Liferay startup failed error.

Although I was able to run Liferay 5.2.3 on my windows vista machine for a long time, suddenly it stop working because when I click startup.bat it gives the following errors and startup failed.

SEVERE: Context [] startup failed due to previous errors
20-May-2010 14:25:10 org.apache.catalina.loader.WebappClassLoader loadClass
INFO: Illegal access: this web application instance has been stopped already. Could not load org.apache.log4j.spi.LocationInfo. The eventual following stack trace is caused by an error thrown for debugging purposes as well as to attempt to terminate the thread which caused the illegal access, and has no functional impact.
java.lang.IllegalStateException
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1273)
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1233)
at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:319)
at org.apache.log4j.spi.LoggingEvent.getLocationInformation(LoggingEvent.java:247)
at org.apache.log4j.helpers.PatternParser$LocationPatternConverter.convert(PatternParser.java:483)
at org.apache.log4j.helpers.PatternConverter.format(PatternConverter.java:65)
at org.apache.log4j.PatternLayout.format(PatternLayout.java:502)
at org.apache.log4j.WriterAppender.subAppend(WriterAppender.java:302)
at org.apache.log4j.WriterAppender.append(WriterAppender.java:160)
at org.apache.log4j.AppenderSkeleton.doAppend(AppenderSkeleton.java:251)
at org.apache.log4j.helpers.AppenderAttachableImpl.appendLoopOnAppenders
(AppenderAttachableImpl.java:66)
at org.apache.log4j.Category.callAppenders(Category.java:206)
at org.apache.log4j.Category.forcedLog(Category.java:391)
at org.apache.log4j.Category.log(Category.java:856)
at com.liferay.portal.log.Log4jLogImpl.info(Log4jLogImpl.java:80)
at com.liferay.portal.kernel.log.LogWrapper.info(LogWrapper.java:124)
at com.liferay.portal.kernel.deploy.hot.HotDeployEvent.initDependentServletContextNames
(HotDeployEvent.java:108)
at com.liferay.portal.kernel.deploy.hot.HotDeployEvent.(HotDeployEvent.java:57)
at com.liferay.portal.kernel.servlet.HookContextListener.contextInitialized(HookContextListener.java:47)
at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:3843)
at org.apache.catalina.core.StandardContext.start(StandardContext.java:4342)
at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:791)
at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:771)
at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:525)
at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.java:926)
at org.apache.catalina.startup.HostConfig.deployDirectories(HostConfig.java:889)
at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:492)
at org.apache.catalina.startup.HostConfig.start(HostConfig.java:1149)
at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java:311)
at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:117)
at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1053)
at org.apache.catalina.core.StandardHost.start(StandardHost.java:719)
at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1045)
at org.apache.catalina.core.StandardEngine.start(StandardEngine.java:443)
at org.apache.catalina.core.StandardService.start(StandardService.java:516)
at org.apache.catalina.core.StandardServer.start(StandardServer.java:710)
at org.apache.catalina.startup.Catalina.start(Catalina.java:578)

But at the end I was able to run it with out any problem after removing the following from the from the bin/setenv.bat.

if not "%JAVA_HOME%" == "" (
set JAVA_HOME=
)

Although it is working well now, I'm wondering why this has happened suddenly...................!

Create a JSR 168 compatible JIRA portlet for Liferay.

Although Liferay web portal has a JIRA portlet which comes under World of Liferay (WOL), it is not a generic portlet which can be configured to work with any JIRA installation. It is written in a way which can display the issue summery from the Liferay organisation's JIRA application. This portlet is tightly bundled with several other portlets which are also in the WOL category. Also the code of the portlet was scattered everywhere, which made it is very difficult to understand. So extending the functionalities and maintaining the code was extremely hard.

But I had a requirement of creating a portlet which can be communicate with any JIRA installation. So I implemented a JSR 168 compatible portlet for JIRA. You can refer to this for get an idea about how I implemented that. Following diagrams shows the JIRA portlet.

• This is the first view of the portlet when you add that to the portal page.
  

• After user click on the link above, he can see the following edit mode of the portlet. Here user needs to enter the URL of the JIRA application and the Login name of the JIRA.
  
• 
• After the required values are entered these values are stored as preferences to the portlet and it will display the success message as follows.
• Finally after the user Return to the full page, it will display the issue counts as follows.

You can download the complete source code of it from here and feel free to use it and give comments.

