Table of contents

Appendices

6.1 Element based extensibility

WSDL allows extensions to be defined in terms of element information items. Several abstract global element declarations serve as the heads of substitution groups. Some are specific to a particular point in the schema while others appear in multiple places. This allows extension to be specific to a particular point of the WSDL schema or more general. [tabelemsubgroup] shows the complete list of element substitution groups that along with their allowed locations.

It is expected that extensions will want to add to the existing properties of components in the component model. The specification for an extension element information item should include definitions of any such properties and the mapping between the XML representation of the extension and the properties in the component model.

The WSDL schema also defines a base type for use by extensibility elements. [Base type for extensibility elements] shows the type definition. The use of this type as a base type is optional. The element declarations which serve as the heads of the defined substitution groups are all of type xs:anyType.

Extensibility elements are commonly used to specify some technology specific binding. They allow innovation in the area of network and message protocols without having to revise the base WSDL specification. WSDL recommends that specifications defining such protocols also define any necessary WSDL extensions used to describe those protocols or formats.

An extension element is said to be processed if a WSDL processor decides (through whatever means) that its parent (an element information item in the http://www.w3.org/2003/03/wsdl namespace) will be processed. Note that it is possible for WSDL processors to process only a subset of a given WSDL document. For instance, a tool may wish to focus on portTypes and operations only, and will consequently skip bindings.

1List of element substitution group based extensibility pointstabelemsubgroup Element substitution groups defined for element based extensibility Element name Allowed in [children] property of Notes

