <owl:oneOf rdf:parseType="Collection">
      <wsdl:MessageContentModel rdf:about="#AnyContent"/>
      <wsdl:MessageContentModel rdf:about="#NoContent"/>
      <wsdl:MessageContentModel rdf:about="#ElementContent"/>
      <wsdl:MessageContentModel rdf:about="#OtherContent"/>
  </owl:oneOf>
</owl:Class>

<owl:ObjectProperty rdf:about="#messageExchangePattern">
  <rdfs:range  rdf:resource="#MessageExchangePattern"/>
</owl:ObjectProperty>

<owl:ObjectProperty rdf:about="#messageLabel">
  <rdfs:range  rdf:resource="#MessageLabel"/>
</owl:ObjectProperty>

<owl:ObjectProperty rdf:about="#service">
  <rdfs:range  rdf:resource="#Service"/>
</owl:ObjectProperty>


<!-- part 2: message exchange patterns -->

<owl:Class rdf:about="#NoFaults">
  <rdfs:subClassOf rdf:resource="#MessageExchangePattern" />
  <owl:disjointWith rdf:resource="#FaultReplacesMessage"/>
  <owl:disjointWith rdf:resource="#MessageTriggersFault"/>
</owl:Class>

<owl:Class rdf:about="#FaultReplacesMessage">
  <rdfs:subClassOf rdf:resource="#MessageExchangePattern" />
  <owl:disjointWith rdf:resource="#MessageTriggersFault"/>
</owl:Class>

<owl:Class rdf:about="#MessageTriggersFault">
  <rdfs:subClassOf rdf:resource="#MessageExchangePattern" />
</owl:Class>

<wsdl:NoFaults rdf:about="http://www.w3.org/ns/wsdl/in-only">
  <wsdl:definesMessageLabel>
    <wsdl:MessageLabel rdf:about="http://www.w3.org/ns/wsdl/in-only#In"/>
  </wsdl:definesMessageLabel>
</wsdl:NoFaults>

<wsdl:NoFaults rdf:about="http://www.w3.org/ns/wsdl/out-only">
  <wsdl:definesMessageLabel>
    <wsdl:MessageLabel rdf:about="http://www.w3.org/ns/wsdl/out-only#Out"/>
  </wsdl:definesMessageLabel>
</wsdl:NoFaults>

<wsdl:MessageTriggersFault rdf:about="http://www.w3.org/ns/wsdl/robust-in-only">
  <wsdl:definesMessageLabel>
    <wsdl:MessageLabel rdf:about="http://www.w3.org/ns/wsdl/robust-in-only#In"/>
  </wsdl:definesMessageLabel>
</wsdl:MessageTriggersFault>

<wsdl:MessageTriggersFault rdf:about="http://www.w3.org/ns/wsdl/in-opt-out">
  <wsdl:definesMessageLabel>
    <wsdl:MessageLabel rdf:about="http://www.w3.org/ns/wsdl/in-opt-out#In"/>
  </wsdl:definesMessageLabel>
  <wsdl:definesMessageLabel>
    <wsdl:MessageLabel rdf:about="http://www.w3.org/ns/wsdl/in-opt-out#Out"/>
  </wsdl:definesMessageLabel>
</wsdl:MessageTriggersFault>

<wsdl:MessageTriggersFault rdf:about="http://www.w3.org/ns/wsdl/robust-out-only">
  <wsdl:definesMessageLabel>
    <wsdl:MessageLabel rdf:about="http://www.w3.org/ns/wsdl/robust-out-only#Out"/>
  </wsdl:definesMessageLabel>
</wsdl:MessageTriggersFault>

<wsdl:MessageTriggersFault rdf:about="http://www.w3.org/ns/wsdl/out-opt-in">
  <wsdl:definesMessageLabel>
    <wsdl:MessageLabel rdf:about="http://www.w3.org/ns/wsdl/out-opt-in#Out"/>
  </wsdl:definesMessageLabel>
  <wsdl:definesMessageLabel>
    <wsdl:MessageLabel rdf:about="http://www.w3.org/ns/wsdl/out-opt-in#In"/>
  </wsdl:definesMessageLabel>
</wsdl:MessageTriggersFault>

<wsdl:FaultReplacesMessage rdf:about="http://www.w3.org/ns/wsdl/in-out">
  <wsdl:definesMessageLabel>
    <wsdl:MessageLabel rdf:about="http://www.w3.org/ns/wsdl/in-out#In"/>
  </wsdl:definesMessageLabel>
  <wsdl:definesMessageLabel>
    <wsdl:MessageLabel rdf:about="http://www.w3.org/ns/wsdl/in-out#Out"/>
  </wsdl:definesMessageLabel>
</wsdl:FaultReplacesMessage>