Creating Liferay Themes

Liferay Themes customize the overall look and feel of Liferay and were introduced in version 3.5 of the portal. There are two ways to develop themes for Liferay. They are using,

• Liferay Plugins SDK
• Using Portal Pack on NetBeans IDE With Theme Plugin Support

Here I explained how to develop themes using Portal Pack on NetBeans. Before you start, install the Portal Pack 3.0.2 plugins on NetBeans IDE 6.5, 6.5.x, or 6.7 version. You can download the latest Portal Pack plugin from here.

You can refer this to Install the portal pack plugins and add the Liferay server to NetBeans.

Create a Web Application That Uses Liferay Portal Server as the Target Runtime:

• Choose New Project from the File menu.
• By default, Java Web and Web Application are selected from Categories and Projects respectively.
• Click Next.
• Type a name for the project, and click Next.
• In this example, name the project CustomTheme.
• Select WLiferay Portal Server5.1.x/5.2.x as the server, and click Next.
• Click Finish.

To Create a Liferay Theme:

• Right-click the project (CustomTheme) and choose New → Other.
• A window appears.
• Choose WebSpace/Liferay Plugins from Categories and Import/Create New Themefrom File Types, and click Next.
• Type a Theme ID and Theme Name. You can also specify a theme folder.
• In this example, use Custom_theme and Custom Theme as the Theme ID and Theme Name respectively. If you are creating more than one theme, it is better to create a Theme Folder as well.
• Click Finish.

Making Changes to the Theme:

• You can change the theme by adding new images to images/common folder and edit the custom.css file.

Deploy the theme:

• To deploy the custom theme, right-click the project and choose Deploy.
• The theme is deployed to the Liferay Server, and you can apply the theme to the Liferay instance on your machine.

Build a .war file of the theme:

• Copy the folder of the theme (Which is in Liferay webapps folder) to a seperate location.
• Using command prompt navigate to that folder location.
• Then enter the following command in the command prompt.

jar -cvf themename.war *

• Then it will create a file called themename.war file and you can use it to deploy in other liferay instances.

References: http://netbeans.org/kb/docs/web/portal-pack-themes.html

Integrate Liferay with CAS server.

Central Authentication Service (CAS) server is a single sign on (SSO) protocol for the web. Its purpose is to permit a user to access multiple applications while providing their credentials (such as userid and password) only once. It also allows web applications to authenticate users without gaining access to a user's security credentials, such as a password.

CAS was conceived and developed by Shawn Bayern of Yale University Technology and Planning. In December 2004, CAS became a project of the Java Architectures Special Interest Group, which is as of 2008 responsible for its maintenance and development. Formerly called "Yale CAS", CAS is now also known as "JA-SIG CAS". In oder to implement SSO with Liferay, I used the CAS server.

Following steps gives all the steps that I followed implemennting SSO in Liferay. I used Liferay (liferay-portal-tomcat-6.0-5.2.3), CAS Server (cas-server-3.3.5-release) and CAS client (cas-client-2.0.11).

Setting up CAS server:

• Download the CAS server from http://www.ja-sig.org/downloads/cas/
  
• Rename the cas-server-3.3.5\modules\cas-server-webapp-3.3.5.war to cas-web.war.
• Drop the cas-web.war file into Tomcat's webapps directroy. (For testing purposes I used the Liferay's tomcat but in a production environment CAS servershould really run on its own tomcat instance.
• Then edit the server.xml file in tomcat and uncomment the SSL section to open up port 8443 as shown below.

Setting up the CAS client:

• Download the CAS client from http://www.ja-sig.org/downloads/cas-clients/
• Place the casclient.jar in cas-client-2.0.11\java\lib to ROOT/web-inf/lib of the Liferay install.

Generate the SSL cert with Java keytool:

• In any directory ( I use my root ) enter the command:

keytool -genkey -alias tomcat -keypass changeit -keyalg RSA

• Answer the questions as shown in the image: (note that your firstname and lastname MUST be hostname of your server and cannot be a IP address; this is very important as an IP address will fail client hostname verification even if it is correct)

• Then enter the command:

keytool -export -alias tomcat -keypass changeit -file %FILE_NAME%

I use server.cert for %FILE_NAME%.

