Abstract Portlet class

 

The abstract Portlet class extends HttpServlet. 

...   +--javax.servlet.http.HttpServlet
         |
         +--org.apache.jetspeed.portlet.Portlet
               |
               +--org.apache.jetspeed.portlet.PortletAdapter
                    | 
                    +--com.myCompany.myApplication.myPortlet

Unlike servlets, portlets cannot send redirects or errors to browsers directly, forward requests, or write arbitrary markup to the output stream. The portlet container relies on the J2EE architecture implemented by WebSphere Application Server. As a result, portlets are packaged similar to J2EE Web applications and are deployed like servlets.

Generally, portlets are administered more dynamically than servlets. The following updates can be applied without having to start and restart the portal server:

  • Portlet applications consisting of several portlets can be installed and removed using the portal administration user interface.

  • The settings of a portlet can be changed by an administrator with appropriate access rights

  • Portlets can be created and deleted dynamically by administration portlets. For example, the clipping portlet can be used to create new portlet instances whenever an administrator creates a new clipping.

The portlet container relies on the J2EE architecture implemented by WebSphere Application Server. As a result, portlets are packaged in WAR files similar to J2EE Web applications and are deployed like servlets. Like other servlets, a portlet is defined to the appserver using the servlet deployment descriptor (web.xml). This file defines the portlet's class file and read-only initialization parameters.

The initialization parameters are set by the portlet developer and can be read by the portlet using the PortletConfig object. The servlet deployment descriptor can contain multiple Web applications, each defined by the <servlet> element. In addition, each servlet definition can point to the same portlet class file, thus creating different PortletConfig objects with different initialization parameters for each portlet class instance.

 

See also

Home |

 

WebSphere is a trademark of the IBM Corporation in the United States, other countries, or both.

 

IBM is a trademark of the IBM Corporation in the United States, other countries, or both.