<wsdl:FaultReplacesMessage rdf:about="http://www.w3.org/ns/wsdl/out-in">
  <wsdl:definesMessageLabel>
    <wsdl:MessageLabel rdf:about="http://www.w3.org/ns/wsdl/out-in#Out"/>
  </wsdl:definesMessageLabel>
  <wsdl:definesMessageLabel>
    <wsdl:MessageLabel rdf:about="http://www.w3.org/ns/wsdl/out-in#In"/>
  </wsdl:definesMessageLabel>
</wsdl:FaultReplacesMessage>

<!-- part 2: safety -->

<owl:Class rdf:about="http://www.w3.org/ns/wsdl-extensions#SafeInteraction">
  <rdfs:comment>
    Class representing safe interactions as defined in Web Architecture at W3C.
  </rdfs:comment>
</owl:Class>

<!-- part 2: operation styles -->

<wsdl:OperationStyle rdf:about="http://www.w3.org/ns/wsdl/style/rpc">
  <rdfs:comment>RPC operation style</rdfs:comment>
</wsdl:OperationStyle>

<owl:DatatypeProperty rdf:about="http://www.w3.org/ns/wsdl/rpc#signature">
  <rdfs:domain rdf:resource="#InterfaceOperation"/>
  <rdfs:range  rdf:resource="http://www.w3.org/ns/wsdl/rpc#Signature"/>
</owl:DatatypeProperty>

<owl:Class rdf:about="http://www.w3.org/ns/wsdl/rpc#Signature">
  <rdfs:comment>represents an RDF signature, an ordered sequence of Argument instances</rdfs:comment>
  <rdfs:subClassOf rdf:resource="http://www.w3.org/1999/02/22-rdf-syntax-ns#Seq"/>
</owl:Class>

<owl:Class rdf:about="http://www.w3.org/ns/wsdl/rpc#Argument">
  <rdfs:comment>An RPC signature argument, with elementDeclaration; 
    the direction is indicated by the split into subclasses InArgument,
    OutArgument, InOutArgument, ReturnArgument</rdfs:comment>
  <rdfs:subClassOf>
    <owl:Restriction>
      <owl:onProperty rdf:resource="#elementDeclaration"/>
      <owl:cardinality rdf:datatype="http://www.w3.org/2001/XMLSchema#nonNegativeInteger">1</owl:cardinality>
    </owl:Restriction>
  </rdfs:subClassOf>
</owl:Class>

<owl:Class rdf:about="http://www.w3.org/ns/wsdl/rpc#InArgument">
  <rdfs:comment>An RPC signature argument, with elementDeclaration and direction #in</rdfs:comment>
  <rdfs:subClassOf rdf:resource="http://www.w3.org/ns/wsdl/rpc#Argument"/>
</owl:Class>

<owl:Class rdf:about="http://www.w3.org/ns/wsdl/rpc#OutArgument">
  <rdfs:comment>An RPC signature argument, with elementDeclaration and direction #out</rdfs:comment>
  <rdfs:subClassOf rdf:resource="http://www.w3.org/ns/wsdl/rpc#Argument"/>
</owl:Class>

<owl:Class rdf:about="http://www.w3.org/ns/wsdl/rpc#InOutArgument">
  <rdfs:comment>An RPC signature argument, with elementDeclaration and direction #inout</rdfs:comment>
  <rdfs:subClassOf rdf:resource="http://www.w3.org/ns/wsdl/rpc#Argument"/>
</owl:Class>

<owl:Class rdf:about="http://www.w3.org/ns/wsdl/rpc#ReturnArgument">
  <rdfs:comment>An RPC signature argument, with elementDeclaration and direction #return</rdfs:comment>
  <rdfs:subClassOf rdf:resource="http://www.w3.org/ns/wsdl/rpc#Argument"/>
</owl:Class>

<wsdl:OperationStyle rdf:about="http://www.w3.org/ns/wsdl/style/iri">
  <rdfs:comment>IRI operation style</rdfs:comment>
</wsdl:OperationStyle>

<wsdl:OperationStyle rdf:about="http://www.w3.org/ns/wsdl/style/multipart">
  <rdfs:comment>multipart operation style</rdfs:comment>
</wsdl:OperationStyle>



