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<document>

 <properties>
  <title>Texen</title>
  <author email="dev@velocity.apache.org">Velocity Documentation Team</author>
 </properties>

<body>

<section name="What is Texen?" href="WhatisTexen?">

<p>
    Texen is a general purpose text generating utility. It is capable of
    producing almost any sort of text output. Driven by Ant, essentially
    an <a href="http://ant.apache.org/">Ant</a> Task, Texen uses
    a control template, an optional set of worker templates, and control
    context to govern the generated output. Although TexenTask can be
    used directly, it is usually subclassed to initialize your control
    context before generating any output.
</p>

<p>
    Texen was created to deal with the source generating requirements
    of the Turbine web application framework. The <a
    href="http://db.apache.org/torque/">Torque</a> uses a subclass of
    the TexenTask to generate SQL and the Object-Relational mapping
    sources for its O/R layer.  This is only one example; you can
    use Texen to generate almost any sort of text output!
</p>

</section>

<section name="The TexenTask" href="TheTexenTask">

<p>
    This trivial example, which shows how to use Texen from an Ant
    build.xml, is intended to illustrate how the Texen mechanism works.
</p>

<p>
<strong>Ant Build File</strong>
</p>

<source><![CDATA[
<project name="HtmlGenerator" default="main" basedir=".">

  <taskdef name="texen" classname="org.apache.texen.ant.TexenTask"/>

  <!-- ============================================================= -->
  <!-- G E N E R A T E  H T M L  P A G E S                           -->
  <!-- ============================================================= -->
  <!-- This target will generate a set of HTML pages based on        -->
  <!-- the information in our control context.                       -->
  <!-- ============================================================= -->

  <target name="main">

    <echo message="+------------------------------------------+"/>
    <echo message="|                                          |"/>
    <echo message="| Generating HTML pages!                   |"/>
    <echo message="|                                          |"/>
    <echo message="+------------------------------------------+"/>

    <texen
      controlTemplate="Control.vm"
      outputDirectory="."
      templatePath="."
      outputFile="generation.report"
    />

  </target>

</project>
]]></source>

<p>
<strong>Control Template</strong>
</p>

<source><![CDATA[
#*

file: Control.vm

This is the control template for our HTML
page generator!

*#

#set ($Planets = ["Earth", "Mars", "Venus"])

#foreach ($planet in $Planets)

    #set ($outputFile = $strings.concat([$planet, ".html"]))
    $generator.parse("HtmlTemplate.vm", $outputFile, "planet", $planet)

#end
]]></source>

<p>
<strong>Worker Template</strong>
</p>

<source><![CDATA[
#*

file: HtmlTemplate.vm

This is worker template. It is called by the
control template to produce useful output (or
not so useful in this case). :-)

*#

#set ($bgcolor = "#ffffff")

<html>
  <head>
    <title>
      Everything you wanted to know about $planet!
    </title>
  </head>
  <body bgcolor="$bgcolor">

  $planet is a great place to live!

  </body>
</html>
]]></source>

<p>
    Texen produces three html pages: Earth.html, Mars.html, and
    Venus.html. To do something more useful, you would subclass the
    TexenTask, place some objects in the control context, and use the
    information placed in the control context to generate useful output.
</p>

<p>
    See the Torque utility in Turbine for a full working example of
    Texen. A standalone version of Torque is available <a
    href="http://db.apache.org/torque/">here</a>.
</p>

    <table border="0">
        <tr>
            <th>Name</th>
            <th>Description</th>
        </tr>
        <tr>
            <td>templatePath</td>
            <td><b>[REQUIRED]</b>
            Set the path where Velocity will look
            for templates using the file template
            loader.
            <b>This is only required if useClasspath is not turned on.</b></td>
        </tr>
        <tr>
            <td>useClasspath</td>
            <td><b>[REQUIRED]</b>
            Set the use of the classpath in locating templates.
            true means the classpath will be used.
            <b>This is only required if templatePath is not set.</b></td>
        </tr>
        <tr>
            <td>useResourceLoaderCache</td>
            <td>Optional argument used when useClasspath is turned on.
            See the <a
            href="developer-guide.html#configuring_resource_loaders">Developer's Guide</a>
            for details on resource caching.</td>
        </tr>
        <tr>
            <td>resourceLoaderModificationCheckInterval</td>
            <td>Optional argument used when useClasspath is turned on.
            See the <a
            href="developer-guide.html#configuring_resource_loaders">Developer's Guide</a>
            for details on resource caching.</td>
        </tr>
        <tr>
            <td>controlTemplate</td>
            <td><b>[REQUIRED]</b>
            Set the control template for the
            generating process.</td>
        </tr>
        <tr>
            <td>outputDirectory</td>
            <td><b>[REQUIRED]</b>
            Set the output directory. It will be
            created if it doesn't exist.</td>
        </tr>
        <tr>
            <td>outputFile</td>
            <td><b>[REQUIRED]</b>
            Set the output file for the
            generation process.</td>
        </tr>
        <tr>
            <td>outputEncoding</td>
            <td>Set the output encoding.</td>
        </tr>
        <tr>
            <td>inputEncoding</td>
            <td>Set the input (template) encoding.</td>
        </tr>
        <tr>
            <td>contextProperties</td>
            <td>Set the context properties that will be
            fed into the initial context be the
            generating process starts.
            <p>
            We are going to do something special
            for properties that have a "file.contents"
            suffix: for these properties will pull
            in the contents of the file and make
            them available in the context. So for
            a line like the following in a properties file:
            <pre>license.file.contents = license.txt</pre>
            We will pull in the contents of license.txt
            and make it available in the context as
            $license. This should make texen a little
            more flexible.
            </p></td>
        </tr>
    </table>

</section>

<section name="Predefined Context Objects" href="PredefinedContextObjects">
<p>
    The Texen Ant task places several objects into the Context for you.
</p>
    <table border="0">
        <tr>
        <th>Name</th>
        <th>Value</th>
        </tr>
        <tr>
            <td>$generator</td>
            <td>
                This contains the the <a
                href ="api/org/apache/texen/Generator.html">Generator</a>
                instance used to output the text files.
            </td>
        </tr>
        <tr>
            <td>$outputDirectory</td>
            <td>
                This contains the the value of the outputDirectory property given to the Texen Ant Task.
            </td>
        </tr>
        <tr>
            <td>$strings</td>
            <td>
                This contains the an instance of a <a
                href="http://jakarta.apache.org/commons/lang/apidocs/org/apache/commons/lang/StringUtils.html">StringUtils</a>
                object.
            </td>
        </tr>
        <tr>
            <td>$files</td>
            <td>
                This contains the an instance of a <a
                href="api/org/apache/texen/util/FileUtil.html">FileUtil</a>
                object.
            </td>
        </tr>
        <tr>
            <td>$properties</td>
            <td>
                This contains the an instance of a <a
                href="api/org/apache/texen/util/PropertiesUtil.html">PropertiesUtil</a>
                object.
            </td>
        </tr>
    </table>

</section>

</body>
</document>
