2.1.1 The Description Component
At the abstract level, the Description component is just a
container for two categories of components: WSDL 2.0 components and
type system components.
WSDL 2.0 components are interfaces, bindings and services. Type
system components are element declarations and type
definitions.
deleted text: Interface, Binding, Service, Element Declaration, and
Type Definition components are directly contained in the
Description component and are referred to as <em> top-level
components </em>. The top-level WSDL 2.0 components contain
other components, e.g. Interface Operation and Endpoint, which are
referred to as <em> nested components </em>. Nested
components may contain other nested components. The component that
contains a nested component is referred to as the <em> parent
</em> of the nested components. Nested components have a
{parent} property that is a reference to their parent component.
</p> <a name="zed-Parent" id="zed-Parent"> </a>
<a name="zed-ParentRI" id="zed-ParentRI"> </a>
<p> Type system components describe the constraints on
a message's content. By default, these constraints are expressed in
terms of the [ XML Information
Set ], i.e. they define the [local name], [namespace
name], [children] and [attributes] properties of an element
information item. item . Type systems based upon other data
models are generally accommodated by extensions to WSDL 2.0; see
<a
href="#language-extensibility"> 6. Language Extensibility . In
the case where they define information equivalent to that of a XML
Schema global element declaration, they can be treated as if they
were such a declaration.
This specification does not define the behavior of a WSDL 2.0
document that uses multiple schema languages for describing type
system components simultaneously.
An Element
Declaration component defines the
name and content model of an element information item such as that defined by an XML Schema global element
declaration. It has a { name } property that
is the QName of the element
information item .
A Type
Definition component defines the
content model of an element
information item such as that
defined by an XML Schema global type definition. It has a {
name } property that
is the QName of the type.
Interface ,Binding
,Service ,Element
Declaration ,and Type
Definition components are
directly contained in the Description component
and are referred to as top-level
components .The top-level WSDL
2.0 components contain other components, e.g. Interface
Operation and Endpoint
,which are referred to as
nested components
.Nested components may contain other nested
components. The component that contains a nested component is
referred to as the parent of the nested
components. Nested components have a { parent } property that
is a reference to their parent component.
The properties of the Description component are as
follows:
<a name= "zed-DescriptionRI"
id="zed-DescriptionRI">
The set of top-level components contained in the Description component associated with
an initial WSDL 2.0 document consists of the components defined in
the initial document and the components associated with the
documents that the initial document includes or imports. The
component model makes no distinction between the components that
are defined in the initial document versus those that are defined
in the included or imported documents. However, any WSDL 2.0
document that contains component definitions that refer by QName to
WSDL 2.0 components that belong to a different namespace MUST
contain a ws:import element information item
for that namespace (see <a href=
"#imports"> 4.2 Importing
Descriptions ). Furthermore, all QName references, whether
to the same or to different namespaces MUST resolve to components
(see 2.19 QName resolution ).
deleted text: <a name="zed-DescriptionKeys"
id="zed-DescriptionKeys"> </a>
In addition to WSDL 2.0 components and type system components,
additional extension components MAY be added via extensibility
6. Language
Extensibility . Further, additional properties to WSDL 2.0
and type system components MAY also be added via extensibility.
2.1.2
XML Representation of Description Component
<description
targetNamespace="xs:anyURI" >
<documentation />?
<documentation />*
[ <import /> | <include /> ]*
<types />?
[ <interface /> | <binding /> | <service /> ]*
</description>
WSDL 2.0 definitions are represented in XML by one or more WSDL
2.0 Information Sets (Infosets), that is one or more
description element information item s. A
WSDL 2.0 Infoset contains representations for a collection of WSDL
2.0 components which share a common target namespace. A WSDL 2.0
Infoset which contains one or more import element
information item s 4.2 Importing
Descriptions corresponds to a collection with components
drawn from multiple target namespaces.
The components directly defined or included within a Description component are said to
belong to the same target namespace . The target namespace
therefore groups a set of related component definitions and
represents an unambiguous name for the intended semantics of the
collection of components. The value of the
targetNamespace attribute information item
SHOULD be a dereferenceable URI.
IRI (see [ IETF RFC 3987
]). It SHOULD resolve to a human or
machine processable document that directly or indirectly defines
the intended semantics of those components. It MAY resolve to a
WSDL 2.0 document which provides service description information
for that namespace.
If a service description is split into multiple documents (which
may be combined as needed via 4.1 Including
Descriptions ), then the targetNamespace
attribute information item SHOULD resolve to a master
document which includes all the WSDL 2.0 documents needed for that
service description. This approach enables the WSDL 2.0 component
designators' fragment identifiers to be properly resolvable.
Imported components have different target namespace values from
the Description component that
is importing them. Thus importing is the mechanism to use
components from one namespace in another set of definitions.
Each WSDL 2.0 or type system component MUST be uniquely
identified by its qualified name. That is, if two distinct
components of the same kind (Interface, (
Interface ,Binding , etc.) are in the same target
namespace, then their QNames MUST be unique. However, different
kinds of components (e.g., an Interface component and a Binding component) MAY have the same
QName. Thus, QNames of components must be unique within the space
of those components in a given target namespace.
The description element information item
has the following Infoset properties:
-
A [local name] of description .
-
A [namespace name] of "http://www.w3.org/2005/05/wsdl". "http://www.w3.org/2005/08/wsdl".
-
One or more attribute information item s amongst its
[attributes] as follows:
-
A REQUIRED targetNamespace attribute
information item as described below in 2.1.2.1 targetNamespace
attribute information item .
-
Zero or more namespace qualified attribute information
item s whose [namespace name] is NOT "http://www.w3.org/2005/05/wsdl". "http://www.w3.org/2005/08/wsdl".
-
Zero or more element information item s amongst its
[children], in order as follows:
-
An OPTIONAL Zero or more documentation
element information item s
(see 5. Documentation
).
-
Zero or more element information item s from among the
following, in any order:
-
Zero or more include element information
item s (see 4.1 Including
Descriptions )
-
Zero or more import element information
item s (see 4.2 Importing
Descriptions )
-
Zero or more namespace-qualified element information
item s whose [namespace name] is NOT "http://www.w3.org/2005/05/wsdl". "http://www.w3.org/2005/08/wsdl".
-
An OPTIONAL types element information item
(see 3. Types ).
-
Zero or more element information item s from among the
following, in any order:
2.1.2.1
targetNamespace attribute information
item
The targetNamespace attribute information
item defines the namespace affiliation of top-level components
defined in this description element information
item . Interfaces, Bindings
Interface ,Binding and
Services Service are
top-level components.
The targetNamespace attribute information
item has the following Infoset properties:
The type of the targetNamespace attribute
information item is xs:anyURI . The Its value
deleted text: of the <code> targetNamespace </code>
<em> attribute information item </em> MUST be an
absolute URI IRI (see [ <a
href="#RFC3986"> IETF RFC 3986 3987 ]).