- From: David Booth <dbooth@dev.w3.org>
- Date: Mon, 20 Dec 2004 17:15:59 +0000
- To: public-ws-desc-eds@w3.org
Update of /sources/public/2002/ws/desc/wsdl20 In directory hutz:/tmp/cvs-serv29802 Modified Files: wsdl20-primer.xml wsdl20-primer.html Log Message: fixed broken fragid Index: wsdl20-primer.xml =================================================================== RCS file: /sources/public/2002/ws/desc/wsdl20/wsdl20-primer.xml,v retrieving revision 1.27 retrieving revision 1.28 diff -C2 -d -r1.27 -r1.28 *** wsdl20-primer.xml 20 Dec 2004 16:55:31 -0000 1.27 --- wsdl20-primer.xml 20 Dec 2004 17:15:57 -0000 1.28 *************** *** 1119,1123 **** <div2 id="adv-extensibility"> <head>Extensibility</head> ! <p>WSDL 2.0 provides two extensibility mechanisms: an open content model, which allows XML elements and attributes from other (non-wsdl) XML namespaces to be interspersed into a WSDL document; and <xspecref href="&w3c-designation-part1;#Features">Features</xspecref> and <xspecref href="&w3c-designation-part1;#Properties">Properties</xspecref>. Both mechanisms use URIs to identify the semantics of the extensions. For extension XML elements and attributes, the namespace URI of the extension element or attribute acts as an unambiguous name for the semantics of that extension. For Features and Properties, the Feature or Property is named by a URI.</p><p>In either case, the URI that identifies the semantics of an extension SHOULD be dereferenceable to a document that describes the semantics of that extension. As of this writing, there is no generally accepted standard for what kind of document that should be. However, the <loc href="http://www.w3.org/2001/tag/">W3C TAG</loc> has been discussing the isue (see TAG issue <loc href="http://www.w3.org/2001/tag/issues.html?type=1#namespaceDocument-8">namespaceDocument-8</loc>) and is likely to provide guidance at some point.</p><div3 id="adv-optional-versus-required"><head>Optional Versus Required Extensions</head><p>Extensions can either be required or optional: An <emph>optional</emph> extension is one that the requester agent may either engage or ignore, entirely at its discretion, and is signaled by attribute <code>wsdl:required="false"</code>; whereas a <emph>required</emph> extension is one that MUST be supported and engaged by the requester agent in order for the interaction to succeed properly, and is signaled by attribute <code>wsdl:required="true"</code>. </p><p>The optionality signaled by <code>wsdl:required="false"</code> pertains only to the <emph>requester</emph> agent -- not the provider agent. The provider agent MUST support both optional and required extensions that it advertises in its WSDL document. </p><p>A WSDL processor (acting to ealize a requester agent) need not support every conceivable required extension, but if it sees a required extension that it does not recognize or does not support, then it MUST fault. </p></div3><div3 id="adv-scope-of-wsdl-required"><head>Scoping of the wsdl:required Attribute</head><ednote><edtext>To do: Need to check the scoping rules to see if this is correct.</edtext></ednote><p>As a convenience mechanism, the <code>wsdl:required</code> attribute need not be specified on every extension element. If it is omitted from an extension element, its effective value is inherited from the smallest enclosing scope that explicitly sets its value. If there is no enclosing scope that explicitly sets its value, then its value defaults to <code>false</code>. </p><p>Because portions of a Web service description can be written in different physical documents by different people, one should be cautious about setting <code>wsdl:required="false"</code> when an outer scope, written by someone else, had set <code>wsdlrequired="true"</code>.