Introduction to JSR 286/ Portlet Specification 2.0

Introduction:

JSR 286 is advanced portlet specification and it was added new features to JSR 168.

We can also call Portlet Specification 2.0. Java Community People was founf some of the limitations in JSR 168 and they are added new specifications to JSR 168 then they released as JSR 286 standards.

We already know JSR 168 standard and Portlet Specification 1.0

Introductionto JSR 168/Portlet Specification 1.0

In JSR 168 covers the basic portlet technology need and its specification later Java Community People was added more features and specification in JSR 286.

The following are important Specification and Features

• Inter Portlet Communication
• Another State in Lifecycle
• Ajax Support
• Serving Resources
• Portlet Filter and Listeners
• Support Many Web Application Frame works in Portal Container
• Improve Cache Mechanism
• Support for WSRP 2.0

Inter Portlet Communication

The important feature in JSR 286 is Inter portlet communication. Inter portlet communication is mechanism to send or receive data between two portlets.

We can achieve IPC with different ways in portlets and we can make communication between portlet which are in same page or other pages too. We will use different ways based on our requirement.

In JSR 168 IPC works between portlets which are in same page using Portlet Session Mechanism.

In JSR 286 they made communication between portlet which are in different pages using other mechanism

The following are new IPC mechanism added in JSR 286

1. Events
2. Public Render Parameters

Events:

Event based mechanism way to communicate between portlet which are in same or in other page too.

Here one portlet will send the event and other portlet will listen the event. Here another method added in lifecycle so that it send or publish the events and when page render respective listener portlets receive the dada or events. Here before portlet execute render phase it can send events to other portlets

Public Render Parameters

Public render parameters are another way in IPC. We will use some public render parameters to each portlet so that it will carry the data between portlet and it will available to other portlets.

We will define some public render parameter such a way it will available to other portlet to get the data from that.

Another State in Portlet Lifecycle

New lifecycle phase added in portlet lifecycle. In JSR 168 the state of transition change from Action Phase to Direct Render Phase no more states in between that.

In JSR 286 to implement IPC they will add another Lifecycle state that is called Events Phase.

Before transition from Action Phase to Render Phase portlet can send events to other portlet in Events phase. So that another  lifecycle phase was added for portlet so that it will send some events to other portlet.

 Ajax Support

JSR 286 support Ajax mechanism to communicate with server. This is one of the good features. Generally if any portlet is have in action page other portlet need to render the portlet within the page.

With the help of Ajax we can avoid render all portlets in page. We simply send Ajax call from portlet so that we can communicate with server then get the response.

Serving Resources

In JSR 168 portlet specification will render only HTML content in render phase it can’t render some resources like pdf, images and other content type.

In JSR 286 was added another feature called serving resources with help of this we can serve the images, pdf and other content types to client.

In the portlet interface they added new method called serveResource(----)  method so that It will serve the other content types to client. This method also used specially for Ajax call in portlet, to call this method we will use different URL i.e. serve recourse URL.

Generally in the portlet transition state will always change from Action Phase to Render Phase when we perform actions.

But when we call serve Resource phase it will directly serve the content and it won’t go to render phase.

Portlet Filter and Listeners

We can portlet related filters and Listeners in portlet portlet.xml file. This will add advantage to perform some events or some actions before portlet is rendered.

Support Many Web Application Frame works in Portal Container

Generally Portal specification is different and we will use portlet container to manage portlets and its lifecycle. But we have many elegant web application frameworks.

In JSR 286 support other web frame works to run in portlet container so that developer can develop portlet in any web application frame work and run in the portlet container with help of small changes. It will support JSF, Struts, Spring, Vaadin and other MVC bases frameworks.

Support for WSRP 2.0

The Web Services for Remote Portlets specification defines a web service interface for accessing and interacting with interactive presentation-oriented web services.

This will help us access portlet from remote location other portals. We need to deploy portlet in portal we simply use this protocol we can access other portlet which are in other portlet container.

