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         -----------
         Creating a generic tag library with Autotag
         -----------

Creating a generic tag library

  A generic tag library is a jar file including the classes that implement
  the tags and a library descriptor <<<META-INF/template-suite.xml>>>, that can be used by
  Autotag to build specific tag libraries for Freemarker, JSP, and Velocity.
  
  The structure of the library descriptor is rather complex; fortunately 
  Autotag can generate it for you by parsing the sources.

* The tag class

  A tag in the library can be implemented by any java class that fits the following requirements:
  
  * The class name ends with <<<Model>>>.
  
  * It has a public, non-static, non-abstract method called <<<execute>>>.
  
  * The <<<execute>>> method returns <<<void>>>.
  
  * The parameters of the <<<execute>>> method are as follows:
  
  ** the first parameters may be anything you want; at runtime they will contain the values 
  assigned to the attributes of the tag in the template. Those parameters may be annotated with
  <<<org.apache.tiles.autotag.core.runtime.annotation.Parameter>>> in order to specify the name of
  the attribute, the default value, or to make the parameter mandatory.
  
  ** then, one parameter of type <<<org.apache.tiles.request.Request>>>.
  
  ** and finally, one optional parameter of type <<<org.apache.tiles.autotag.core.runtime.ModelBody>>>;
  at runtime it will contain the contents of the tag in the template.
  
  For instance:

----------------
public class MyTagModel {

    public void execute( 
        @Parameter(required=true) String mandatoryParam, 
        String optionalParam, 
        Request request, 
        ModelBody body) {
        ...
    }

}
----------------
  
* Generating the library descriptor

  the library descriptor can be generated using the create-descriptor goal of maven-autotag-plugin.
  
-----------------
<plugin>
  <groupId>org.apache.tiles.autotag.plugin</groupId>
  <artifactId>maven-autotag-plugin</artifactId>
  <version>1.0</version>
  <executions>
    <execution>
      <goals>
        <goal>create-descriptor</goal>
      </goals>
      <configuration>
        ...
      </configuration> 
    </execution>
  </executions>
</plugin>
-----------------

** Configuration reference

  [name] is the name of the tag library (for instance: <<<tiles>>>). It will be used for naming a
  number of generated files.
  
  [documentation] is a documentation that will be included in the library descriptor, and then 
  later in the appropriate artefacts when generating the taglibs.
  
  [includes] specifies what source files should be included, defaults to <<<**/*Model.java>>>.
  It follows the usual conventions in maven.
  
  [excludes] specifies what source files should be included, defaults to nothing.
  It follows the usual conventions in maven.
  
  [outputDirectory] specifies where to put the generated files, defaults to 
  <<<target/autotag-template-suite>>>.