<!-- part 2: bindings -->

<!-- SOAP binding -->

<owl:Class rdf:about="http://www.w3.org/ns/wsdl/soap">
  <rdfs:comment>WSDL 2 SOAP binding</rdfs:comment>
  <rdfs:subClassOf rdf:resource="#Binding"/>
  <rdfs:subClassOf>
    <owl:Restriction>
      <owl:onProperty rdf:resource="http://www.w3.org/ns/wsdl/soap#version"/>
      <owl:cardinality rdf:datatype="http://www.w3.org/2001/XMLSchema#nonNegativeInteger">1</owl:cardinality>
    </owl:Restriction>
  </rdfs:subClassOf>
  <rdfs:subClassOf>
    <owl:Restriction>
      <owl:onProperty rdf:resource="http://www.w3.org/ns/wsdl/soap#protocol"/>
      <owl:cardinality rdf:datatype="http://www.w3.org/2001/XMLSchema#nonNegativeInteger">1</owl:cardinality>
    </owl:Restriction>
  </rdfs:subClassOf>
</owl:Class>

<owl:DatatypeProperty rdf:about="http://www.w3.org/ns/wsdl/soap#version">
  <rdfs:comment>
    indicates what version of SOAP is used by the binding, usually "1.2"
  </rdfs:comment>
  <rdfs:range  rdf:resource="http://www.w3.org/2001/XMLSchema#string"/>
</owl:DatatypeProperty>

<owl:ObjectProperty rdf:about="http://www.w3.org/ns/wsdl/soap#protocol">
  <rdfs:comment>
    indicates the underlying protocol used by a binding
  </rdfs:comment>
</owl:ObjectProperty>

<owl:ObjectProperty rdf:about="http://www.w3.org/ns/wsdl/soap#faultCode">
  <rdfs:comment>
    indicates the fault code of a binding fault
  </rdfs:comment>
  <rdfs:range  rdf:resource="#QName"/>
</owl:ObjectProperty>

<owl:ObjectProperty rdf:about="http://www.w3.org/ns/wsdl/soap#faultSubcodes">
  <rdfs:comment>
    indicates the fault subcodes of a binding fault; there can be multiple
    subcodes, the range is a sequence whose members are qnames
  </rdfs:comment>
  <rdfs:range  rdf:resource="http://www.w3.org/1999/02/22-rdf-syntax-ns#Seq"/>
</owl:ObjectProperty>

<owl:ObjectProperty rdf:about="http://www.w3.org/ns/wsdl/soap#soapMEP">
  <rdfs:comment>
    indicates the SOAP MEP this binding operation uses
  </rdfs:comment>
  <rdfs:range rdf:resource="http://www.w3.org/2006/02/soap12/abstractions#classOfMEPs"/>
</owl:ObjectProperty>

<owl:ObjectProperty rdf:about="http://www.w3.org/ns/wsdl/soap#defaultSoapMEP">
  <rdfs:comment>
    indicates the default SOAP MEP this binding's operations use
  </rdfs:comment>
  <rdfs:range rdf:resource="http://www.w3.org/2006/02/soap12/abstractions#classOfMEPs"/>
</owl:ObjectProperty>

<owl:Class rdf:about="http://www.w3.org/2006/02/soap12/abstractions#classOfMEPs">
</owl:Class>

<rdf:Description rdf:about="http://www.w3.org/2003/05/soap/mep/request-response/">
  <rdf:type rdf:resource="http://www.w3.org/2006/02/soap12/abstractions#classOfMEPs"/>
</rdf:Description>

<rdf:Description rdf:about="http://www.w3.org/2003/05/soap/mep/soap-response/">
  <rdf:type rdf:resource="http://www.w3.org/2006/02/soap12/abstractions#classOfMEPs"/>
</rdf:Description>

<owl:ObjectProperty rdf:about="http://www.w3.org/ns/wsdl/soap#action">
  <rdfs:comment>
    indicates the SOAP action this binding operation uses
  </rdfs:comment>
</owl:ObjectProperty>

<owl:ObjectProperty rdf:about="http://www.w3.org/ns/wsdl/soap#offersSOAPModule">
  <rdfs:comment>
    indicates the SOAP module by its identifier URI
  </rdfs:comment>
</owl:ObjectProperty>

<owl:ObjectProperty rdf:about="http://www.w3.org/ns/wsdl/soap#requiresSOAPModule">
  <rdfs:comment>
    indicates the SOAP module by its identifier URI
  </rdfs:comment>
</owl:ObjectProperty>

<owl:ObjectProperty rdf:about="http://www.w3.org/ns/wsdl/soap#offersHeader">
  <rdfs:range  rdf:resource="http://www.w3.org/ns/wsdl/soap#SOAPHeaderBlock"/>
</owl:ObjectProperty>

