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| <!DOCTYPE document PUBLIC "-//APACHE//DTD Documentation V1.3//EN" "http://forrest.apache.org/dtd/document-v13.dtd"> |
| |
| <document> |
| <header> |
| <title>Apache™ FOP Development: Adding an Extension</title> |
| <version>$Revision$</version> |
| </header> |
| <body> |
| <section id="overview"> |
| <title>Overview</title> |
| <p>For documentation of standard Apache™ FOP extensions, see the <link href="../trunk/extensions.html">User FOP Extensions</link> document.</p> |
| <p> |
| If the default funtionality of FOP needs to be extended for |
| some reason then you can write an extension. |
| </p> |
| <p>There are three types of extensions possible:</p> |
| <ul> |
| <li>An output document extension such as the PDF bookmarks</li> |
| <li>an instream-foreign-object extensions such as SVG</li> |
| <li>an fo extension that creates an area in the area tree where normal xsl:fo is not possible</li> |
| </ul> |
| </section> |
| <section id="adding"> |
| <title>Adding Your Own</title> |
| <p> |
| To add your own extension you need to do the following things. |
| </p> |
| <ol> |
| <li>Write code that implements your extension functionality. The easiest place to |
| start is by looking at the code in org.apache.fop.fo.extensions, and by looking at the examples in the <code>examples</code> directory.</li> |
| <li>Create a class that extends the abstract org.apache.fop.fo.ElementMapping class. ElementMapping is a hashmap of all of the elements in a particular namespace, which makes it easier for FOP to create a different object for each element. |
| ElementMapping objects are static to save on memory. |
| They are loaded by FOP when parsing starts to validate input.</li> |
| <li>Create the following file: "/META-INF/services/org.apache.fop.fo.ElementMapping", which should contain the fully qualified classname of your ElementMapping implementation class.</li> |
| <li>Create a jar file containing all of the above files.</li> |
| <li>Create your XSL-FO file with the extra XML data embedded in the file with the |
| correct name space. |
| The examples for SVG and pdfoutline.fo show how this can be done. |
| The pdf documents on the FOP site use this extension. |
| See also <link href="../examples.html">Examples</link> for more examples.</li> |
| <li>Put your jar file in the classpath</li> |
| <li>Run FOP using your XSL-FO file as input.</li> |
| </ol> |
| </section> |
| </body> |
| </document> |