• Finally import the cert into Java's keystore with this command.

keytool -import -alias tomcat -file %FILE_NAME% -keypass changeit -keystore %JAVA_HOME%/jre/lib/security/cacerts

• Startup the CAS server by startup.bat in the bin folder.
• Now you are ready to startup your CAS server. Simply startup Tomcat and access CAS with https://localhost:8443/cas-web/login You should see the CAS login screen and no errors in your catalina logs.
  

Setting up Liferay Portal:

• Remove the sevencogs theme and the sample data by deleting the two sevencogs folders at the liferay-portal-5.2.3\ tomcat-6.0.18\webapps folder and by deleting the lportal.properties and lportal.script files at the liferay-portal-5.2.2\data\hsql folder.
• Now if you run the liferay you should be able to login to portal by
  

E-mail: test@liferay.com
Password: test

• In the webapps/ROOT/WEB-INF/web.xml file add a new filter as shown below(add it as the first filter).
• Then add the filter mapping directly above the first existing filter mapping as shown below.
  • 
• Then add the following to the rest of the auto login filters.(Just after the last existing auto login filter)
• Now Start up the Liferay and Go to sign in.
• It will redirect you you CAS login page.
  
• Then Enter the
  

NetID = test
Password = test

• Then you will returned back to the Liferay home page as logged in user test.
  

Liferay JIRA with my own JIRA installation.

Although I was able to configure the jira portlet to work with my own JIRA installation (You can find all the steps at my previous post) there was a serious issue with that. When I logged in as a valid user to my Running JIRA (on http://localhost:8090) I can create new projects(only if logged in as administrator), and create new issues to any of projects. In JIRA there is a unique ID for each project. (Eg: 10000, 10010 etc) When you create a new project, JIRA will assign an new unused ID for that and that ID is used everywhere within the database in order to identify the project. Project details are stored in jiradb/project table and issue details are stored in jiradb/jiraissue table. You can go to your database and see them if you want.

The problem with World of Liferay -JIRA portlet was it uses some constant project IDs and names in order to display the issue summery to the user. It stores this constants values in JIRAConstants.java interface. The view_jira.jspf file uses these constant IDs when creating the objects for the projects to display. So in order to change this, I had to change this view_jira.jspf completely.

I connected to the database of JIRA (jiradb) and select all the project IDs, their name and keys from the table project. Then I created the Jiraproject objects according to these data. The code is shown in below.

String[] prjIDs = new String[20];
String[] prjNames = new String[20];
String[] prjKeys = new String[20];
int meme =0;

Connection conn = null;
String myurl = "jdbc:mysql://127.0.0.1:3306/";
String mydbName = "jiradb";
String mydriver = "com.mysql.jdbc.Driver";
String myuserName = "root";
String mypassword = "";
try {
Class.forName(mydriver).newInstance();
conn = DriverManager.getConnection(myurl+mydbName,myuserName,mypassword);
Statement s = conn.createStatement ();
ResultSet resultset = s.executeQuery ("SELECT ID, pname, pkey FROM project");

while (resultset.next() )
{
String myID = resultset.getString("ID");
String myName = resultset.getString("pname");
String myKey = resultset.getString("pkey");

prjIDs[meme] = myID;
prjNames[meme] = myName;
prjKeys[meme] = myKey;
meme = meme+1;
}
} catch (Exception e) {
e.printStackTrace();
}
for (int i = 0; i <>
Object[] jiraProject = new Object[] {Integer.parseInt(prjIDs[i]), prjKeys[i], prjNames[i]};
int projectId = (Integer)jiraProject[0];
String projectKey = (String)jiraProject[1];
String projectName = (String)jiraProject[2];

Liferay WOL portlets in community pages

Liferay have a set of portlets called World of Liferay (WOL) portlets. Under this category there are list of portlets such as JIRA, SVN, Summery, Friends, summery wall etc. By default these portlets are working only if they are placed on a private page. (eg:My Places -> My Community -> Private pages). If we place these portlets in a community page it will give an error messaye "This application will only function when placed on a user page"

I wanted to place the JIRA portlet in one of the community page and display the content successfully. In order to do that I updated tomcat-6.0.18\webapps\wol-portlet\init.jsp file with the following code.

