xdocs/docs/anakia.xml

<?xml version="1.0" encoding="UTF-8"?>
<!--
 Licensed to the Apache Software Foundation (ASF) under one
 or more contributor license agreements.  See the NOTICE file
 distributed with this work for additional information
 regarding copyright ownership.  The ASF licenses this file
 to you 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.    
-->

<document>

 <properties>
  <title>Anakia</title>
  <author email="jon@latchkey.com">Jon S. Stevens</author>
 </properties>

<body>

<section name="What Is Anakia?" href="WhatIsAnakia?">
<p>
    Essentially an XML transformation tool, Anakia uses <a
    href="http://www.jdom.org">JDOM</a> and <a
    href="http://jakarta.apache.org/velocity">Velocity</a> to transform
    XML documents into the format of your choice. It provides an alternative to
    using Ant's &lt;style&gt; task and
    <a href="http://xml.apache.org/xalan/">XSL</a> to process XML
    files.
</p>
<p>
   The basic model that AnakiaTask uses is pretty straightforward :
</p>
   <ol>
   <li>Parse your XML into a JDOM Document:
<source><![CDATA[
SAXBuilder builder;
Document root = null;

try
{
    builder = new SAXBuilder(
        "org.apache.xerces.parsers.SAXParser" );
    root = builder.build( file );
}
catch( Exception E )
{
    System.out.println( ...  );
}
]]></source>

</li>

    <li>Stuff the Document (or root Element) into the context:<br/>
<source><![CDATA[
context.put("root", root );
]]></source>
</li>

    <li>Render a template using Velocity. Within the template, one
        can use JDOM's methods to access the data contained in the
        XML document.</li>
</ol>
<p>
    Anakia is potentially easier to learn than XSL, but it maintains a
    similar level of functionality. Learning cryptic &lt;xsl:&gt; tags
    is unnecessary; you only need to know how to use the provided
    Context objects, JDOM, and Velocity's simple directives. Anakia
    seems to perform much faster than Xalan's XSL processor at creating
    pages. (23 pages are generated in 7-8 seconds on a PIII 500mhz
    running Win98 and JDK 1.3 with client Hotspot. A similar system
    using Ant's &lt;style&gt; task took 14-15 seconds -- nearly a 2x
    speed improvement.)
</p>
<p>
    Anakia -- intended to replace Stylebook, which was originally used
    to generate simple, static web sites in which all pages had the same
    look and feel -- is great for documentation/project web sites, such
    as the sites on <a href="http://www.apache.org/">www.apache.org</a>
    and <a href="http://jakarta.apache.org">jakarta.apache.org</a>. As it
    is more targeted to a specific purpose, it does not provide some of
    XSL's &quot;extra&quot; functionality.
</p>
<p>
    The example in the jakarta-velocity/examples/anakia directory
    provides a good introduction to Anakia. You should find it quite
    simple to use.
</p>
<p>
    Anakia creates a Context, which contains a JDOM Document object of
    the .xml page, as well as an (optional) JDOM Document object of your
    project.xml page. In addition to the project.xml based context, additional
    xml contexts can be added through context nested elements. The
    .vsl page is executed (using Velocity) with the Context. You can then
    navigate your .xml file and pull information out of it by simply executing
    methods on the JDOM Document object.
</p>
<p>
    Anakia is being used to create the documentation for this
    website.  You can view the source for this website in the "xdocs" folder
    in the Velocity source distribution.
</p>

</section>

<section name="Installation/Example" href="Installation/Example">
<p>
    Before reviewing the jakarta-velocity/examples/anakia directory,
    you must <a href="../install.html">build Velocity</a>.
</p>
<p>
    After building Velocity, <code>cd</code> into the
    jakarta-velocity/examples/anakia/build directory and run 'ant'.
</p>
<p>
    Output from running ant, in this case HTML files, is placed
    into the jakarta-velocity/examples/anakia/docs/ directory.
</p>
<p>
    The jakarta-velocity/examples/anakia/xdocs/ directory has all of the
    .xml source code. The xdocs/stylesheets directory contains the .vsl
    file, in which most of the magic happens. Understanding <a
    href="user-guide.html">Velocity Template Language</a> and
    <a href="http://www.jdom.org/">JDOM</a> is
    necessary to understand how the .vsl file works.
</p>
</section>

<section name="How does it work?" href="Howdoesitwork?">

<p>
    Anakia is an Ant task that executes from an Ant build file. The
    build file looks something like this:
</p>

<source><![CDATA[
    <project name="build-site" default="docs" basedir=".">
    <property name="docs.src" value="../xdocs"/>
    <property name="docs.dest" value="../docs"/>

    <target name="prepare">
        <available classname="org.apache.velocity.anakia.AnakiaTask"
        property="AnakiaTask.present"/>
    </target>

    <target depends="prepare" name="prepare-error"
                            unless="AnakiaTask.present">
        <echo>
            AnakiaTask is not present! Please check to make sure that
            velocity.jar is in your classpath.
        </echo>
    </target>