<owl:ObjectProperty rdf:about="http://www.w3.org/ns/wsdl/soap#requiresHeader">
  <rdfs:range  rdf:resource="http://www.w3.org/ns/wsdl/soap#SOAPHeaderBlock"/>
</owl:ObjectProperty>

<owl:Class rdf:about="http://www.w3.org/ns/wsdl/soap#SOAPHeaderBlock">
  <rdfs:comment>
    a SOAP header
  </rdfs:comment>
  <rdfs:subClassOf>
    <owl:Restriction>
      <owl:onProperty rdf:resource="#elementDeclaration"/>
      <owl:cardinality rdf:datatype="http://www.w3.org/2001/XMLSchema#nonNegativeInteger">1</owl:cardinality>
    </owl:Restriction>
  </rdfs:subClassOf>
</owl:Class>

<owl:Class rdf:about="http://www.w3.org/ns/wsdl/soap#MustUnderstandSOAPHeaderBlock">
  <rdfs:subClassOf rdf:resource="http://www.w3.org/ns/wsdl/soap#SOAPHeaderBlock" />
  <rdfs:comment>
    a SOAP header that must be marked as mustUnderstand by the sender
  </rdfs:comment>
</owl:Class>

<!-- HTTP binding -->

<owl:Class rdf:about="http://www.w3.org/ns/wsdl/http">
  <rdfs:comment>WSDL 2 HTTP binding</rdfs:comment>
  <rdfs:subClassOf rdf:resource="#Binding"/>
</owl:Class>

<owl:DatatypeProperty rdf:about="http://www.w3.org/ns/wsdl/http#location">
  <rdfs:comment>
    defines the location for an operation, relative to the address of the
    service; this is the only URI-valued property modeled as datatype
    property because the URI is not meant as pointer to a resource
  </rdfs:comment>
  <rdfs:range  rdf:resource="http://www.w3.org/2001/XMLSchema#anyURI"/>
</owl:DatatypeProperty>

<owl:DatatypeProperty rdf:about="http://www.w3.org/ns/wsdl/http#locationIgnoreUncited">
  <rdfs:range  rdf:resource="http://www.w3.org/2001/XMLSchema#boolean"/>
</owl:DatatypeProperty>

<owl:DatatypeProperty rdf:about="http://www.w3.org/ns/wsdl/http#defaultMethod">
  <rdfs:comment>
    declares the default HTTP method used by this binding's operations
  </rdfs:comment>
  <rdfs:range  rdf:resource="http://www.w3.org/2001/XMLSchema#string"/>
</owl:DatatypeProperty>

<owl:DatatypeProperty rdf:about="http://www.w3.org/ns/wsdl/http#method">
  <rdfs:comment>
    declares the HTTP method used by this operation
  </rdfs:comment>
  <rdfs:range  rdf:resource="http://www.w3.org/2001/XMLSchema#string"/>
</owl:DatatypeProperty>

<owl:DatatypeProperty rdf:about="http://www.w3.org/ns/wsdl/http#inputSerialization">
  <rdfs:comment>
    declares the media type of the input message of an operation
  </rdfs:comment>
  <rdfs:range  rdf:resource="http://www.w3.org/2001/XMLSchema#string"/>
</owl:DatatypeProperty>

<owl:DatatypeProperty rdf:about="http://www.w3.org/ns/wsdl/http#outputSerialization">
  <rdfs:comment>
    declares the media type of the output message of an operation
  </rdfs:comment>
  <rdfs:range  rdf:resource="http://www.w3.org/2001/XMLSchema#string"/>
</owl:DatatypeProperty>

<owl:DatatypeProperty rdf:about="http://www.w3.org/ns/wsdl/http#faultSerialization">
  <rdfs:comment>
    declares the media type of the fault messages of an operation
  </rdfs:comment>
  <rdfs:range  rdf:resource="http://www.w3.org/2001/XMLSchema#string"/>
</owl:DatatypeProperty>

<owl:DatatypeProperty rdf:about="http://www.w3.org/ns/wsdl/http#defaultQueryParameterSeparator">
  <rdfs:comment>
    declares the default character to be used as query parameter separator by this binding's operations
  </rdfs:comment>
  <rdfs:range  rdf:resource="http://www.w3.org/2001/XMLSchema#string"/>
</owl:DatatypeProperty>

<owl:DatatypeProperty rdf:about="http://www.w3.org/ns/wsdl/http#queryParameterSeparator">
  <rdfs:comment>
    declares the character to be used as query parameter separator by an operation
  </rdfs:comment>
  <rdfs:range  rdf:resource="http://www.w3.org/2001/XMLSchema#string"/>
</owl:DatatypeProperty>

