<?xml version="1.0" standalone="no"?>
<!DOCTYPE s1 SYSTEM "../../style/dtd/document.dtd">

<!--
 * Copyright 1999-2004 The Apache Software Foundation.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
-->
<!-- $Id: extensions_xsltc.xml 337884 2004-02-17 19:29:35Z minchau $ -->

<s1 title="Extensions for &xslt4jc-short;">
<ul>
<li><link anchor="intro">Introduction</link></li>
<li><link anchor="constraints">Constraints</link></li>
<li><link anchor="java_ext">Java extension</link></li>
<li><link anchor="exslt_ext">EXSLT extensions</link></li>
<li><link anchor="nodeset_ext">nodeset</link></li>
<li><link anchor="redirect_ext">output/redirect</link></li>
</ul>
<anchor name="intro"/>
  <s2 title="Introduction">
  <p>&xslt4jc-short; supports the use of extension functions implemented in external Java classes. It also
  supports the <link anchor="nodeset_ext">nodeset</link>, <link anchor="redirect_ext">output/redirect</link> 
  and <link anchor="exslt_ext">EXSLT</link> extension functions. Extension support in &xslt4jc-short; is
  still under development. It is currently not as complete as the extension support in the
  &xslt4j; Interpretive processor. There are constraints in some areas.</p>
  </s2>

<anchor name="constraints"/>
  <s2 title="Constraints">
  <p>In addition to the constraints listed below for each particular extension, extension support
  in &xslt4jc-short; also has the following limitations:</p>
  <ol>
  <li><link idref="extensions" anchor="ext-elements">Extension element</link> is not supported.
  The extension element mechanism is closely related to the internal implementation of the XSLT processor.
  The current extension element mechansim is designed for the &xslt4ji; processor. It does not work with &xslt4jc-short;.</li>
  <li>The <link idref="extensions" anchor="supported-lang">xalan:component and xalan:script</link> extension elements are not supported at the moment. This has
  the implication that you cannot use scripting languages (e.g. javascript) with &xslt4jc-short;.</li>
  <li><link idref="extensionslib" anchor="sql">The SQL extension</link> is not supported in &xslt4jc-short; at the moment.</li>
  </ol>
  </s2>
  
<anchor name="java_ext"/>
  <s2 title="Java extension">
  <p>Java extension is supported in &xslt4jc-short;. Constructors, static and instance methods are all supported.
  You can use any of the <link idref="extensions" anchor="ext-func-calls">three namespace formats</link>
   (Java, package and class) in your stylesheet.
  </p>
  <p>The official namespace for the Java extension is <code>http://xml.apache.org/xalan/java</code>. The old &xslt4jc-short; Java namespace
  <code>http://xml.apache.org/xalan/xsltc/java</code> and the old &xslt4j; namespace <code>http://xml.apache.org/xslt/java</code>
  are also supported for backward compatibility.</p>
  <p>All usage syntax for the &xslt4j; Interpretive processor also applies to &xslt4jc-short; with only one 
  exception: &xslt4jc-short; does not support the notion of default object 
  in <link idref="extensions" anchor="ext-func-calls">class format namespace</link>. 
  When using instance methods, you should always specify the class instance as the first argument
  to the extension function.</p>
  <p>The following example shows you how to call constructors, static, and nonstatic functions,
  using different namespace formats:</p>

  <source>&lt;xsl:stylesheet version=&quot;1.0&quot;
    xmlns:xsl=&quot;http://www.w3.org/1999/XSL/Transform&quot;
    xmlns:date=&quot;http://xml.apache.org/xalan/java/java.util.Date&quot;
    xmlns:java_lang=&quot;http://xml.apache.org/xalan/java/java.lang&quot;
    exclude-result-prefixes=&quot;date java_lang&quot;&gt;