    <target name="docs" depends="prepare-error"
                        if="AnakiaTask.present">
        <taskdef name="anakia"
                 classname="org.apache.velocity.anakia.AnakiaTask"/>
        <anakia basedir="${docs.src}" destdir="${docs.dest}/"
             extension=".html" style="./site.vsl"
             projectFile="./stylesheets/project.xml"
             excludes="**/stylesheets/**"
             includes="**/*.xml"
             lastModifiedCheck="false"
             velocityPropertiesFile="velocity.properties">
        </anakia>

        <copy todir="${docs.dest}/images" filtering="no">
            <fileset dir="${docs.src}/images">
                <include name="**/*.gif"/>
                <include name="**/*.jpeg"/>
                <include name="**/*.jpg"/>
            </fileset>
        </copy>
    </target>
</project>
]]></source>

    <table border="0">
        <tr>
            <th>Name</th>
            <th>Description</th>
        </tr>
        <tr>
            <td>basedir</td>
            <td>Specifies the path to the directory location of your
            .xml files.</td>
        </tr>
        <tr>
            <td>destdir</td>
            <td>Specifies the path to the directory where the output
            files should go.</td>
        </tr>
        <tr>
            <td>extension</td>
            <td>
            This is the extension that is appended to the end of your
            .xml file. For example, with an extension of ".html",
            index.xml would be converted into index.html. By default,
            the extension is .html.
            </td>
        </tr>
        <tr>
            <td>style</td>
            <td>This is the path (relative to Velocity's
            template.loader.1.template.path) to the
            VelocityStyleTemplate to process. This file is the
            equivalent to the .xsl file in Ant's style task. </td>
        </tr>
        <tr>
            <td>projectFile</td>
            <td>This is the path to a "project" file. This file is an
            XML file that can be used as a "navigation" file. If you
            have used Stylebook or Struts system for generation of the
            web site documentation, you will understand the purpose of
            this file. <strong>It is an optional task argument.</strong>
            If you look at the Anakia example in the
            jakarta-velocity/examples/anakia directory, you can see the
            project.xml file being used in the .vsl file. </td>
        </tr>
        <tr>
            <td>excludes</td>
            <td>This is the standard Ant excludes attribute. Specify any
            files or directories that you do not want Anakia to try to
            process.</td>
        </tr>
        <tr>
            <td>includes</td>
            <td>This is the standard Ant includes attribute. Specify any
            files or directories that you do want Anakia to try to
            process.</td>
        </tr>
        <tr>
            <td>lastModifiedCheck</td>
            <td>This turns on or off the ability to check the last
            modified date on files in order to determine whether or not
            they need to be re-rendered or not. The value of this
            attribute can be "true, false, yes, no". By default, it is
            true, meaning that the last modified date should be checked
            and if the original .xml file, project file, or .vsl file
            have not changed, then don't process the page. This
            accelerates processing because pages that have not changed
            will not get reprocessed.</td>
        </tr>
        <tr>
            <td>templatePath</td>
            <td>This is the path to the templateRoot which is the
            directory where your site.vsl file is located. This can be
            defined in the Velocity.properties or it can be defined
            here. It it an optional argument if it is defined in the
            Velocity properties file already. However, if defined, this
            value will override the path defined in the
            Velocity.properties file.</td>
        </tr>
        <tr>
            <td>velocityPropertiesFile</td>
            <td>This is the path to the velocity.properties file. It is
            an optional argument and by default is set to find the
            properties file in the same directory that the JVM was
            started in.</td>
        </tr>
    </table>
</section>