<owl:DatatypeProperty rdf:about="http://www.w3.org/ns/wsdl/http#headerName">
  <rdfs:range  rdf:resource="http://www.w3.org/2001/XMLSchema#string"/>
</owl:DatatypeProperty>

<owl:ObjectProperty rdf:about="http://www.w3.org/ns/wsdl/http#requiresHeader">
  <rdfs:range  rdf:resource="http://www.w3.org/ns/wsdl/http#HTTPHeader"/>
</owl:ObjectProperty>

<owl:ObjectProperty rdf:about="http://www.w3.org/ns/wsdl/http#offersHeader">
  <rdfs:range  rdf:resource="http://www.w3.org/ns/wsdl/http#HTTPHeader"/>
</owl:ObjectProperty>

<owl:Class rdf:about="http://www.w3.org/ns/wsdl/http#HTTPHeader">
  <rdfs:comment>
    an HTTP header
  </rdfs:comment>
  <rdfs:subClassOf>
    <owl:Restriction>
      <owl:onProperty rdf:resource="#typeDefinition"/>
      <owl:cardinality rdf:datatype="http://www.w3.org/2001/XMLSchema#nonNegativeInteger">1</owl:cardinality>
    </owl:Restriction>
  </rdfs:subClassOf>
  <rdfs:subClassOf>
    <owl:Restriction>
      <owl:onProperty rdf:resource="http://www.w3.org/ns/wsdl/http#headerName"/>
      <owl:cardinality rdf:datatype="http://www.w3.org/2001/XMLSchema#nonNegativeInteger">1</owl:cardinality>
    </owl:Restriction>
  </rdfs:subClassOf>
</owl:Class>

<owl:DatatypeProperty rdf:about="http://www.w3.org/ns/wsdl/http#errorCode">
  <rdfs:comment>
    declares the error status code that a fault will return
  </rdfs:comment>
  <rdfs:range  rdf:resource="http://www.w3.org/2001/XMLSchema#int"/>
</owl:DatatypeProperty>

<owl:DatatypeProperty
rdf:about="http://www.w3.org/ns/wsdl/http#defaultContentEncoding">
  <rdfs:comment>
    declares the default content encoding to be used by this binding's operation messages
  </rdfs:comment>
  <rdfs:range  rdf:resource="http://www.w3.org/2001/XMLSchema#string"/>
</owl:DatatypeProperty>

<owl:DatatypeProperty rdf:about="http://www.w3.org/ns/wsdl/http#contentEncoding">
  <rdfs:comment>
    declares the content encoding to be used by operation messages
  </rdfs:comment>
  <rdfs:range  rdf:resource="http://www.w3.org/2001/XMLSchema#string"/>
</owl:DatatypeProperty>

<owl:Class rdf:about="http://www.w3.org/ns/wsdl/http#BindingUsingHTTPCookies">
  <rdfs:comment>WSDL 2 binding that uses HTTP cookies</rdfs:comment>
</owl:Class>

<owl:DatatypeProperty rdf:about="http://www.w3.org/ns/wsdl/http#authenticationScheme">
  <rdfs:comment>
    declares the authentication scheme used by an endpoint, by default "none"
  </rdfs:comment>
  <rdfs:range  rdf:resource="http://www.w3.org/2001/XMLSchema#string"/>
</owl:DatatypeProperty>

<owl:DatatypeProperty rdf:about="http://www.w3.org/ns/wsdl/http#authenticationRealm">
  <rdfs:comment>
    declares the authentication realm used by an endpoint
  </rdfs:comment>
  <rdfs:range  rdf:resource="http://www.w3.org/2001/XMLSchema#string"/>
</owl:DatatypeProperty>


</rdf:RDF>

Appendix B: List of URIs used by the WSDL RDF mapping (Non-Normative)

This appendix lists all the URIs that are used by this WSDL RDF mapping, summarizing the new ones and the new statements about pre-existing ones.