  &lt;!--
  * test: construction of Date object using a parameter calculated
  *       by a static call to the java.lang.Math object. Then call
  *       a non-static method (getTime()) on the newly created Date
  *       object. Demonstrates calling constructors, static functions
  *       (Math.max) and non-static functions (getTime()).
  *
  * Output:
  *   &lt;?xml version=&quot;1.0&quot; encoding=&quot;UTF-8&quot;?&gt;
  *     Date of object: Sat Nov 30 17:32:41 EST 2002
  *     Time of object: 1038695561000
  *
  --&gt;

  &lt;xsl:template match=&quot;/&quot;&gt;
   &lt;!-- create Date object with calculated parameter --&gt;
   &lt;xsl:variable name=&quot;dateObject&quot;
     select=&quot;date:new(
         java_lang:Math.max(1027695561000,1038695561000)
     )&quot;/&gt;
   Date of object: &lt;xsl:value-of select=&quot;$dateObject&quot;/&gt;
   Time of object: &lt;xsl:value-of select=&quot;date:getTime($dateObject)&quot;/&gt;
  &lt;/xsl:template&gt;

  &lt;/xsl:stylesheet&gt;
  </source>
  <note>Always use the abbreviated syntax for Java extension, because the xalan:component/xalan:script
  constructs are not supported in &xslt4jc-short;.</note>
  </s2>
  
<anchor name="exslt_ext"/>
  <s2 title="EXSLT extensions">
  <p>The following EXSLT extension modules are supported in &xslt4jc-short;:</p>
  <ul>
  <li><jump href="apidocs/org/apache/xalan/lib/ExsltCommon.html">EXSLT common functions</jump></li>
  <li><jump href="apidocs/org/apache/xalan/lib/ExsltMath.html">EXSLT math functions</jump></li>
  <li><jump href="apidocs/org/apache/xalan/lib/ExsltSets.html">EXSLT set functions</jump></li>
  <li><jump href="apidocs/org/apache/xalan/lib/ExsltDatetime.html">EXSLT date-and-time functions</jump></li>
  <li><jump href="apidocs/org/apache/xalan/lib/ExsltStrings.html">EXSLT string functions</jump></li>
  </ul> 
  <p>The functions in the <jump href="apidocs/org/apache/xalan/lib/ExsltDynamic.html">dynamic</jump> module 
  (e.g. evaluate) are not supported because of the &xslt4jc-short; design limitation.
  Work is currently underway on <jump href="http://www.exslt.org/func/elements/function/index.html">user 
  defined EXSLT functions (with the function and result elements)</jump>.</p>
  <p>The <code>nodeset</code> and <code>objectType</code> extension functions in the <jump href="apidocs/org/apache/xalan/lib/ExsltCommon.html">common</jump> 
  module are implemented natively in &xslt4jc-short;. For all other EXSLT extension functions,
  &xslt4jc-short; uses the same implementation as the &xslt4j; Interpretive processor. The implementation classes 
  are under <code>org.apache.xalan.lib</code>.
  Depending on the packaging, these classes can be in a separate jar file (e.g. xalan.jar) from
  the &xslt4jc-short; classes. In this case you need to add the jar file containing the EXSLT classes to your
  classpath in order to use EXSLT extensions in &xslt4jc-short;.</p>
  </s2>
  
