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

1.4.1 RFC 2119 Keywords

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

1.4.2 RFC 3986 Namespaces

Namespace names of the general form:

• "http://example.org/..." and

• "http://example.com/..."

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

1.4.3 XML Schema anyURI

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

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

1.4.4 Prefixes and Namespaces Used in This Specification

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

1.4.5 Terms Used in This Specification

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

Actual Value

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

Inlined Schema

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

1.4.6 XML Information Set Properties

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

1.4.7 WSDL 2.0 Component Model Properties

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

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

1.4.8 Z Notation

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

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

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

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

1.4.9 BNF Pseudo-Schemas

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

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

1.4.10 Assertions

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

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

2.1.1 The Description Component

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

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

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

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

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

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

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

The properties of the Description component are as follows:

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

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

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

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

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

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

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

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

2.1.2 XML Representation of Description Component

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

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

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

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

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

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

The description element information item has the following Infoset properties:

• A [local name] of description.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

2.1.3 Mapping Description's XML Representation to Component Properties

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

2.2.1 The Interface Component

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

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

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

The properties of the Interface component are as follows:

• {name} REQUIRED. An xs:QName.

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

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

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

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

2.2.2 XML Representation of Interface Component

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

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

• A [local name] of interface

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

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

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

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

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

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

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

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

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

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

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

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

2.2.3 Mapping Interface's XML Representation to Component Properties

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

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

2.3.1 The Interface Fault Component

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

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

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

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

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

The properties of the Interface Fault component are as follows:

• {name} REQUIRED. An xs:QName.

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

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

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

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

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

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

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

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

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

2.3.2 XML Representation of Interface Fault Component

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

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

• A [local name] of fault

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

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

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

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

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

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

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

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

2.3.3 Mapping Interface Fault's XML Representation to Component Properties

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

2.4.1 The Interface Operation Component

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

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

The properties of the Interface Operation component are as follows:

• {name} REQUIRED. An xs:QName.

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

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

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

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

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

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

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

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

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

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

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

2.4.2 XML Representation of Interface Operation Component

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

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

• A [local name] of operation

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

2.4.3 Mapping Interface Operation's XML Representation to Component Properties

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

2.5.1 The Interface Message Reference Component

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

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

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

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

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

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

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

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

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

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

2.5.2 XML Representation of Interface Message Reference Component

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

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

• A [local name] of input or output

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

2.6.1 The Interface Fault Reference Component

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

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

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

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

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

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

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

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

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

2.6.2 XML Representation of Interface Fault Reference

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

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

• A [local name] of infault or outfault

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

2.7.1 The Binding Component

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

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

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

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

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

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

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

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

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

The properties of the Binding component are as follows:

• {name} REQUIRED. An xs:QName.

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

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

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

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

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

2.7.2 XML Representation of Binding Component

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

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

• A [local name] of binding

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

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

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

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

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

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

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

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

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

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

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

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

2.7.3 Mapping Binding's XML Representation to Component Properties

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

2.8.1 The Binding Fault Component

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

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

The properties of the Binding Fault component are as follows:

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

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

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

2.8.2 XML Representation of Binding Fault Component

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

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

• A [local name] of fault

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

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

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

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

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

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

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

2.8.3 Mapping Binding Fault's XML Representation to Component Properties

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

2.9.1 The Binding Operation Component

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

The properties of the Binding Operation component are as follows:

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

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

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

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

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

2.9.2 XML Representation of Binding Operation Component

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

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

• A [local name] of operation

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

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

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

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

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

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

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

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

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

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

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

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

2.9.3 Mapping Binding Operation's XML Representation to Component Properties

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

2.10.1 The Binding Message Reference Component

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

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

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

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

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

2.10.2 XML Representation of Binding Message Reference Component

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

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

• A [local name] of input or output.