WindowState windowState = renderRequest.getWindowState();

String currentURL = PortalUtil.getCurrentURL(request);

Group group = GroupLocalServiceUtil.getGroup(scopeGroupId);

Organization organization = null;
User user2 = null;

if (group.isOrganization()) {
organization = OrganizationLocalServiceUtil.getOrganization(group.getClassPK());
}

else if (group.isCommunity()) {
user2 = themeDisplay.getRealUser();
}
else if (group.isUser()) {
user2 = UserLocalServiceUtil.getUserById(group.getClassPK());

}

DateFormat dateFormatDate = DateFormat.getDateInstance(DateFormat.LONG, locale);

dateFormatDate.setTimeZone(timeZone);

DateFormat dateFormatDateTime = DateFormats.getDateTime(locale, timeZone);

NumberFormat numberFormat = NumberFormat.getNumberInstance(locale);

Configuring the JIRA Portlet in Liferay

This is how I configured the world of Liferay portlet-JIRA in Liferay. You can follow the below steps in order to configure that portlets. I'm using atlassian-jira-standard-3.7.4-standalone as my JIRA Installation and liferay-portal-tomcat-6.0-5.2.3 as my Liferay instance.

Installing JIRA:
See my post "Installing JIRA" to install the atlassian-jira-standard-3.7.4-standalone.

Installing MySQL and Connecting JIRA:

In order to configure the JIRA portlet in Liferay, you need to set the JIRA database in to a valid database. You can use any database such as MySQL, Oracle, DB2, Firebird, MaxDB,HSQL etc. Here are the steps to configure the MySQL database for the JIRA. You can find a complete instructions from http://www.atlassian.com/software/jira/docs/v3.7.4/databases/mysql.html

• I'm using MySQL server 5.0 as my MySQL installation.
• Create a database for JIRA to store issues (e.g. jiradb). I created it using MySQL Command Line Client.

create database jiradb;

• Download the MySQL Connector/J JDBC driver from http://mysql.cs.pu.edu.tw/Downloads/Connector-J/mysql-connector-java-5.1.12.zip
• Add the MySQL JDBC driver jar (mysql-connector-java-3.x.x-bin.jar) to the atlassian-jira-standard-3.7.4-standalone/common/lib/ directory.
• Edit conf/server.xml and customise the username, password, driverClassName and url parameters for the Datasource.You have to edit followings. Also delete the minEvictableIdleTimeMillis and timeBetweenEvictionRunsMillis parameters.

username="root"
password=""
driverClassName="com.mysql.jdbc.Driver"
url="jdbc:mysql://localhost/jiradb?autoReconnect=true&useUnicode=true&characterEncoding=UTF8"

• Edit atlassian-jira/WEB-INF/classes/entityengine.xml. You have to edit following parameters.

change the field-type-name attribute to mysql
delete this, if it exists: schema-name="PUBLIC"

• Then you can start the JIRA using bin/startup.bat

Configuring Liferay:

Since World of Liferay-JIRA portlet is not an out of the box portlet, you have to configure it before using it. You can find a forum on doing this at http://www.liferay.com/community/forums/-/message_boards/message/4574654
Following is the list of steps that I have followd to configure that portlet.

• liferay-portal-5.2.3\tomcat-6.0.18\webapps\wol-portlet\jira\view_jira_project.jspf uses hard coded urls to issues.liferay.com. I modified them to my JIRA installation URL. So now it looks like

String jiraURL = "http://localhost:8090/secure/Dashboard.jspa?reset=true&pid=" + projectId;

• I updated wol-portlet\WEB-INF\jdbc.properties with appropriate values to access the JIRA database. So now it looks like:
  

jira.driverClassName=com.mysql.jdbc.Driver
jira.url=jdbc:mysql://localhost/jiradb?autoReconnect=true&useUnicode=true&characterEncoding=UTF8
jira.username=root
jira.password=

• I Updated wol-portlet\WEB-INF\classes\portlet.properties to turn on jira synchronization.Now it looks like:

include-and-override=portlet-ext.properties
jira.synchronization.interval=5

• After that Strat the liferay using bin/startup.bat

Adding the JIRA portlet to Liferay and customize:

Following are the steps that I followed in order to add the JIRA portlet.

• Login to the Liferay with your user name and password. (May be default user name= test@liferay.com password=test)
• Go to My Places -> My Community -> Private Pages and click add application.
• Select and add JIRA and Summery portlets under the World of Liferay category.
• Then you should see the "Set JIRA login" link in the JIRA portlet and set the login name here.
• If you get any porblem with setting it from there, go to summery portlet "edit" link and set it.
• After return to the previous page you should displayed the JIRA portlet.

