Access portlet services

To use the portlet service, you retrieve a service object from the home, cast it to the service-specific interface and invoke service methods.

See Portlet services for a general overview of portlet services. The following example shows how a standard portlet can retrieve and use a sample portlet service. The service implementation and deployment is explained in Create our own portlet service.

Accessing a portlet service requires a JNDI lookup for a PortletServiceHome. As this is may be a rather expensive operation, we should do it in the init() method of the portlet and store the returned object in an instance variable:

   import javax.portlet.*;
   import com.ibm.portal.portlet.service.*;
    private PortletServiceHome helloServiceHome = null;
   ...
       public void init(PortletConfig config)     {
      javax.naming.Context ctx = new javax.naming.InitialContext();
      try {
          Object home = ctx.lookup("portletservice/sample.portletservice.HelloService");
          if (home != null)       helloServiceHome = (PortletServiceHome) home;
      } catch(javax.naming.NameNotFoundException ex) {
      // we can do without the service, if it is not available              config.getPortletContext().log("No hello service available");
      }
   }

The example is written to gracefully handle a situation where the service is not available because the service is optional for the functionality of the portlet. If possible, we should write the portlets so they are portable across portal installations, whether they support a given portlet service or not. Such portlets can still run on portals that have not support for portlet services at all and do not even provide the IBM-specifc PortletServiceHome class, because this class is only loaded when the service is actually registered in JNDI.

To use the portlet service, you retrieve a service object from the home, cast it to the service-specific interface and invoke service methods:

   public void doView(RenderRequest request, RenderResponse response)
   {
      if (helloServiceHome != null)
      {
         HelloService service = (HelloService) helloServiceHome.getPortletService(HelloService.class);
         service.sayHello(request, response);
      }
          //... do other stuff
   }

Note that, while it is good practice to store the PortletServiceHome object in an instance variable, we must not store the actual service object, because references to service objects may not be held for longer than a single request.

Related information

• Portlet services
• Create our own portlet service

Parent Portlet services