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

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

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

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

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

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

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

2.10.3 Mapping Binding Message Reference's XML Representation to Component Properties

The mapping from the XML Representation of the binding element information item (see 2.10.2 XML Representation of Binding Message Reference Component) to the properties of the Binding Message Reference component is as described in Table 2-10 and uses the definitions below.

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

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

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

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

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

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

2.11.1 The Binding Fault Reference Component

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

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

• {interface fault reference} REQUIRED. An Interface Fault Reference component among those in the {interface fault references} property of the Interface Operation component being bound by the parent Binding Operation component.

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

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

2.11.2 XML Representation of Binding Fault Reference Component

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

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

• A [local name] of infault or outfault.

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

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

  • A REQUIRED ref attribute information item as described below in 2.11.2.1 ref attribute information item with infault or outfault [owner element].

    An OPTIONAL messageLabel attribute information item as described below in 2.11.2.2 messageLabel attribute information item with infault or outfault [owner element].

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

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

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

  2. Zero or more namespace-qualified element information items whose [namespace name] is NOT "http://www.w3.org/ns/wsdl". Such element information items are considered to be binding fault reference extension elements as described below (see 2.11.2.3 Binding Fault Reference extension elements).

2.11.3 Mapping Binding Fault Reference's XML Representation to Component Properties

The mapping from the XML Representation of the binding element information item (see 2.11.2 XML Representation of Binding Fault Reference Component) to the properties of the Binding Fault Reference component is as described in Table 2-11 and uses the definitions below.

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

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

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

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

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

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

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

There MUST be an Interface Fault Reference component in the {interface fault references} of the Interface Operation being bound with {message label} equal to the effective message label and with {interface fault} equal to an Interface Fault component with {name} equal to the actual value of the ref attribute information item.^†

2.12.1 The Service Component

A Service component describes a set of endpoints (see 2.13 Endpoint) at which a particular deployed implementation of the service is provided. The endpoints thus are in effect alternate places at which the service is provided.

Services are named constructs and can be referred to by QName (see 2.17 QName resolution).

The properties of the Service component are as follows:

• {name} REQUIRED. An xs:QName.

• {interface} REQUIRED. An Interface component.

• {endpoints} REQUIRED. A non-empty set of Endpoint components.

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

2.12.2 XML Representation of Service Component

<description>
  <service
        name="xs:NCName" 
        interface="xs:QName" >
    <documentation />*
    <endpoint />+
  </service>
</description>

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

• A [local name] of service

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

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

  • A REQUIRED name attribute information item as described below in 2.12.2.1 name attribute information item with service [owner element].

  • A REQUIRED interface attribute information item as described below in 2.12.2.2 interface attribute information item with service [owner element].

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

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

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

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

     • One or more endpoint element information items (see 2.13.2 XML Representation of Endpoint Component

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

2.12.3 Mapping Service's XML Representation to Component Properties

The mapping from the XML Representation of the service element information item (see 2.12.2 XML Representation of Service Component) to the properties of the Service component is as described in Table 2-12.

2.13.1 The Endpoint Component

An Endpoint component defines the particulars of a specific endpoint at which a given service is available.

Endpoint components are local to a given Service component (see A.2 Fragment Identifiers).

The Binding component specified by the {binding} property of an Endpoint component is said to be applied to the Interface component which is the value of the {interface} property of the parent Service component of the Endpoint. According to the constraints given below, if this Binding component has an {interface} property, its value must be the Interface component the Binding component is applied to.

The {address} property is optional to allow for means other than IRIs to be used, e.g. a WS-Addressing Endpoint Reference [WSA 1.0 Core]. It is also possible that, in certain scenarios, an address will not be required, in which case this property may be absent.

The properties of the Endpoint component are as follows:

• {name} REQUIRED. An xs:NCName.

• {binding} REQUIRED. A Binding component.

