Developing Portlets with GWT

How to write a portlet with the aim of GWT.

Pre-development Actions

Modifying Tomcat

1. Replace $CATALINA_HOME/webapps/gridsphere/WEB-INF/CustomPortal/layouts/TemplateLayout.xml with the corresponding one found here.
2. Include gwt.js and script.html files found here in $CATALINA_HOME/webapps/gridsphere/html directory.

Modifying Gridpshere Home

If you want you can also apply the respective changes to gridsphere's home directory. This can be useful if, for some reason, you want to redeploy gridsphere.

Installing GWT

1. Download the latest version of GWT from here.
2. Uzip the file.
3. Set environmntal variable: GWT_HOME=<the name of the folder where you unpacked gwt files>

Creating a gwt-portlet

Creating a gwt project

In order to create a gwt project, you must execute:

>cd $GRIDPSHERE_HOME/projects
>mkdir <module_dir_name>
>cd <module_dir_name>
>$GWT_HOME/projectCreator -eclipse MyProject
>$GWT_HOME/applicationCreator -eclipse MyProject org.diligentproject.<whatever>.client.<ModuleName>

Now you can develop your gwt project as you wish by using eclipse!
FYI, there is a toolkit for eclipse that provides developers with a GUI so as to design their gwt modules.
However, it's not free. If you wish to see its demos, click here.

You can find useful information about the Google Web Toolkit on its official site: http://code.google.com/webtoolkit/

Creating a jsr 168 portlet

In oder to create an empty portlet project, you must execute:

>cd $GRIDPSHERE_HOME/
>ant new-project
    * insert: <Portlet's Title>
    * insert: <module_dir_name>  --- This must be the same as in gwt project
    * insert: jsr

Now, if you refresh the eclipse project, you can see that the "portlet-files" are generated.

Creating the portlet class

• Create a class named: org.diligentproject.<whatever>.portlets.<portletClassName>
• Add the following content to the class:

	// 	JSP folder name
	public static final String JSP_FOLDER = "/jsp";
	//	 JSP file name to be rendered on the view mode

	public static final String VIEW_JSP = JSP_FOLDER + "/<a_name_for_the_jsp_page>.jsp";
	
	
    public void doView(RenderRequest request, RenderResponse response) throws PortletException, IOException{
		// ------------------------------------------------------------
		// Note: The portlet is just diplaying a JSP for the AJAX Lab.
		// It does absolutely nothing else.
		// ------------------------------------------------------------
    	
    	// Set the MIME type for the render response
		//response.setContentType(request.getResponseContentType());
    	
		// Invoke the JSP to render
    	
    	
		PortletRequestDispatcher rd = getPortletContext().getRequestDispatcher(VIEW_JSP);
		rd.include(request,response);            
    }

Creating the jsp page

• Create a file in the webapp/jsp directory named: <a_name_for_the_jsp_page>.jsp.

• In this file you place the following content:

<%@ page contentType="text/html" %>
<%@taglib uri="http://java.sun.com/portlet" prefix="portlet" %>

<!--                                           -->
<!-- The module reference below is the link    -->
<!-- between html and your Web Toolkit module  -->		
<!--                                           -->
<meta name='gwt:module' content='org.diligentproject.<whatever>.client.<ModuleName>'>
	
<!--                                            -->
<!-- This script is required bootstrap stuff.   -->
<!-- You can put it in the HEAD, but startup    -->
<!-- is slightly faster if you include it here. -->
<!--                                            -->

<div id="<a unique name for the DIV">
</div>

I should mention here that the org.diligentproject.<whatever>.client.<ModuleName> is the one you defined when you created the gwt application.
Additionally, the id for the div is good to be a name related to the portlet-name.