WSRP 2.0

Author

Meera Prince

Liferay Top Contributor Award Winner

http://www.liferaysavvy.com

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Liferay Client Side Inter Portlet Communication Using Ajax

Objective:

Achieve inter portlet communication from client side using Ajax and Liferay Java Script.

Introduction:

Inter portlet communication is way of exchange the data between portlets in the page or portlets which reside in the other pages.

In liferay we have different ways we can achieve this one of the way is client side inter portlet communication.

Environment:

Liferay 6.2 +Tomcat 7.x+MySQL 5.1

Note:

The code will work for portal 6.2 version you can try for 6.1 too.

Download Client Side IPC portlet from following location

You can find source and war file

https://sourceforge.net/projects/meeralferay/files/LiferayClientSideIPCPortlet/

Portlet Screen:

Procedure for deploy portlet:

You can use war file and directly place in your portal deploy folder and test or you can also use source to deploy portlet.

Once portlet is deployed successfully you can see the portlet in sample category names as Sender Portlet and Receiver Portlet.

Usage Of Portlets:

Drag and Drop two portlet in same page and enter email address in sender portlet then click on send button as soon as you click you can see user details in receiver portlet.

Client Side Inter Portlet Communication (IPC):

Client Side Inter Portlet Communication is one of the ways in IPC   this can apply the portlet which reside in same page. Because Client side IPC will uses java script to communicate that’s why all portlet which participated in IPC need to be in same page.

Liferay already have some java script library to implement client side IPC in portlet 

development.

The following diagram show you the IPC among Portlets

Here we have two types of portlets

Sender Portlet

Receiver Portlet

Sender Portlet:

Sender portlet will fire or trigger the event means it will initiate the sending message to other portlet.

Receiver Portlet

Receiver portlet is ready to take/listen the event from sender portlet as soon as sender portlet send the message then receiver portlet reactive the messages. Here one or more receiver portlet can be for one sender portlet.

The thing is we need to bind the receiver portlet with sender event. So that it can be listen the event as soon as sender sends the message.

Note:

All portlet which participate in client side IPC should be in same page and here page refresh will not be happened.

Assumption:

Assume we have sender and receiver portlet in page and sender will get some user data from server and the data will be pass to receiver portlet.

Sender portlet get the data from server it will use the Ajax call and once it will get the data then the data will be sending to receiver portlet using Client Side IPC with help of liferay java script implementation methods.

Register event in sender portlet as follows

Java script syntax  Liferay.fire('eventName',{                 param1:paramValue1,                 param2:paramValue2 }); Example code as follows in sender portlet view.jsp Liferay.fire('getUserData',{               name: Meera Prince });

Receive the event from Sender Portlet in receiver portlet as Follows

Java script syntax Liferay.on('eventName',function(event) { // write code to get the veluese that sent by sender portlet }); Example code as follows in receiver portlet view.jsp Liferay.on('getUserData',function(event) {  alert('User Name:'+ event.name) });

Implementation In development

The following are the steps to implement

1. Create Two Liferay MVC portlets
2. Make it <requires-namespaced-parameters/>   tag value to false in portlets
3. Register Event in Sender Portlet
4. Receive Event in Receive portlet

Note:

This is Client Side IPC events mechanism using java script and the portlet all are in same page.

Create Two Liferay MVC portlets

Create two Liferay MVC portlet from Liferay IDE with eclipse environment and decide Sender and Receiver portlets.

The following is more information to set up Liferay Development Environment

http://www.liferaysavvy.com/2013/12/liferay-62-portal-development.html

Make it <requires-namespaced-parameters/>   tag value to false in portlets

In liferay-portlet.xml file we need to make <requires-namespaced-parameters/>   tag value to false so that we can pass data in request using Ajax call.

This we need to make it false in spring portlet and when we use ajax as well.

If we make it false then only we can pass data to server using Ajax call.

The following is example for liferat-portlet.xml file as follows

<portlet> <portlet-name>sender</portlet-name> <icon>/icon.png</icon> <instanceable>false</instanceable> <requires-namespaced-parameters>false</requires-namespaced-parameters> <header-portlet-css>/css/main.css</header-portlet-css> <footer-portlet-javascript>/js/main.js</footer-portlet-javascript> <css-class-wrapper>sender-portlet</css-class-wrapper> </portlet>

Which portlet need Ajax interaction then we need to make it false to that portlet.

