Interportlet communication in different war files (portlet applications) – Part 1

Inter-portlet communication between multiple portlets in different portlet applications has been made easy with JSR 286 portlet API. It has brought a new revolution in portlet development. In JSR 168 a.k.a portlet specification 1.0, inter-portlet communication between portlets in different war files was not possible. The only way to achieve it was through IBM URL Generation classes. But JSR 286 gives you more flexibility to achieve this functionality.

There are 2 ways to achieve interportlet communication between portlets in different portlet applications.

1. By using public render parameters of JSR 286 portlet development API.

2. By using processEvent() method.

I will be discussing the first method in this article. The second approach will be discussed in the next article. In the first method you can pass only string params while the second one gives you flexibility to pass complex collection objects. I have created sample applications for both approaches.

The sample application uses IBM websphere portal 7, JSR 286 portlet development API, Annotation based Spring MVC Portlet framework 3.1. There are 2 portlets applications PortletApplication 1 which has TestPortlet1 and PortletApplication2 which has TestPortlet2.

Listing 1: TestPortlet1Controller.java

@Controller

@RequestMapping("VIEW")

public class TestPortlet1Controller{

@RenderMapping

protected ModelAndView defaultHandleRenderRequest(RenderRequest request,RenderResponse response) throws Exception {

ModelAndView mav = new ModelAndView("list1");

return mav;

}

@ActionMapping(params = "action=insert")

public void insert(ActionRequest request, ActionResponse response) {

String name = request.getParameter("name");

response.setRenderParameter("name", name);

}

}

Listing 1.1 TestPortlet1.xml:

<portlet>

…

<supported-public-render-parameter>name</supported-public-render-parameter>

…

<public-render-parameter>

<identifier>name</identifier>

<qname xmlns:customns="http://testportlet1_params/">customns:name</qname>

</public-render-parameter>

</portlet>

Listing 2: TestPortlet2Controller.java

@Controller

@RequestMapping("VIEW")

public class TestPortlet2Controller{

@RenderMapping

protected ModelAndView defaultHandleRenderRequest(RenderRequest request,

RenderResponse response) throws Exception {

ModelAndView mav = new ModelAndView("list2");

String name = request.getParameter("name");

System.out.println("TestPortlet2Controller========"+name);

mav.addObject("name",name);

return mav;

}

}

Listing 2.1 TestPortlet2.xml:

<portlet>

…

<supported-public-render-parameter>name</supported-public-render-parameter>

…

<public-render-parameter>

<identifier>name</identifier>

<qname xmlns:customns="http://testportlet1_params/">customns:name</qname>

</public-render-parameter>

</portlet>