Liferay Plugins SDK configuration

Liferay's Plugins Software Development Kit is the recommended method of Liferay team to create plugins although it is not the only method. Plugins are themes and portlets. You can add functionality to Liferay by creating portlets and themes for it. In order to use it first you have to install some tools and configure SDK.

Install Ant

• Plugins SDK requires that you have Ant 1.7.0 or higher installed.
• Download the latest version of Ant from http://ant.apache.org
• Uncompress to any folder you choose.
• Next, set an environment variable called ANT_HOME which points to the folder to which you uncompress Ant.

- On Windows by going to Start -> Control Panel, and double-clicking the System icon.
- Go to Advanced, and then click the Environment Variables button. Under System Variables, select New.
- Make the Variable Name ANT_HOME and the Variable Value the path to which you installed Ant (e.g: C:\Ant\apache-ant-1.7.1), and click OK.

• To set proper memory settings for building projects.

- Select New again. Make the Variable Name ANT_OPTS and the Variable Value "-Xms256M -Xmx512M" and click OK.

• Go to PATH environment variable. Select it and select Edit. Add %ANT_HOME%\bin to the end or beginning of the PATH and click OK.
• To test whether you have properly installed Ant Go to command prompt type ant and press enter.
• If you get a build file not found error, you have correctly installed Ant.

Configure Liferay Plugins SDK

• Download the Plugins SDK archive from Liferay downloads page.

http://www.liferay.com/web/guest/downloads/additional

• Unzip the file to any place in which to you wish to carry your works.
• In that unzipped folder there is a file called build.properties and open it using text editor or IDE.
• This file contains the settings for where you have Liferay installed and where your deployment folder is going to be.
• But we can’t customize this file. Instead, create a new file in the same folder called build.${user.name}.properties, where ${user.name} is your user ID on your machine.

You can find your machine ID by right click My Computer -> properties.
Eg: build.Jane.properties where Jane is the Machine ID.

• Most probably you will need to customise following properties and save the file.

- app.server.dir=
- javac.compiler=

• app.server.dir: This is the folder into which you have installed your application server.
• java.compiler: Defaults to the standard Java compiler, modern, from your JDK.
• In my case build.${user.name}.properties looks as below.

app.server.dir=G:\liferay-portal-tomcat-6.0-5.2.3\liferay-portal-5.2.3\tomcat-6.0.18
javac.compiler=modern

• Now you are ready to use Liferay Plugins SDK.

SSO in Liferay

Single Sign On(SSO) is the feature which allows the user to log in to the portal once and access all the portlets according to his permissions, with out sign in again for different portlets. In order to set up SSO between Liferay portal and the existing portlets, I decided to integrate Liferay web portal with the JA-SIG CAS (Central Authentication Service) Server. First I read articles and research papers about the SSO and got an understanding about what is actually meant by SSO and how it works with Web Portals. Then I clearly identified the procedure of SSO and the following diagram illustrates it.



After that I read about how to install CAS server. In order to do that I downloaded CAS Server and I installed Tomcat Server. After setting up CAS server in the Tomcat installed CAS client in Liferay. After that I generate an SSL cert for the CAS server. Finally I did all the configurations on Liferay portal in order to work with Liferay.

LDAP authentication in Liferay

User management is one of the most critical part of my Workflow Management System(WMS), since it is necessary to manage the users properly and efficiently. Although Liferay has its own method to manage users it is not suitable for the WMS because of several reasons. I start to do research and implement user management system for the WMS. First I decided to integrate Liferay with LDAP (Lightweight Directory Access Protocol) directories to store the authentication and authorization policies. I decided to do that because The LDAP directories are made for high performance lookups thus addressing the high traffic load and the LDAP directories are often the source for the single sign on system to authenticate against.

In order to do that I used Apache Directory Server, which is an embeddable directory server which is written in Java. I also used JXplorer LDAP browser for the directory browsing purposes. First I input users to the system using LDAP browser. Then I connected the Server with relevant ports and finally I changed the settings of Liferay portal in order to integrate it with LDAP Directory. After doing these things I was able to authenticate users to the system via LDAP directory.

You can find the full description of integrating LDAP with Liferay from here.