<section name="Predefined Context Objects" href="PredefinedContextObjects">
<p>
    The Anakia Ant task places several objects into the Context for you.
</p>
    <table border="0">
        <tr>
        <th>Name</th>
        <th>Value</th>
        </tr>
        <tr>
            <td>$root</td>
            <td>This contains the JDOM root Element to your .xml document. When
            this (or any other variable containing an element) are simply
            placed into template output, their XML form is rendered.</td>
        </tr>
        <tr>
            <td>$project</td>
            <td>This contains the JDOM root Element to your project.xml
            document. If you have not specified a project.xml document,
            then this variable will not be in the context. </td>
        </tr>
        <tr>
            <td>$escape.getText($string)</td>
            <td>This context object will convert HTML Entities in the
            $string that is passed into it and it will return the
            converted String. This is good for dealing with CDATA. The
            entities that are converted are: &quot; -> &amp;quot; | &lt;
            -> &amp;lt; | &gt; -> &amp;gt; | &amp; - > &amp;amp; </td>
        </tr>
        <tr>
            <td>$relativePath</td>
            <td>This contains a String which is the relative path to
            your .xml document from the baseDir that was specified in
            your Ant task attributes. Please see the examples/anakia
            .vsl document for example usage of this String.</td>
        </tr>
        <tr>
            <td>$xmlout</td>
            <td>This contains an class which extends the instance of the
            JDOM XMLOutputter() object. This allows you to easily create
            String output out of your JDOM element objects.
            $xmlout.outputString(Element). Again, please look at the
            examples for more information on how to use this
            object. NOTE: this object is obsoleted as simply specifying
            $element will output the XML serialized form of the element.</td>
        </tr>
        <tr>
            <td>$xmlout.outputString(Element, true)</td>
            <td>This contains an class which extends the instance of the
            JDOM XMLOutputter() object. The difference between this
            .outputString() and the one in XMLOutputter is that it will
            output all of the Elements <strong>within</strong> the
            passed in Element. So, if you pass in a &lt;td&gt; Element,
            you will get everything inside the &lt;td&gt; &lt;/td&gt;, but
            not the actual &lt;td&gt; &lt;/td&gt;. NOTE: this object is
            obsoleted as simply specifying $element.content will produce the
            desired output.
            </td>
        </tr>
        <tr>
            <td>$treeWalk.allElements($element)</td>
            <td>This will allow you to walk a tree of JDOM Element
            objects starting at $element. The point of this context
            object is to allow you to build an XSLT type system where
            you can look at each Element node conditionally and set its
            content and attribute values. This is probably one of the
            more &quot;ugly&quot; aspects of Anakia, but it does do the
            job and suggestions for improvement are appreciated. This
            context object is still under development and more
            documentation will follow soon. NOTE: this object is obsolete and
            is kept for backward compatibility only. You can use
            $element.selectNodes("//*") to achieve the same effect.</td>
        </tr>
        <tr>
            <td>$xpath.applyTo("document/properties/@title", $root)</td>
            <td>
               The W3C XPath Specification <a
               href="http://www.w3.org/TR/xpath/">http://www.w3.org/TR/xpath/
               </a> refers to NodeSets repeatedly, but this implementation
               simply uses java.util.List to hold all Nodes. A 'Node' is any
               object in a JDOM object tree, such as an org.jdom.Element,
               org.jdom.Document, or org.jdom.Attribute. Please see the .vsl
               example file and the org.apache.velocity.anakia.XPathTool javadoc
               for more information. NOTE: this object is obsolete and is kept
               for backward compatibility only. You can use
               $element.selectNodes("document/properties/@title") to achieve
               the same effect with a more intuitive syntax.
            </td>
        </tr>
        <tr>
            <td>$date</td>
            <td>
                This is a new java.util.Date object. Useful for putting
                the current date/time into a page.
            </td>
        </tr>
    </table>
<p>
    All node lists returned from Anakia objects through $element.selectNodes,
    $element.content, and $element.children, as well as through obsoleted
    $treeWalk.allElements and $xpath.applyTo have two special features:
    <ul>
        <li>they support the selectNodes method just as a single element does
        that applies an XPath expression to all nodes in the list, and</li>
        <li>when inserted into template output by simply specifying $list, they
        produce the XML fragment consisting of all nodes they contain. This
        eliminates much of the #foreach code in templates.</li>
    </ul>
</p>

</section>

<section name="Customizing the Anakia Context" href="CustomizingtheAnakiaContext">
<p>
    The Anakia context can be customized by using one or more context nested
    elements.
</p>
<source><![CDATA[
<anakia ...>
    <context name="customContext" file="./customContext.xml"/>
</anakia>
]]></source>
<p>
    The context file must be an xml file and is an instance of a JDOM
    root element similar to $project. There are two attributes for the context:
</p>
<table border="0">
    <tr>
        <th>Name</th>
        <th>Description</th>
    </tr>
    <tr>
        <td>name</td>
        <td>
            This sets the name of the context within the velocity context.
            It cannot be one of the predefined context objects.
        </td>
    </tr>
    <tr>
        <td>file</td>
        <td>
            The location of the custom file relative to the anakia basedir.
            This must be an XML file.
        </td>
    </tr>
</table>
<p>
    Within the velocity template the context can be accessed using the standard
    velocity template language.
</p>
<source><![CDATA[
#set ($customMenus = $xpath.applyTo("body/menu",$customContext))
#foreach($customMenu in $customMenus)
  <strong>$customMenu.getAttributeValue("name")</strong>
  <ul>
  #foreach ($customItem in $customMenu.getChildren() )
    #set ($name = $customItem.getAttributeValue("name"))
    <li>#projectanchor($name $customItem.getAttributeValue("href"))</li>
  #end
  </ul>
#end]]></source>
</section>

<section name="Credits" href="Credits">
<p>
    Anakia was originally conceptualized and implemented by
        <a href="mailto:jon@latchkey.com">Jon S. Stevens</a>.
</p>
<p>
    The name <a
    href="http://www.kabalarians.com/female/anakia.htm">Anakia</a> is a
    cool name that I think fits this project quite nicely. "The name of
    Anakia has given you the desire for creative, artistic or musical
    expression in an original way. You strive to be different and have
    the self-confidence to implement your ideas because you have the
    perseverance necessary to see something through, despite obstacles."
</p>
<p>
    Further help and assistance was provided by Jason van Zyl and Geir
    Magnusson Jr. XPath support was added by Bob McWhirter. The more
    intuitive syntax achieved through selectNodes() and self-rendering
    elements and node lists was added by Attila Szegedi. The custom context
    nested element was added by Peter Ryan.
</p>

</section>

</body>
</document>