The URI of the ontology for the WSDL RDF mapping, and also the container for all RDF classes and properties related to the core WSDL components, listed farther below.

http://www.w3.org/ns/wsdl-rdf

The RDF classes and properties mapping from the core WSDL components and their properties.

http://www.w3.org/ns/wsdl-rdf#Binding
http://www.w3.org/ns/wsdl-rdf#BindingFault
http://www.w3.org/ns/wsdl-rdf#BindingFaultReference
http://www.w3.org/ns/wsdl-rdf#BindingMessageReference
http://www.w3.org/ns/wsdl-rdf#BindingOperation
http://www.w3.org/ns/wsdl-rdf#Description
http://www.w3.org/ns/wsdl-rdf#Endpoint
http://www.w3.org/ns/wsdl-rdf#Interface
http://www.w3.org/ns/wsdl-rdf#InterfaceFault
http://www.w3.org/ns/wsdl-rdf#InterfaceFaultReference
http://www.w3.org/ns/wsdl-rdf#InterfaceMessageReference
http://www.w3.org/ns/wsdl-rdf#InterfaceOperation
http://www.w3.org/ns/wsdl-rdf#Service
http://www.w3.org/ns/wsdl-rdf#address
http://www.w3.org/ns/wsdl-rdf#binding
http://www.w3.org/ns/wsdl-rdf#bindingFault
http://www.w3.org/ns/wsdl-rdf#bindingFaultReference
http://www.w3.org/ns/wsdl-rdf#bindingMessageReference
http://www.w3.org/ns/wsdl-rdf#bindingOperation
http://www.w3.org/ns/wsdl-rdf#binds
http://www.w3.org/ns/wsdl-rdf#elementDeclaration
http://www.w3.org/ns/wsdl-rdf#endpoint
http://www.w3.org/ns/wsdl-rdf#extends
http://www.w3.org/ns/wsdl-rdf#implements
http://www.w3.org/ns/wsdl-rdf#interface
http://www.w3.org/ns/wsdl-rdf#interfaceFault
http://www.w3.org/ns/wsdl-rdf#interfaceFaultReference
http://www.w3.org/ns/wsdl-rdf#interfaceMessageReference
http://www.w3.org/ns/wsdl-rdf#interfaceOperation
http://www.w3.org/ns/wsdl-rdf#messageContentModel
http://www.w3.org/ns/wsdl-rdf#messageExchangePattern
http://www.w3.org/ns/wsdl-rdf#messageLabel
http://www.w3.org/ns/wsdl-rdf#operationStyle
http://www.w3.org/ns/wsdl-rdf#service
http://www.w3.org/ns/wsdl-rdf#typeDefinition
http://www.w3.org/ns/wsdl-rdf#usesBinding

A class and two properties for mapping of QName references (used for pointing to element declarations and type definitions).

http://www.w3.org/ns/wsdl-rdf#QName
http://www.w3.org/ns/wsdl-rdf#localName
http://www.w3.org/ns/wsdl-rdf#namespace

Classes indicating message direction of message references and fault references.

http://www.w3.org/ns/wsdl-rdf#InputMessage
http://www.w3.org/ns/wsdl-rdf#OutputMessage

A class of WSDL 2.0 operation styles.

http://www.w3.org/ns/wsdl-rdf#OperationStyle

Classes used in the RDF mapping of WSDL message exchange patterns.

http://www.w3.org/ns/wsdl-rdf#MessageExchangePattern
http://www.w3.org/ns/wsdl-rdf#definesMessageLabel
http://www.w3.org/ns/wsdl-rdf#MessageLabel
http://www.w3.org/ns/wsdl-rdf#NoFaults
http://www.w3.org/ns/wsdl-rdf#MessageTriggersFault
http://www.w3.org/ns/wsdl-rdf#FaultReplacesMessage

Classes used in the RDF mapping of message content models.

http://www.w3.org/ns/wsdl-rdf#MessageContentModel
http://www.w3.org/ns/wsdl-rdf#AnyContent
http://www.w3.org/ns/wsdl-rdf#ElementContent
http://www.w3.org/ns/wsdl-rdf#NoContent
http://www.w3.org/ns/wsdl-rdf#OtherContent

URIs of predefined WSDL 2.0 message exchange patters, the WSDL RDF mapping puts them into the appropriate classes of MEPs, and links them to their message labels, also listed.

http://www.w3.org/ns/wsdl/in-only
http://www.w3.org/ns/wsdl/in-only#In
http://www.w3.org/ns/wsdl/in-opt-out
http://www.w3.org/ns/wsdl/in-opt-out#In
http://www.w3.org/ns/wsdl/in-opt-out#Out
http://www.w3.org/ns/wsdl/in-out
http://www.w3.org/ns/wsdl/in-out#In
http://www.w3.org/ns/wsdl/in-out#Out
http://www.w3.org/ns/wsdl/out-in
http://www.w3.org/ns/wsdl/out-in#In
http://www.w3.org/ns/wsdl/out-in#Out
http://www.w3.org/ns/wsdl/out-only
http://www.w3.org/ns/wsdl/out-only#Out
http://www.w3.org/ns/wsdl/out-opt-in
http://www.w3.org/ns/wsdl/out-opt-in#In
http://www.w3.org/ns/wsdl/out-opt-in#Out
http://www.w3.org/ns/wsdl/robust-in-only
http://www.w3.org/ns/wsdl/robust-in-only#In
http://www.w3.org/ns/wsdl/robust-out-only
http://www.w3.org/ns/wsdl/robust-out-only#Out