<anchor name="nodeset_ext"/>
  <s2 title="nodeset">
  <p>&xslt4jc-short; also supports the nodeset() extension function for transforming an RTF (result 
    tree fragment) into a node set.</p>
    <p>The nodeset extension can be used as an &xslt4jc-short; extension function in the namespace
    <code>http://xml.apache.org/xalan/xsltc</code>, a &xslt4j; extension function in the namespace
    <code>http://xml.apache.org/xalan</code>, an EXSLT extension function in the namespace 
    <code>http://exslt.org/common</code> or as a standard XPATH function. When it is used as
    an EXSLT extension function, you need to refer to the nodeset extension function as 
    <code>node-set</code>.</p>
    <p>The following exmaple shows you how to use the nodeset extension
    function in different namespaces:</p>
    <source>&lt;xsl:stylesheet xmlns:xsl=&quot;http://www.w3.org/1999/XSL/Transform&quot;        
  xmlns:xsltc-extension=&quot;http://xml.apache.org/xalan/xsltc&quot;
  xmlns:xalan=&quot;http://xml.apache.org/xalan&quot;
  xmlns:exslt=&quot;http://exslt.org/common&quot;
  version=&quot;1.0&quot;&gt;
  &lt;xsl:template match=&quot;/&quot;&gt;
    &lt;xsl:variable name=&quot;rtf&quot;&gt;
      &lt;docelem&gt;
        &lt;elem1&gt;elem1&lt;/elem1&gt;
        &lt;elem2&gt;elem2&lt;/elem2&gt;
      &lt;/docelem&gt;
    &lt;/xsl:variable&gt;
    &lt;!-- Use nodeset as an XSLTC extension function --&gt;
    &lt;xsl:value-of select=&quot;xsltc-extension:nodeset($rtf)/docelem/elem1&quot;/&gt;
    &lt;!-- Use nodeset as a &xslt4j; extension function --&gt;
    &lt;xsl:value-of select=&quot;xalan:nodeset($rtf)/docelem/elem1&quot;/&gt;
    &lt;!-- Use nodeset as an EXSLT extension function --&gt;
    &lt;xsl:value-of select=&quot;exslt:node-set($rtf)/docelem/elem1&quot;/&gt;
    &lt;!-- Use nodeset as standard function --&gt;
    &lt;xsl:value-of select=&quot;nodeset($rtf)/docelem/elem1&quot;/&gt;
  &lt;/xsl:template&gt; 
&lt;/xsl:stylesheet&gt;
</source><br/>
<note>The preferred solution is to use the EXSLT node-set function so that it can work
with multiple XSLT processors.</note>
  </s2>
  
<anchor name="redirect_ext"/>
  <s2 title="output/redirect">
  <p>&xslt4jc-short; supports the output extension element for redirecting the output to one 
  or more files. The output extension element is also aliased to the write extension element 
  in the namespace <code>http://xml.apache.org/xalan/redirect</code>. Therefore you can use
  it in the same way as the <link idref="extensionslib" anchor="redirect">redirect</link> 
  extension in &xslt4j;.</p>
  <p>You can use the file and append attributes with the output/redirect extension. The value of the file
  attribute is an attribute value template. If the value of the append attribute is true or yes, the
  output is appended to the file rather than overwriting the file.</p>
  <p>The following example shows you how to use the output/redirect extension:</p>
    <source> &lt;xsl:stylesheet 
   xmlns:xsl=&quot;http://www.w3.org/1999/XSL/Transform&quot;
   xmlns:xsltc=&quot;http://xml.apache.org/xalan/xsltc&quot;
   xmlns:redirect=&quot;http://xml.apache.org/xalan/redirect&quot;
   extension-element-prefixes=&quot;xsltc redirect&quot;
   version=&quot;1.0&quot;&gt;
   &lt;xsl:template match=&quot;/&quot;&gt;
     &lt;xsl:text&gt;This goes to standard output&lt;/xsl:text&gt;
     &lt;xsltc:output file=&quot;blob.xml&quot;&gt;
       &lt;xsl:text&gt;This ends up in the file 'blob.xml'&lt;/xsl:text&gt;
     &lt;/xsltc:output&gt;
     &lt;redirect:write file=&quot;blob2.xml&quot;&gt;
       &lt;xsl:text&gt;This ends up in the file 'blob2.xml'&lt;/xsl:text&gt;
     &lt;/redirect:write&gt;
   &lt;/xsl:template&gt;
&lt;/xsl:stylesheet&gt;</source>  
  </s2>

</s1>