• {address} OPTIONAL. An xs:anyURI. This xs:anyURI MUST be an absolute IRI as defined by [IETF RFC 3987].^† If present, the value of this attribute represents the network address at which the service indicated by the parent Service component's {interface} property is offered via the binding referred to by the {binding} property. Note that the presence in this property of the characters "?" and "#" can conflict with those potentially added by the query string serialization mechanism, as defined in Serialization as "application/x-www-form-urlencoded" ([WSDL 2.0 Adjuncts], section 6.8.2).

• {parent} REQUIRED. The Service component that contains this component in its {endpoints} property.

For each Endpoint component in the {endpoints} property of a Service component, the {name} property MUST be unique. Note that this constraint is enforced by the normative WSDL 2.0 XML schema.

For each Endpoint component in the {endpoints} property of a Service component, the {binding} property MUST either be a Binding component with an unspecified {interface} property or a Binding component with an {interface} property equal to the {interface} property of the Service component.^†

2.13.2 XML Representation of Endpoint Component

<description>
  <service>
    <endpoint
          name="xs:NCName" 
          binding="xs:QName"
          address="xs:anyURI"? >
      <documentation />*
    </endpoint>+
  </service>
</description>

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

• A [local name] of endpoint.

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

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

  • A REQUIRED name attribute information item as described below in 2.13.2.1 name attribute information item with endpoint [owner element].

  • A REQUIRED binding attribute information item as described below in 2.13.2.2 binding attribute information item with endpoint [owner element].

  • An OPTIONAL address attribute information item as described below in 2.13.2.3 address attribute information item with endpoint [owner element].

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

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

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

  2. Zero or more namespace-qualified element information items whose [namespace name] is NOT "http://www.w3.org/ns/wsdl". Such element information items are considered to be endpoint extension elements as described below (see 2.13.2.4 Endpoint extension elements).

2.13.3 Mapping Endpoint's XML Representation to Component Properties

The mapping from the XML Representation of the endpoint element information item (see 2.13.2 XML Representation of Endpoint Component) to the properties of the Endpoint component is as described in Table 2-13.

3.1.1 Importing XML Schema

Importing an XML Schema uses the syntax and semantics of the xs:import mechanism defined by XML Schema [XML Schema: Structures], [XML Schema: Datatypes], with the differences defined in this section and the following one. The schema components defined in the imported namespace are referenceable by QName (see 2.17 QName resolution). Only components in the imported namespace are referenceable in the WSDL 2.0 document. For each component in the imported namespace, a corresponding Element Declaration component or Type Definition component MUST appear in the {element declarations} or {type definitions} property respectively of the Description component corresponding to the WSDL document that imports the schema, or that imports directly or indirectly a WSDL document that imports the schema.^† Schema components not in an imported namespace MUST NOT appear in the {element declarations} or {type definitions} properties.^†

A child element information item of the types element information item is defined with the Infoset properties as follows:

• A [local name] of "import".

• A [namespace name] of "http://www.w3.org/2001/XMLSchema".

• One or two attribute information items as follows:

  • A REQUIRED namespace attribute information item as described below.

  • An OPTIONAL schemaLocation attribute information item as described below.

3.1.2 Inlining XML Schema

Inlining an XML schema uses the existing top-level xs:schema element information item defined by XML Schema [XML Schema: Structures]. Conceptually, inlining can be viewed as simply cutting and pasting an existing schema document to a location inside the types element information item.

The schema components defined and declared in the inlined schema document are referenceable by QName (see 2.17 QName resolution). Only components defined and declared in the schema itself and components included by it via xs:include are referenceable. For each component defined and declared in the inlined schema document or included by xs:include, a corresponding Element Declaration component or Type Definition component MUST appear in the {element declarations} property or {type definitions} property respectively of the Description component corresponding to the WSDL document that contains the schema, or that imports directly or indirectly a WSDL document that contains the schema.^†Schema components not defined or declared in the inlined schema document or included by xs:include MUST NOT appear in the {element declarations} or {type definitions} properties.^†

Note that components in the namespace that the inline schema imports via xs:import are not automatically referenceable from the WSDL 2.0 document that contains the inline schema. If the namespace referenced in a QName is contained in an inline schema, it MAY be imported without a schemaLocation attribute, so long as the inline schema has been resolved in the current component model.

