Features

Cocoon 3 consists of 3 layers. Each of this layers is packaged as separate module:

cocoon-pipeline
cocoon-sitemap
cocoon-servlet

Additionally there are more optional modules:

cocoon-stringtemplate
cocoon-controller
cocoon-rest

Cocoon Pipeline

This module doesn't have any third-party dependencies. Currently it provides three pipeline implementations:

noncaching
caching
async-caching

and it provides a basic set of SAX components:

FileGenerator
XSLTTransformer
XMLSerializer
IncludeTransformer
CleaningTransformer
FileReader
StringGenerator

Here is an example:

Pipeline<SAXPipelineComponent> pipeline = new NonCachingPipeline<SAXPipelineComponent>();
pipeline.addComponent(new XMLGenerator("<x></x>"));
pipeline.addComponent(new XSLTTransformer(this.getClass().getResource("/test1.xslt")));
pipeline.addComponent(new XMLSerializer());

ByteArrayOutputStream baos = new ByteArrayOutputStream();
pipeline.setup(baos);
pipeline.execute();

Cocoon Sitemap

A sitemap connects a request (not necessarily a servlet request!) with a pipeline. Here is an example:

<?xml version="1.0" encoding="UTF-8"?>
<map:sitemap xmlns:map="http://apache.org/cocoon/sitemap"
  xmlns:servlet="http://apache.org/cocoon/servlet">
  <map:pipelines>
    <map:pipeline>
      <map:match pattern="screen/video">
        <map:generate src="video.xml" type="stringtemplate" />
        <map:serialize type="xml" />
      </map:match>
    </map:pipeline>
  </map:pipelines>
</map:sitemap>

Cocoon Servlet

This module provides a servlet that connects an HTTP request with a sitemap. It works smoothly within the Servlet-Service framework. The Servlet-Service framework enables the inter-sitemap communication and provides polomorphistic features (e.g. one sitemap can extend another one which allows e.g. the implementation of fallback solutions).

Additional Modules

The additional modules cocoon-stringtemplate, cocoon-controller, and cocoon-rest make the development of RESTful webservices simple. Here is the sitemap that invokes a controller:

<?xml version="1.0" encoding="UTF-8"?>
<map:sitemap xmlns:map="http://apache.org/cocoon/sitemap"
  xmlns:servlet="http://apache.org/cocoon/servlet"
  xmlns:controller="http://apache.org/cocoon/controller">
  <map:pipelines>
    <map:pipeline>
      <map:match pattern="videos/{id}">
        <controller:call controller="rest-controller" select="VideoController">
          <map:parameter name="id" value="{map:id}" />
        </controller:call>
      </map:match>
    </map:pipeline>
  </map:pipelines>
</map:sitemap>

And here the controller:

@RESTController
public class VideoController implements Get {

    @SitemapParameter
    private String id;

    @RequestParameter
    private String details;

    public RestResponse doGet() throws Exception {
        Map<String, Object> data = new HashMap<String, Object>();
        data.put("video", new Video(this.id));
        data.put("details", this.details);

        return new Page("servlet:/screen/video", data);
    }
}

When this annotated controller class is being executed, the sitemap parameter id and the request parameter details are passed to the controller.

The controller implements the Get interface which makes it reacting on GET requests. Then the controller invokes the pipeline servlet:/screen/video (see the sitemap in the section above) which uses StringTemplate to render the Video object to XML.