11globalExt	11 wsdl:definitions after wsdl:import, wsdl:include and wsdl:types element information items if present. wsdl:message wsdl:part wsdl:portType wsdl:operation wsdl:input wsdl:output wsdl:fault wsdl:binding wsdl:service wsdl:port	11This element information item serves as the head of a substitution group for extensibility elements that wish to appear as a child of any element information item in the http://www.w3.org/2003/03/wsdl namespace with the exception of wsdl:import, wsdl:include and wsdl:types.
11msgAndportTypeExt	11 wsdl:message wsdl:portType	11 This element information item serves as the head of a substitution group for extensibility elements that wish to appear as a child of wsdl:message and/or wsdl:portType
11msgportTypeAndBindingExt	11 wsdl:message wsdl:portType wsdl:binding	11 This element information item serves as the head of a substitution group for extensibility elements that wish to appear as a child of wsdl:message, wsdl:portType and/or wsdl:binding
11msgportTypeBindingServiceExt	11 wsdl:message wsdl:portType wsdl:binding wsdl:service	11 This element information item serves as the head of a substitution group for extensibility elements that wish to appear as a child of wsdl:message, wsdl:portType, wsdl:binding and/or wsdl:service
11bindingAndServiceExt	11 wsdl:binding wsdl:service	11 This element information item serves as the head of a substitution group for extensibility elements that wish to appear as a child of wsdl:binding and/or wsdl:service
11preImportInclude	11 wsdl:definitions before wsdl:import and wsdl:include, if present.	11 This element information item serves as the head of a substitution group for extensibility elements that wish to appear before the wsdl:import and wsdl:include element information items
11inImportInclude	11 wsdl:definitions before, between or after wsdl:import and wsdl:include, if present.	11 This element information item serves as the head of a substitution group for extensibility elements that wish to appear interleaved with the wsdl:import and wsdl:include element information items
11preTypes	11 wsdl:definitions after wsdl:import and wsdl:include and before wsdl:types, if present.	11 This element information item serves as the head of a substitution group for extensibility elements that wish to appear after the wsdl:import and wsdl:include element information items but before the wsdl:types element information item
11postTypes	11 wsdl:definitions after wsdl:types, if present.	11 This element information item serves as the head of a substitution group for extensibility elements that wish to appear after the wsdl:types element information item ( potentially interleaved with wsdl:message, wsdl:portType, wsdl:/binding and wsdl:service element information items.
31Abstract elements related to message
11msgExt	11 wsdl:message	11 This element information item serves as the head of a substitution group for extensibility elements that wish to appear as children of wsdl:message
11msgPrePartExt	11 wsdl:message before wsdl:part element information items, if present.	11 This element information item serves as the head of a substitution group for extensibility elements that wish to appear as children of wsdl:message before wsdl:part
11msgPostPartExt	11 wsdl:message after wsdl:part element information items, if present.	11 This element information item serves as the head of a substitution group for extensibility elements that wish to appear as children of wsdl:message after wsdl:part
11msgPartExt	11 wsdl:part	11 This element information item serves as the head of a substitution group for extensibility elements that wish to appear as children of wsdl:message/wsdl:part
31Abstract elements related to portType
11portTypeExt	11 wsdl:portType	11 This element information item serves as the head of a substitution group for extensibility elements that wish to appear as children of wsdl:portType
11portTypePreOpExt	11 wsdl:portType before wsdl:operation element information items, if present.	11This element information item serves as the head of a substitution group for extensibility elements that wish to appear as children of wsdl:portType before wsdl:operation
11portTypePostOpExt	11 wsdl:portType after wsdl:operation element information items, if present.	11 This element information item serves as the head of a substitution group for extensibility elements that wish to appear as children of wsdl:portType after wsdl:operation
11portTypeOpExt	11 wsdl:operation with wsdl:portType [parent]	11 This element information item serves as the head of a substitution group for extensibility elements that wish to appear as children of wsdl:operation when it is a child of wsdl:portType
11portTypeOpMsgExt	11 wsdl:input with wsdl:operation [parent] which itself has wsdl:portType [parent] wsdl:output with wsdl:operation [parent] which itself has wsdl:portType [parent]	11 This element information item serves as the head of a substitution group for extensibility elements that wish to appear as children of wsdl:input or wsdl:output when they appear as children of wsdl:operation which itself appears as a child of wsdl:portType
11portTypeOpFaultExt	11 wsdl:fault with wsdl:operation [parent] which itself has wsdl:portType [parent]	11 This element information item serves as the head of a substitution group for extensibility elements that wish to appear as children of wsdl:fault when it appears as a child of wsdl:operation which itself appears as a child of wsdl:portType
31Abstract elements related to bindings
11bindingExt	11 wsdl:binding	11 This element information item serves as the head of a substitution group for extensibility elements that wish to appear as children of wsdl:binding
11bindingPreOpExt	11 wsdl:binding before wsdl:operation element information items, if present.	11 This element information item serves as the head of a substitution group for extensibility elements that wish to appear as children of wsdl:binding before wsdl:operation
11bindingPostOpExt	11 wsdl:binding after wsdl:operation element information items, if present.	11 This element information item serves as the head of a substitution group for extensibility elements that wish to appear as children of wsdl:binding after wsdl:operation
11bindingOpExt	11 wsdl:operation with wsdl:binding [parent]	11 This element information item serves as the head of a substitution group for extensibility elements that wish to appear as children of wsdl:operation appearing as children of wsdl:binding
11bindingOpMsgExt	11 wsdl:input with wsdl:operation [parent] which itself has wsdl:binding [parent] wsdl:output with wsdl:operation [parent] which itself has wsdl:binding [parent]	11 This element information item serves as the head of a substitution group for extensibility elements that wish to appear as children of wsdl:input or wsdl:output when they appear as children of wsdl:operation which itself appears as a child of wsdl:binding
11bindingOpFaultExt	11 wsdl:fault with wsdl:operation [parent] which itself has wsdl:binding [parent]	11 This element information item serves as the head of a substitution group for extensibility elements that wish to appear as children of wsdl:fault when it appears as a child of wsdl:operation which itself appears as a child of wsdl:binding
31Abstract elements related to service
11serviceExt	11 wsdl:service	11 This element information item serves as the head of a substitution group for extensibility elements that wish to appear as children of wsdl:service
11servicePrePortExt	11 wsdl:service before wsdl:port element information items, if present.	11 This element information item serves as the head of a substitution group for extensibility elements that wish to appear as children of wsdl:service before wsdl:port
11servicePostPortExt	11 wsdl:service after wsdl:port element information items, if present.	11 This element information item serves as the head of a substitution group for extensibility elements that wish to appear as children of wsdl:service after wsdl:port
11portExt	11 wsdl:port	11 This element information item serves as the head of a substitution group for extensibility elements that wish to appear as children of wsdl:port

Base type for extensibility elements

<xs:complexType name='ExtensibilityElement' abstract='true' >
  <xs:attribute ref='wsdl:required' use='optional' />
</xs:complexType>
	  
	  

Mandatory extensions[top]

Extension elements can be marked as mandatory by annotating them with a wsdl:required attribute information item (see [ ]) with a value of true. Mandatory extensions are those that MUST be processed correctly by the WSDL processor. If a mandatory extension element is processed, the WSDL processor MUST either agree to fully abide by all the rules and semantics signaled by the extension element's qualified name, or immediate cease processing (fault). In particular, if the WSDL processor does not recognize the qualified name of the extension element, it MUST fault. If the WSDL processor recognizes the qualified name, and determines that the extension in question is incompatible with any other aspect of the document (including other required extensions), it MUST fault.

required attribute information item[top]

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

• A [local name] of required.

• A [namespace name] of http://www.w3.org/2003/03/wsdl.

• A [specified] property with a value of true.

The type of the required is xs:boolean.