Jetspeed Groovy Portlet with Header Phase Support Guide

Jetspeed-2 provides an interface for a portlet to be able to support the pre-286 header phase. If you want your portlet to support this, just use GroovyPortletHeaderPhaseSupport class instead of GroovyPortlet, and implement SupportsHeaderPhase interface.

1. The Portlet Class supporting header phase

Create the file HelloGroovyHeaderSupport.groovy in a directory called groovy-simplest/WEB-INF/classes: 

import javax.portlet.GenericPortlet;
import javax.portlet.PortletContext;
import javax.portlet.PortletRequestDispatcher;
import javax.portlet.RenderRequest;
import javax.portlet.RenderResponse;
import javax.portlet.ActionRequest;
import javax.portlet.ActionResponse;
import javax.portlet.PortletPreferences;
import javax.portlet.ValidatorException;

import org.apache.jetspeed.headerresource.HeaderResource;
import org.apache.jetspeed.portlet.PortletHeaderRequest;
import org.apache.jetspeed.portlet.PortletHeaderResponse;
import org.apache.jetspeed.portlet.SupportsHeaderPhase;

public class HelloGroovyHeaderSupport extends GenericPortlet implements SupportsHeaderPhase
{
    public void doHeader(PortletHeaderRequest request, PortletHeaderResponse response)
    {
        // use header resource component to ensure header logic is included only once
        HeaderResource headerResource = response.getHeaderResource();
        headerResource.dojoEnable();
        
        headerResource.dojoAddCoreLibraryRequire( "dojo.lang.*" );
        headerResource.dojoAddCoreLibraryRequire( "dojo.event.*" );
        headerResource.dojoAddCoreLibraryRequire( "dojo.io.*" );
        headerResource.dojoAddCoreLibraryRequire( "dojo.widget.*" );
        headerResource.dojoAddCoreLibraryRequire( "dojo.widget.Button" );
     }
    
    public void doView(RenderRequest request, RenderResponse response)
    {
        response.setContentType("text/html");
        
        // Let's put a dojo widget button for simplicity here.
        response.getWriter().println """
            <button widgetId="helloGroovyButton" dojoType="Button" onclick="alert('Hello, Groovy');">
            Say Hello
            </button>
        """
    }
    
}
For simplicity, in the above example, the doView() method just writes a simple HTML fragment to show DOJO button widget.

2. The portlet.xml

<?xml version="1.0" encoding="UTF-8"?>
<portlet-app id="velocitysimplest" version="1.0">
  <portlet id="HelloGroovyHeaderSupport">
    <portlet-name>HelloGroovyHeaderSupport</portlet-name>
    <display-name>Hello Groovy with Header Support Display Name</display-name>
     <portlet-class>org.apache.portals.bridges.groovy.GroovyPortletHeaderPhaseSupport</portlet-class>
    <init-param>
      <name>script-source</name>
      <!-- Note: You can set script source in three ways.
                 The first is to use relative path uri,
                 the second is to use file: url,
                 and the last is to classpath: uri -->
      <!--
      <value>/WEB-INF/groovy/HelloGroovy.groovy</value>
      <value>file:/C:/Program Files/Apache Software Foundation/Tomcat 5.5/webapps/demo/WEB-INF/groovy/HelloGroovy.groovy</value>
      -->
      <value>classpath:HelloGroovyHeaderSupport.groovy</value>
    </init-param>
    <!-- If auto-refresh is true, then a modification of script source applies instantly. -->
    <init-param>
      <name>auto-refresh</name>
      <value>true</value>
    </init-param>
    <supports>
      <mime-type>text/html</mime-type>
      <portlet-mode>VIEW</portlet-mode>
    </supports>
    <supported-locale>en</supported-locale>
    <portlet-info>
      <title>Hello Groovy with Header Support Title</title>
      <short-title>Hello Groovy with Header Support Short Title</short-title>
    </portlet-info>
  </portlet>
</portlet-app>
The <portlet-class> was replaced with 'org.apache.portals.bridges.groovy.GroovyPortletHeaderPhaseSupport' instead of 'org.apache.portals.bridges.groovy.GroovyPortlet' to support header phase.