</p></div3></div2><div2 id="adv-FP"> <head>Features and Properties</head> --- 1119,1123 ---- <div2 id="adv-extensibility"> <head>Extensibility</head> ! <p>WSDL 2.0 provides two extensibility mechanisms: an open content model, which allows XML elements and attributes from other (non-wsdl) XML namespaces to be interspersed into a WSDL document; and <xspecref href="&w3c-designation-part1;#Feature">Features</xspecref> and <xspecref href="&w3c-designation-part1;#Property">Properties</xspecref>. Both mechanisms use URIs to identify the semantics of the extensions. For extension XML elements and attributes, the namespace URI of the extension element or attribute acts as an unambiguous name for the semantics of that extension. For Features and Properties, the Feature or Property is named by a URI.</p><p>In either case, the URI that identifies the semantics of an extension SHOULD be dereferenceable to a document that describes the semantics of that extension. As of this writing, there is no generally accepted standard for what kind of document that should be. However, the <loc href="http://www.w3.org/2001/tag/">W3C TAG</loc> has been discussing the issu (see TAG issue <loc href="http://www.w3.org/2001/tag/issues.html?type=1#namespaceDocument-8">namespaceDocument-8</loc>) and is likely to provide guidance at some point.</p><div3 id="adv-optional-versus-required"><head>Optional Versus Required Extensions</head><p>Extensions can either be required or optional: An <emph>optional</emph> extension is one that the requester agent may either engage or ignore, entirely at its discretion, and is signaled by attribute <code>wsdl:required="false"</code>; whereas a <emph>required</emph> extension is one that MUST be supported and engaged by the requester agent in order for the interaction to succeed properly, and is signaled by attribute <code>wsdl:required="true"</code>. </p><p>The optionality signaled by <code>wsdl:required="false"</code> pertains only to the <emph>requester</emph> agent -- not the provider agent. The provider agent MUST support both optional and required extensions that it advertises in its WSDL document. </p><p>A WSDL processor (acting to reaize a requester agent) need not support every conceivable required extension, but if it sees a required extension that it does not recognize or does not support, then it MUST fault. </p></div3><div3 id="adv-scope-of-wsdl-required"><head>Scoping of the wsdl:required Attribute</head><ednote><edtext>To do: Need to check the scoping rules to see if this is correct.</edtext></ednote><p>As a convenience mechanism, the <code>wsdl:required</code> attribute need not be specified on every extension element. If it is omitted from an extension element, its effective value is inherited from the smallest enclosing scope that explicitly sets its value. If there is no enclosing scope that explicitly sets its value, then its value defaults to <code>false</code>. </p><p>Because portions of a Web service description can be written in different physical documents by different people, one should be cautious about setting <code>wsdl:required="false"</code> when an outer scope, written by someone else, had set <code>wsdl:reuired="true"</code>.</p></div3></div2><div2 id="adv-FP"> <head>Features and Properties</head> Index: wsdl20-primer.html =================================================================== RCS file: /sources/public/2002/ws/desc/wsdl20/wsdl20-primer.html,v retrieving revision 1.14 retrieving revision 1.15 diff -C2 -d -r1.14 -r1.15 *** wsdl20-primer.html 20 Dec 2004 16:58:28 -0000 1.14 --- wsdl20-primer.html 20 Dec 2004 17:15:57 -0000 1.15 *************** *** 2734,2740 **** (non-wsdl) XML namespaces to be interspersed into a WSDL document; and <a href= ! "http://www.w3.org/TR/2004/WD-wsdl20-20040803#Features">Features</a> and <a href= ! "http://www.w3.org/TR/2004/WD-wsdl20-20040803#Properties">Properties</a>. Both mechanisms use URIs to identify the semantics of the extensions. For extension XML elements and attributes, the --- 2734,2740 ---- (non-wsdl) XML namespaces to be interspersed into a WSDL document; and <a href= ! "http://www.w3.org/TR/2004/WD-wsdl20-20040803#Feature">Features</a> and <a href= ! "http://www.w3.org/TR/2004/WD-wsdl20-20040803#Property">Properties</a>. Both mechanisms use URIs to identify the semantics of the extensions. For extension XML elements and attributes, the
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