Datasheet

❑ The portlet session

❑ The window state

❑ The portlet preferences object

❑ The portal context

To change the portlet mode or window state, you call the appropriate method on the

ActionResponse

object. The change becomes evident when the render method is called subsequent to the end of process-

ing in the

processAction method. You can also pass render parameters using the ActionResponse

object.

RenderRequest

RenderRequests generate a fragment from the portlet’s current state. The RenderRequest object pro-

vides access to the following:

❑ The render request parameters

❑ The portlet mode

❑ The portlet session

❑ The window state

❑ The portlet preferences object

There is also an accompanying

RenderResponse method, which provides the vehicle needed to render

content. You can call

getOutputStream or getWriter as you do in a servlet, or you can dispatch the

content generation to a servlet or JSP. There is more detail on this technique later in the chapter, in the

section “Calling JSPs and Servlets.”

GenericPortlet

The GenericPortlet class is an abstract implementation of the Portlet interface. This is the most

common way most users will write portlets — by extending this class. The

GenericPortlet class

extends the

render method by setting the portlet title, and then calling its own doDispatch method,

which in turn, determines the mode of the Portlet, and calls its appropriate method:

doEdit for EDIT,

doView for VIEW, and so on. There is more discussion on portlet modes later. The following code

describes a class that extends

GenericPortlet:

package org.opensourceportals.samples;

import java.io.IOException;

import javax.portlet.ActionRequest;

import javax.portlet.ActionResponse;

The request and response objects are not thread-safe. This means that a developer

should avoid sharing references to them with other threads of execution. Most

developers will not run into this problem, but remember this tidbit next time you

decide to try something unconventional.

The Java Portlet API (JSR 168)

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