Integrate Alfresco with Liferay

Following are the steps to integrate Liferay portal 5.2.3 and the Alfresco 4.2.1

• Download the Alfresco .war file

http://downloads.sourceforge.net/lportal/liferay-portal-alfresco-4.2.1.war?download

• Rename the file to “alfresco.war”.
• Login to the Liferay as administrator.
• Go Dock -> Add Application -> Install more Applications -> Upload File.
• Browse and select the path of “alfresco.war” and click install.
• Then go back and go to Dock -> Add Application.
• Now you can see the Alfresco portlet under content management category.
• If it is not displayed their refresh the page or restart the portal server.
• You can log in to the alfresco using username : admin and password: admin.

Liferay and SOA

One of the main characteristic of a portal is that the origin of the data that it holds can be initialized at any place and integration of this information is handled by the Web portal. Another important characteristic of a portal is different users who have different roles within the organisation must be able to see different views of the same web portal depending on permissions they have. The main component of the portal is the portlets which are self contained interactive elements written according to a particular standards like JSR-168, JSR-286 etc. Portlets are the components that render the markup fragment that represents the applications. Because of these characteristics of the web portal and the portlets it is possible to extend the Liferay using the Service Oriented Architecture (SOA).

All the applications that we integrate with the Liferay are portlets and since portlets are developed independent from the portal itself and loosely coupled with the portal, it is possible to use SOA. Since Liferay portal uses and open SOA framework and provides tools and framework to extend SOA to other enterprise applications, SOA can be easily implemented. The Liferay provides mechanism to the developers to quickly implement the SOA concept. The Liferay portal comes packaged with a powerful tool known as ServiceBuilder which helps to develop the SOA. There are lot of technologies needed for SOA such as Web Services, Spring and Hibernate and it is necessary to write and configure lot of files when implementing SOA. But the ServiceBuilder of Liferay automates most of these things and the only thing the developer has to do is implement the business logic which is the key aspect of the portal. So it is possible to extend the Liferay using these things to implement powerful SOA.

When implementing SOA with the Liferay the first thing we have to do is define the data model. In order to do that it is necessary to write an XML file called service.xml with all the necessary fields, keys and finder methods. After that we need to run the ServiceBuilder using Ant and number of files are generated. Among these files, Spring configuration files, SOAP and Tunnel classes, WSDL files Javascript web services methods, Data model classes, Hibernate classes, SQL create and index scripts are included.

After Defining the data model it is necessary to declare the business methods. We can declare any business methods in Remote and Local service classes. After run the ServiceBuilder task in Ant again, those methods will be propagated into the SOAP and Tunnel classes and WSDL files and Javascript Web Services methods.

The final step in implementing SOA is implementing the business logic. The remote implementation class do security and permission checks like any other J2EE application. The local implementation class contains the business logic that we allow the trusted sources to invoke. After doing all these three steps we have to compile the code and SOA is implemented.

Web Services for Remote Portlets (WSRP) is another way of implementing SOA with SDWMS. WSRP is a specification which defines the methods on how to combine SOAP based Web Services that generate mark-up fragments within a portal. The main goal of the WSRP is to bring the Web Services and the benefits of SOA to the end users. WSRP is built on top of the existing Web Services Standards such as SOAP, WSDL and UDDI.

Web Services allows to re-use the back end services and WSRP allows to reuse the user interface. As an example we can use this with Liferay as follows. If we decide to provide the users of the SDWMS to retrieve news alerts or price of stocks, we can first look whether there is already Web services which provide these functionalities. We can search in UDDI registries for web services portlets to find a web service which provides this functionality. After finding such a portlet, the process of adding it to the portal is simple. Since the portlet is being consumed through WSRP we don’t need to do any custom coding or deployment activity.

WSRP architecture defines three types of actors. They are,

• WSRP producer – In the above example it is the web service that which offers portlets which implement the WSRP interfaces and the news alerts or stock quotes functionality.
• WSRP portlet – This is the pluggable user interface component that runs inside the WSRP producer and it can be accessed remotely through the interface define by the producer.
• WSRP consumer – This is the client that invokes the WSRP web services offered by the producer. In above scenario it is the SDWMS portal.

The process of Discover, publish and run the web services using WSRP is shown by the following figure.

Working With Liferay Portal.

As the world's leading open source portal platform, Liferay portal provides a unified web interface to the data and tools scattered across many sources. Few months ago I started to work with Liferay in order to develop an Workflow Management System. I guess I'm in the correct track by selecting the Liferay as my portal platform. :)

Personalization, Content Aggregation, Authentication are major key words associated with a portal. Let's see how to work around with them soon !!!!!