Note that components defined in an inlined XML schema are not automatically referenceable within the WSDL 2.0 document that imported (using wsdl:import) the WSDL 2.0 document that inlines the schema (see 4.2 Importing Descriptions for more details). For this reason, it is recommended that XML schema documents intended to be shared across several WSDL 2.0 documents be placed in separate XML schema documents and imported using xs:import, rather than inlined inside a WSDL 2.0 document.

Inside an inlined XML schema, the xs:import and xs:include element information items MAY be used to refer to other XML schemas inlined in the same or other WSDL 2.0 document, provided that an appropriate value, such as a fragment identifier (see [XML Schema: Structures] 4.3.1) is specified for their schemaLocation attribute information items. For xs:import, the schemaLocation attribute is not required so long as the namespace has been resolved in the current component model. The semantics of such element information items are governed solely by the XML Schema specification [XML Schema: Structures].

A WSDL 2.0 document MAY inline two or more schemas from the same targetNamespace. For example, two or more inlined schemas can have the same targetNamespace provided that they do not define the same elements or types. A WSDL 2.0 document MUST NOT define the same element or type in more than one inlined schema.^† Note that it is the responsibility of the underlying XML Schema processor to sort out a coherent set of schema components.

The xs:schema element information item has the following Infoset properties:

• A [local name] of schema.

• A [namespace name] of "http://www.w3.org/2001/XMLSchema".

• Additional OPTIONAL attribute information items as specified for the xs:schema element information item by the XML Schema specification.

• Zero or more child element information items as specified for the xs:schema element information item by the XML Schema specification.

3.1.3 References to Element Declarations and Type Definitions

Whether inlined or imported, the global element declarations present in a schema are referenceable from an Interface Message Reference or Interface Fault component. Similarly, regardless of whether they are inlined or imported, the global type definitions present in a schema are referenceable from other components.

A named, global xs:element declaration is referenceable from the element attribute information item of an input, output (see 2.5.2 XML Representation of Interface Message Reference Component) or fault element information item (see 2.3.2 XML Representation of Interface Fault Component). The QName of the element declaration is constructed from the targetNamespace of the schema and the value of the name attribute information item of the xs:element element information item. Note that the element attribute information item cannot refer to a global xs:simpleType or xs:complexType definition, since these are in a different symbol space than global element declarations. If the element attribute information item erroneously contains the QName of a type definition then this would result in a failure to resolve the element declaration.

3.3.1 wsdlx:interface attribute information item

WSDL 2.0 provides a global attribute information item with the following Infoset properties:

• A [local name] of interface.

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

The type of the wsdlx:interface attribute information item is an xs:QName that specifies the {name} property of an Interface component.^†

3.3.2 wsdlx:binding attribute information item

WSDL 2.0 provides a global attribute information item with the following Infoset properties:

• A [local name] of binding.

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

The type of the wsdlx:binding attribute information item is an xs:QName that specifies the {name} property of a Binding component.^†

3.3.3 wsdlx:interface and wsdlx:binding Consistency

The wsdlx:interface and wsdlx:binding attributes may be used either independently or together. If wsdlx:interface and wsdlx:binding are used together then they MUST satisfy the same consistency rules that apply to the {interface} property of a Service component and the {binding} property of a nested Endpoint component, that is either the binding refers the interface of the service or the binding refers to no interface.^†

3.3.4 Use of wsdlx:interface and wsdlx:binding with xs:anyURI

wsdlx:interface and wsdlx:binding are used to describe element information items and attribute information items whose type is xs:anyURI or a restriction of it, as well messages that contain the {address} property of an Endpoint. This is accomplished by including the wsdlx:interface and/or wsdlx:binding attribute information item in the xs:element, xs:simpleType, or xs:attribute element information item of the corresponding XML Schema component.

