DITA Open Toolkit

Creating a new plug-in extension point

If your plug-in needs to define its own extension point in an XML file, add the string "_template" to the filename before the file suffix. During integration, this file will be processed like the built-in DITA-OT templates.

Template files are used to integrate most DITA-OT extensions. For example, the file dita2xhtml_template.xsl contains all of the default rules for converting DITA topics to XHTML, along with an integration point for plug-in extensions. When the integrator runs, the file dita2xhtml.xsl is recreated, and the integration point is replaced with references to all appropriate plug-ins.

To mark a new file as a template file, use the <template> element.

The template extension namespace has the URI http://dita-ot.sourceforge.net. It is used to identify elements and attributes that have a special meaning in template processing. This documentation uses a prefix of  dita:  for referring to elements in the template extension namespace. However, template files are free to use any prefix, provided that there is a namespace declaration that binds the prefix to the URI of the template extension namespace.

dita:extension element

The dita:extension elements are used to insert generated content during integration process. There are two required attributes:

  • The id attribute defines the extension point ID which provides the argument data.
  • The behavior attribute defines which processing action is used.

Supported values for behavior attribute:

org.dita.dost.platform.CheckTranstypeAction
Create Ant condition elements to check if the ${transtype} property value equals a supported transformation type value.
org.dita.dost.platform.ImportAntLibAction
Create Ant pathelement elements for library imported extension point. The id attribute is used to define the extension point ID.
org.dita.dost.platform.ImportPluginCatalogAction
Include plug-in metadata catalog content.
org.dita.dost.platform.ImportPluginInfoAction
Create plug-in metadata Ant properties.
org.dita.dost.platform.ImportStringsAction
Include plug-in string file content base on generated text extension point. The id attribute is used to define the extension point ID.
org.dita.dost.platform.ImportXSLAction
Create xsl:import elements based on XSLT import extension point. The id attribute is used to define the extension point ID.
org.dita.dost.platform.InsertAction
Include plug-in conductor content based on Ant import extension point. The id attribute is used to define the extension point ID.
org.dita.dost.platform.InsertAntActionRelative
Include plug-in conductor content based on relative Ant import extension point. The id attribute is used to define the extension point ID.
org.dita.dost.platform.InsertCatalogActionRelative
Include plug-in catalog content based on catalog import extension point. The id attribute is used to define the extension point ID.
org.dita.dost.platform.ListTranstypeAction
Create a pipe delimited list of supported transformation types.

dita:extension attribute

The dita:extension attribute is used to process attributes in elements which are not in template extension namespace. The value of the attribute is a space delimited tuple, where the first item is the name of the attribute to process and the second item is the action ID.

Supported values:

depends org.dita.dost.platform.InsertDependsAction
Ant target dependency list is processed to replace all target names which start with an open curly bracket and end with a close curly bracket. The value of the extension point is the ID between the curly brackets.

Example

The following plug-in defines myBuildFile_template.xml as a new template for extensions, and two new extension points.

<plugin id="com.example.new-extensions">
  <extension-point id="com.example.new-extensions.pre"
                   name="Custom target preprocess"/>
  <extension-point id="com.example.new-extensions.content"
                   name="Custom target content"/>
  <template file="myBuildFile_template.xml"/>
</plugin>

When the integrator runs, this will be used to recreate myBuildFile.xml, replacing Ant file content based on extension point use.

<project xmlns:dita="http://dita-ot.sourceforge.net">
  <target name="dita2custom"
          depends="dita2custom.init,
                   {com.example.new-extensions.pre},
                   dita2xhtml"
          dita:extension="depends org.dita.dost.platform.InsertDependsAction">
    <dita:extension id="com.example.new-extensions.content"
                    behavior="org.dita.dost.platform.InsertAction"/>
  <target>
</project>