Introduced in the WSDL RDF mapping as a class of safe interactions, used to capture the {safe} property on interface operations.

http://www.w3.org/ns/wsdl-extensions#SafeInteraction

URIs of the predefined WSDL 2.0 operation styles. The WSDL RDF mapping puts them into the class of operation styles.

http://www.w3.org/ns/wsdl/style/iri
http://www.w3.org/ns/wsdl/style/multipart
http://www.w3.org/ns/wsdl/style/rpc

URIs of classes and properties related to the RPC operation style, introduced in this WSDL RDF mapping.

http://www.w3.org/ns/wsdl/rpc#Argument
http://www.w3.org/ns/wsdl/rpc#InArgument
http://www.w3.org/ns/wsdl/rpc#InOutArgument
http://www.w3.org/ns/wsdl/rpc#OutArgument
http://www.w3.org/ns/wsdl/rpc#ReturnArgument
http://www.w3.org/ns/wsdl/rpc#Signature
http://www.w3.org/ns/wsdl/rpc#signature

The URI identifying WSDL 2.0 HTTP binding. The RDF mapping states that it is a subclass of WSDL Bindings, and also uses it as the container for the RDF mapping of components and properties related to the HTTP binding.

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

The URIs used in the RDF mapping of components and properties related to the HTTP binding.

http://www.w3.org/ns/wsdl/http#BindingUsingHTTPCookies
http://www.w3.org/ns/wsdl/http#HTTPHeader
http://www.w3.org/ns/wsdl/http#authenticationRealm
http://www.w3.org/ns/wsdl/http#authenticationScheme
http://www.w3.org/ns/wsdl/http#contentEncoding
http://www.w3.org/ns/wsdl/http#defaultContentEncoding
http://www.w3.org/ns/wsdl/http#defaultMethod
http://www.w3.org/ns/wsdl/http#defaultQueryParameterSeparator
http://www.w3.org/ns/wsdl/http#errorCode
http://www.w3.org/ns/wsdl/http#faultSerialization
http://www.w3.org/ns/wsdl/http#headerName
http://www.w3.org/ns/wsdl/http#inputSerialization
http://www.w3.org/ns/wsdl/http#location
http://www.w3.org/ns/wsdl/http#locationIgnoreUncited
http://www.w3.org/ns/wsdl/http#method
http://www.w3.org/ns/wsdl/http#offersHeader
http://www.w3.org/ns/wsdl/http#outputSerialization
http://www.w3.org/ns/wsdl/http#queryParameterSeparator
http://www.w3.org/ns/wsdl/http#requiresHeader

The URI identifying WSDL 2.0 SOAP binding. The RDF mapping states that it is a subclass of WSDL Bindings, and also uses it as the container for the RDF mapping of components and properties related to the SOAP binding.

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

The URIs used in the RDF mapping of components and properties related to the SOAP binding.

http://www.w3.org/ns/wsdl/soap#MustUnderstandSOAPHeaderBlock
http://www.w3.org/ns/wsdl/soap#SOAPHeaderBlock
http://www.w3.org/ns/wsdl/soap#action
http://www.w3.org/ns/wsdl/soap#defaultSoapMEP
http://www.w3.org/ns/wsdl/soap#faultCode
http://www.w3.org/ns/wsdl/soap#faultSubcodes
http://www.w3.org/ns/wsdl/soap#offersHeader
http://www.w3.org/ns/wsdl/soap#offersSOAPModule
http://www.w3.org/ns/wsdl/soap#protocol
http://www.w3.org/ns/wsdl/soap#requiresHeader
http://www.w3.org/ns/wsdl/soap#requiresSOAPModule
http://www.w3.org/ns/wsdl/soap#soapMEP
http://www.w3.org/ns/wsdl/soap#version

URIs from SOAP 1.2, the WSDL RDF mapping states that the two MEPs belong to the class.

http://www.w3.org/2006/02/soap12/abstractions#classOfMEPs
http://www.w3.org/2003/05/soap/mep/request-response/
http://www.w3.org/2003/05/soap/mep/soap-response/

URIs reused from RDF, RDF Schema and XML Schema; no new statements about them.

http://www.w3.org/1999/02/22-rdf-syntax-ns#Seq
http://www.w3.org/1999/02/22-rdf-syntax-ns#type
http://www.w3.org/2000/01/rdf-schema#label
http://www.w3.org/2001/XMLSchema#boolean
http://www.w3.org/2001/XMLSchema#int

Reused from SAWSDL, no new statements.

http://www.w3.org/ns/sawsdl#modelReference

Appendix C. Acknowledgements (Non-Normative)

This document is the work of the W3C Web Service Description Working Group.