4.1.1 location attribute information item with include [owner element]

The location attribute information item has the following Infoset properties:

• A [local name] of location.

• A [namespace name] which has no value.

A location attribute information item is of type xs:anyURI. Its actual value is the location of some information about the namespace identified by the targetNamespace attribute information item of the containing description element information item.

The IRI indicated by location MUST resolve to a WSDL 2.0 document.^† (see 7. Locating WSDL 2.0 Documents)

The actual value of the targetNamespace attribute information item of the included WSDL 2.0 document MUST match the actual value of the targetNamespace attribute information item of the description element information item which is the [parent] of the include element information item.^†

4.2.1 namespace attribute information item

The namespace attribute information item has the following Infoset properties:

• A [local name] of namespace.

• A [namespace name] which has no value.

The namespace attribute information item is of type xs:anyURI. Its actual value indicates that the containing WSDL 2.0 document MAY contain qualified references to WSDL 2.0 components in that namespace (via one or more prefixes declared with namespace declarations in the normal way). This value MUST NOT match the actual value of targetNamespace attribute information item in the enclosing WSDL 2.0 document.^†  If the location attribute in the import element information item is dereferencable, then it MUST reference a WSDL 2.0 document.^† If the location attribute information item of the import element information item is dereferencable, then the actual value of the namespace attribute information item MUST be identical to the actual value of the targetNamespace attribute information item of the referenced WSDL 2.0 document (see 7. Locating WSDL 2.0 Documents).^†

4.2.2 location attribute information item with import [owner element]

The location attribute information item has the following Infoset properties:

• A [local name] of location.

• A [namespace name] which has no value.

The location attribute information item is of type xs:anyURI. Its actual value, if present, gives a hint as to where a serialization of a WSDL 2.0 document with definitions for the imported namespace can be found.

The location attribute information item is optional. This allows WSDL 2.0 components to be constructed from information other than an XML 1.0 serialization of a WSDL 2.0 document. It also allows the development of WSDL 2.0 processors that have a prior (i.e., built-in) knowledge of certain namespaces.

6.1.1 Mandatory extensions

Extension elements can be marked as mandatory by annotating them with a wsdl:required attribute information item (see 6.1.2 required attribute information item) with a value of "true". A mandatory extension is an extension that MAY change the meaning of the element to which it is attached, such that the meaning of that element is no longer governed by this specification. Instead, the meaning of an element containing a mandatory extension is governed by the meaning of that extension. Thus, the definition of the element's meaning is delegated to the specification that defines the extension.

An extension that is NOT marked as mandatory MUST NOT invalidate the meaning of any part of a WSDL 2.0 document.^† Thus, a NON-mandatory extension merely provides additional description of capabilities of the service. This specification does not provide a mechanism to mark extension attributes as being required. Therefore, all extension attributes are NON-mandatory.

If a WSDL 2.0 document declares an extension as optional (i.e., NON-mandatory), then the Web service MUST NOT assume that the client supports that extension unless the Web service knows (through some other means) that the client has in fact elected to engage and support that extension.^†

On the other hand, a client MAY engage an extension that is declared as optional in the WSDL 2.0 document. Therefore, the Web service MUST support every extension that is declared as optional in the WSDL 2.0 document, in addition to supporting every extension that is declared as mandatory.^†

Validity of a WSDL 2.0 document can only be assessed within the context of a set of supported extensions. A WSDL 2.0 document that contains a required but unsupported extension is invalid with respect to that set of supported extensions.

6.1.2 required attribute information item

WSDL 2.0 provides a global attribute information item with the following Infoset properties:

• A [local name] of required.

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

The type of the required attribute information item is xs:boolean. Its default value is "false" (hence extensions are NOT required by default).