Create your own portlet service

 

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  1. Define the interface
  2. Writing the service implementation
  3. Making the service accessible for IBM portlets
  4. Registering the service

The service provider interfaces can be used to write portlet services for IBM portlets as well as for Standard portlets. The IBM Portlet API is being deprecated for WebSphere Portal V6.0 but is still supported. No new functionality will be added and IBM recommends that you use the Standard portlet API. For backward-compatibility, the service provider interfaces from the org.apache.jetspeed.portlet.service.spi packages are supported. For writing new portlets services, however, you should use only the service provider interfaces described in this text.

 

Define the interface

This step is not required to implement the service against an existing interface. Defining a portlet service interface requires the same careful considerations as defining any public API interface. A portlet service interface must extend the PortletService interface defined in the com.ibm.portal.portlet.service package. The following is an example interface for the HelloWorldService. 

package sample.portletservice;

import java.io.IOException;
import javax.portlet.RenderRequest;
import javax.portlet.RenderResponse;
import com.ibm.portal.portlet.service.PortletService;

public interface HelloService extends PortletService {
    /** print a nice greeting */
    public void sayHello(RenderRequest request, RenderResponse response) 
           throws IOException;
}

 

Writing the service implementation

The service implementation must implement the PortletServiceProvider interface of the com.ibm.portal.portlet.service.spi package to be able to make use of the portlet service life cycle methods in addition to the service interface. The PortletServiceConfig parameter of the init() method allows you, for example, to access the configuration of the service (see Registering the service for more information). 

package sample.portletservice;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.prefs.Preferences;

import javax.portlet.RenderRequest;
import javax.portlet.RenderResponse;

import com.ibm.portal.portlet.service.spi.c;
 
public class HelloServiceImpl implements HelloService, PortletServiceProvider 
{
    
    private String message;
        
    // called by the portal when the service is initialized        
    public void init(Preferences servicePreferences) 
    {
        
        // read the message from the configuration, default is "Hello"
        message = servicePreferences.get("message", "Hello");
    }
        
    public void sayHello(RenderRequest request, RenderResponse response) 
                throws IOException 
    {
        String user = request.getRemoteUser();
        if (user == null)
            // no user logged in             user = "Stranger";
        
        PrintWriter out = response.getWriter();
        out.print(message);
        out.print(", ");
        out.print(user);            
    }

}

 

Making the service accessible for IBM portlets

This step is optional. If you want the portlet service to be available for IBM portlets, we need to create an additional service interface that extends org.apache.jetspeed.portlet.service.PortletService and provides the same functionality. 

package sample.portletservice;

import java.io.IOException;
import org.apache.jetspeed.portlet.PortletRequest;
import org.apache.jetspeed.portlet.PortletResponse;
import org.apache.jetspeed.portlet.service.PortletService;

public interface HelloServiceIBM extends PortletService 
{

    /** print a nice greeting */
    public void sayHello(PortletRequest request, PortletResponse response) throws IOException;

}

We can have a single implementation that is registered for both interfaces and implements both. If the service methods take arguments that are classes or interfaces from the portlet API, the method signatures are different for the two service interfaces. We can still use a common implementation for both interfaces by using the APIConverterFactory class of the com.ibm.portal.portlet.apiconvert package. This class includes methods that wrap objects from the IBM portlet API, such as the PortletRequest and PortletSession, and implement the corresponding standard portlet API objects on the service side, so that we can re-use the service implementation for standard portlets. 

package sample.portletservice;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.prefs.Preferences;

import javax.portlet.RenderRequest;
import javax.portlet.RenderResponse;

import org.apache.jetspeed.portlet.PortletRequest;
import org.apache.jetspeed.portlet.PortletResponse;

import com.ibm.portal.portlet.apiconvert.APIConverterFactory;
import com.ibm.portal.portlet.service.spi.PortletServiceProvider;
 
public class HelloServiceImpl2 implements HelloService, HelloServiceIBM, PortletServiceProvider 
{
    
    private String message;
        
    // called by the portal when the service is initialized        
    public void init(Preferences servicePreferences) 
    {
        
        // read the message from the configuration, default is "Hello"
        message = servicePreferences.get("message", "Hello");
    }
        
    public void sayHello(RenderRequest request, RenderResponse response) 
                throws IOException 
    {
        String user = request.getRemoteUser();
        if (user == null)
            // no user logged in             user = "Stranger";
        
        PrintWriter out = response.getWriter();
        out.print(message);
        out.print(", ");
        out.print(user);            
    }
    
    public void sayHello(PortletRequest request, PortletResponse response) 
                throws IOException 
    {
        sayHello (APIConverterFactory.getInstance().getRenderRequest(request),
            APIConverterFactory.getInstance().getRenderResponse(response));
    }

}

 

Registering the service

  1. Put all service interface and implementation classes into a JAR file.

  2. Place the JAR file in the portal_server_root/shared/app directory.

  3. Register the new portlet service with the PortletServiceRegistryService service in the WAS administrative console. For more information on registering services, see Setting configuration properties.

  4. Restart WebSphere Portal to activate the new settings.

In the following example, HelloService is the name of the portlet service, HelloServiceIBM is the name of the interface for IBM portlets, and the message configuration parameter is set with the value Greetings.

Currently the colon (:) is not supported. Avoid using these in the code. 

jndi:sample.portletservice.HelloService = 
                      sample.portletservice.HelloServiceImpl2
sample.portletservice.HelloServiceIBM = 
                      sample.portletservice.HelloServiceImpl2
sample.portletservice.HelloServiceImpl2.message = Greetings

Tip: To check whether the service has been registered successfully, use the application server dumpNamespace tool. The following command, executed from the was_profile_root/bin directory, will list all portlet service entries in JNDI: 

    dumpNamespace -port bootstrap_port -root server -startAt portletservice

Using the application server's administrative console, we can find the bootstrap port of the portal server in the "End Points" section of the settings for the server "WebSphere_Portal".

 

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