Members of the Working Group are (at the time of writing, and by alphabetical order): Charlton Barreto (Adobe Systems, Inc), Allen Brookes (Rogue Wave Softwave), Dave Chappell (Sonic Software), Helen Chen (Agfa-Gevaert N. V.), Roberto Chinnici (Sun Microsystems), Kendall Clark (University of Maryland), Glen Daniels (Sonic Software), Paul Downey (British Telecommunications), Youenn Fablet (Canon), Ram Jeyaraman (Microsoft), Tom Jordahl (Adobe Systems), Anish Karmarkar (Oracle Corporation), Jacek Kopecky (DERI Innsbruck at the Leopold-Franzens-Universität Innsbruck, Austria), Amelia Lewis (TIBCO Software, Inc.), Philippe Le Hegaret (W3C), Michael Liddy (Education.au Ltd.), Kevin Canyang Liu (SAP AG), Jonathan Marsh (WSO2), Monica Martin (Sun Microsystems), Josephine Micallef (SAIC - Telcordia Technologies), Jeff Mischkinsky (Oracle Corporation), Dale Moberg (Cyclone Commerce), Jean-Jacques Moreau (Canon), David Orchard (BEA Systems, Inc.), Gilbert Pilz (BEA Systems, Inc.), Tony Rogers (Computer Associates), Arthur Ryman (IBM), Adi Sakala (IONA Technologies), Michael Shepherd (Xerox), Asir Vedamuthu (Microsoft Corporation), Sanjiva Weerawarana (WSO2), Ümit Yalçınalp (SAP AG), Peter Zehler (Xerox).

Previous members were: Eran Chinthaka (WSO2), Mark Nottingham (BEA Systems, Inc.), Hugo Haas (W3C), Vivek Pandey (Sun Microsystems), Bijan Parsia (University of Maryland), Lily Liu (webMethods, Inc.), Don Wright (Lexmark), Joyce Yang (Oracle Corporation), Daniel Schutzer (Citigroup), Dave Solo (Citigroup), Stefano Pogliani (Sun Microsystems), William Stumbo (Xerox), Stephen White (SeeBeyond), Barbara Zengler (DaimlerChrysler Research and Technology), Tim Finin (University of Maryland), Laurent De Teneuille (L'Echangeur), Johan Pauhlsson (L'Echangeur), Mark Jones (AT&T), Steve Lind (AT&T), Sandra Swearingen (U.S. Department of Defense, U.S. Air Force), Philippe Le Hégaret (W3C), Jim Hendler (University of Maryland), Dietmar Gaertner (Software AG), Michael Champion (Software AG), Don Mullen (TIBCO Software, Inc.), Steve Graham (Global Grid Forum), Steve Tuecke (Global Grid Forum), Michael Mahan (Nokia), Bryan Thompson (Hicks & Associates), Ingo Melzer (DaimlerChrysler Research and Technology), Sandeep Kumar (Cisco Systems), Alan Davies (SeeBeyond), Jacek Kopecky (Systinet), Mike Ballantyne (Electronic Data Systems), Mike Davoren (W. W. Grainger), Dan Kulp (IONA Technologies), Mike McHugh (W. W. Grainger), Michael Mealling (Verisign), Waqar Sadiq (Electronic Data Systems), Yaron Goland (BEA Systems, Inc.), Ümit Yalçınalp (Oracle Corporation), Peter Madziak (Agfa-Gevaert N. V.), Jeffrey Schlimmer (Microsoft Corporation), Hao He (The Thomson Corporation), Erik Ackerman (Lexmark), Jerry Thrasher (Lexmark), Prasad Yendluri (webMethods, Inc.), William Vambenepe (Hewlett-Packard Company), David Booth (W3C), Sanjiva Weerawarana (IBM), Asir Vedamuthu (webMethods, Inc.), Igor Sedukhin (Computer Associates), Martin Gudgin (Microsoft Corporation), Rebecca Bergersen (IONA Technologies), Ugo Corda (SeeBeyond).

The people who have contributed to discussions on www-ws-desc@w3.org are also gratefully acknowledged.