Register Event in Sender Portlet

Now we need register required even in Sender portlet so that it will send events to receiver portlets. This is complete java script implementation and we will use Liferay java script implementation.

Here we will get user information from server using jQuery Ajax call and once we get user data then we are sending to receiver portlet  using liferay java script implementation method i.e. Liferay.fire(----)

The following is example code in Sender Portlet view.jsp page

<%@page import="com.liferay.portal.theme.ThemeDisplay"%> <%@ taglib uri="http://java.sun.com/portlet" prefix="portlet"%> <%@ taglib uri="http://liferay.com/tld/aui" prefix="aui" %> <%@ taglib uri="http://liferay.com/tld/theme" prefix="liferay-theme" %> <%@ page import="com.liferay.portal.kernel.portlet.LiferayWindowState" %> <script src="http://ajax.googleapis.com/ajax/libs/jquery/1.10.2/jquery.min.js"></script> <portlet:defineObjects /> <liferay-theme:defineObjects /> <portlet:resourceURL var="getUserData"> </portlet:resourceURL> <script> $(document).on('ready',function(){ jQuery('#<portlet:namespace/>getUserByEmail').click(function(event) { var emailAddessValue = jQuery('#<portlet:namespace/>emailAddess').val();   $.ajax({ url:'<%=getUserData%>', dataType: "json", data:{emailAddess:emailAddessValue, companyId:'<%=themeDisplay.getCompanyId()%>' }, type: "get", success: function(data){ Liferay.fire('getUserData', {userData:data}); }, beforeSend: function(){ //before send this method will be called }, complete: function(){ //after completed request then this method will be called. }, error: function(){ $('#userContent').html('<span style="color:red">Connection problems</span>'); } }); }); }); </script> <aui:form method="POST" action="<%=getUserData%>" > <aui:input type="text" name="emailAddess"   id="emailAddess" label="Email Address"/> <aui:button type="button" name="getUserByEmail" value="Send" id="getUserByEmail" /> </aui:form>

Receive Event in Receive portlet

Now we need to receive the even in receiver portlet. We already know sender send the message or event now we need to catch the message using Liferay.on(---) method.

Note:

We can have multiple receiver portlet for one sender portlet.

The following is complete code in receiver portlet view.jsp page

<%@ taglib uri="http://java.sun.com/portlet" prefix="portlet"%> <%@ taglib uri="http://liferay.com/tld/aui" prefix="aui" %> <%@ taglib uri="http://liferay.com/tld/theme" prefix="liferay-theme" %> <portlet:defineObjects /> <style> #userData td{ font-weight: bold; width:200px; border: 1px solid gary; } </style> <script> Liferay.on( 'getUserData',function(event) { jQuery('#userInformation').empty(); jQuery('#errorInformation').empty(); if(event.userData.error!=null){             jQuery('#errorInformation').html(event.userData.error); }else{ var htmlString="<table id='userData'>"+ "<tr><td>User Id</td><td>"+event.userData.userId+"</td></tr>"+ "<tr><td>First Name</td><td>"+event.userData.firstName+"</td></tr>"+ "<tr><td>Last Name</td><td>"+event.userData.lastName+"</td></tr>"+ "<tr><td>Email Address</td><td>"+event.userData.emailAddress+"</td></tr>"+ "</table>"; jQuery('#userInformation').html(htmlString); } }); </script> <div id="userInformation"></div> <div id="errorInformation" style="color:red;font-weight:bold;"></div>

Important points:

• Inter Portlet Communication (IPC) can be achieved in different ways and client side IPC is one of the way.
• Client Side IPC is pure java script implementation so that It apply only the portlet which are in same page.
• Liferay implemented some java script methods to implement Client Side IPC.
• We used Ajax call to get data from server one we get the data we populated in other portlet using Client Side IPC.

Author

Meera Prince

Liferay Top Contributor Award Winner

http://www.liferaysavvy.com

Read More