Create a simple portlet

1. Set up Rational Application Developer
2. Write the portlet code
3. Compile java source
4. Create the JAR file
5. Write the portlet descriptors
6. Set up the WAR file directory structure
7. Package and deploy portlets
   1. Package a portlet and resources into a WAR file
   2. Prepare the portlet application for installation

Write the portlet code

The Hello World portlet provides an introduction to writing first portlet. The portlet is provided along with the source in the IBM Portlet Samples package, which is available from the portlet catalog by searching for navcode 1WP10017Z. See Sample portlets for more information. Hello World provides the fewest methods required for a portlet. It uses the portlet response object to write simple output directly to the portal page.

package com.ibm.wps.samples.jsr;
 
import javax.portlet.*;
import java.io.*;
 
public class HelloWorld extends GenericPortlet {
    
   public void init (PortletConfig portletConfig) throws UnavailableException, PortletException
   {
      super.init(portletConfig);
   }
 
   public void doView(RenderRequest request, RenderResponse response)
                      throws PortletException, IOException
   {
 
      // set return content type 
      response.setContentType("text/html");
      PrintWriter writer = response.getWriter();
      writer.println("<p class='wpsPortletText'>Hello Portal World!</p>");
    }
 
}

API element	IBM portlet API	Java Portlet Specification
import statements	org.apache.jetspeed.portlet	javax.portlet
Portlet class	PortletAdapter	GenericPortlet which also can throw a PortletException
Request object	PortletRequest	RenderRequest
Response object	PortletResponse	RenderResponse

Also notice that the content type must be set in the response.

Compiling Java source

Compile Java source files... Before you compile Java source, set the CLASSPATH for the compiler to find the JAR files for any portlet packages that portlet uses by running the following command:

• UNIX: ./setupcmdLine.sh
• i: setupcmdLine.sh
• Windows: setupcmdLine.bat

The following JAR files should be set in the CLASSPATH to compile portlets:
Standard portlets

Jar file	Purpose
portletapi_20.jar	This file complies with the Java Portlet Specification Version 2.0.
public_api.jar	Use this file if you use services from the Public API javadoc package.
public_api.jar + public_spi.jar	Use this file if you use services from the Public SPI javadoc package.

IBM portlets

Jar file	Purpose
wp.pe.api.legacy.jar	IBM portlet API
wp.portletservices.api.legacy.jar	Portlet services
wp.pe.rt.api.jar	Portlet menus

Then, compile the portlet using the fully qualified path to the Java portlet source.

   appserver/java/bin/javac -classpath %WAS_CLASSPATH%;path_to/portletapi_20.jar 
        com.ibm.wps.samples.jsr.HelloWorld.java  

   appserver/java/bin/javac -classpath %WAS_CLASSPATH%;path_to/portletapi_20.jar 
        com.ibm.wps.samples.v4.HelloWorld.java  

Load classes for portlets

WebSphere Portal classloading follows the WAS hierarchy for classpaths and search orders. A particular classloader can reference other classes as long as the other classes can be loaded by the same classloader or any of its ancestors, but not its children. The graphic illustrates where WebSphere Portal and portlet applications fit into the classloading hierarchy.

As illustrated, WebSphere Portal is an application extension (AEX) under WAS. Consequently, the WebSphere Portal core classes are in the classpath $PORTAL_HOME/shared/app. If an installed portlet application includes a classloader, the portlet application classloader is an application classloader (ACx) under WebSphere Portal.

If you suspect a classloading problem, ensure that the required classes are in the appropriate classpath according to the classloading hierarchy.

Create the JAR file

Next, the portlet must be packaged in the JAR file format. To create a JAR file with the name HelloWorld.jar, enter the following command:

jar -cf HelloWorld.jar HelloWorld.class

Write the portlet descriptors

The following samples can be packaged with the Hello World portlet.
Web application deployment descriptor for standard portlets:

According to the Java Portlet Specification, only Web resources that are not portlets should be declared in the web.xml. However, the following properties should be set to correspond to the portlet descriptor:

• <description/>
  describes the portlet application.

• <display-name/>
  indicates the portlet application name.

• <security-role/>
  indicates the portlet application security role mapping. Omit this tag if the portlet does not use this feature.

<?xml version="1.0" encoding="UTF-8"?>

<!DOCTYPE web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN" 
          "http://java.sun.com/dtd/web-app_2_3.dtd">

<web-app id="WebApp">

    <display-name>Hello World (JSR)</display-name>
    <description>Basic JSR 168 portlet</description>

</web-app>

Standard portlet deployment descriptor:

The following shows the minimum elements required for the standard portlet deployment descriptor.

<?xml version="1.0" encoding="UTF-8"?>

<portlet-app xmlns="http://java.sun.com/xml/ns/portlet/portlet-app_2_0.xsd" 
             version="2.0" 
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
             xsi:schemaLocation="http://java.sun.com/xml/ns/portlet/portlet-app_2_0.xsd 
             http://java.sun.com/xml/ns/portlet/portlet-app_2_0.xsd">

   <portlet>

      <portlet-name>HelloWorld portlet name</portlet-name>
      <display-name>Hello World portlet (JSR)</display-name>
      <display-name xml:lang="en">Hello World portlet (JSR)</display-name>
      <portlet-class>com.ibm.wps.samples.jsr.jsrHelloWorld</portlet-class>

      <supports>
         <mime-type>text/html</mime-type>
         <portlet-mode>view</portlet-mode>
      </supports>

      <supported-locale>en</supported-locale>
      <portlet-info>
         <title>Hello World (JSR)</title>
      </portlet-info>

   </portlet>
</portlet-app>

Set up the WAR file directory structure

Before you package portlet, the class files and resources must be arranged in the WAR file directory structure described here. A portlet application exists as a structured hierarchy of directories.

Do not package .tld files for tag libraries that are provided by the portal or application server installation with the portlet application WAR file. This includes the IBM portlet API tags, JSR 168 and 286 portlet tags and the Java Standard Tag Library (JSTL).

/	The root directory of the portlet file structure.
/images	Location for any images the required by the portlet.
/WEB-INF	Location for all protected resources. The /WEB-INF directory stores the portlet descriptor document and all of the run time executable JAR files and classes that the packaged portlet requires.

The portlet information directory is not part of the public document tree of the application. Files that reside in /WEB-INF are not served directly to a client.

/WEB-INF/lib	Location for storing portlet JAR files.
/WEB-INF/jsp	Location for JSP files. This is a suggested path name. Your JSPs can be packaged in any location. JSPs that are included inside the portlet markup should be placed under the /WEB-INF directory. You should only place them outside the /WEB-INF directory if you create direct links to them.
/WEB-INF/classes	Location for portlet class files. Individual class files should be stored in a directory structure within... /WEB-INF/classes .that reflects the class package. For example, the class HelloWorld.class, in package com.ibm.wps.samples, would be stored in... /WEB-INF/classes/com/ibm/wps/samples/HelloWorld.class
/META-INF	Location for the manifest file, manifest.mf and the Java 2 security file, was.policy (if present). The manifest is in the standard JAR file format as defined by the Java 1.3 specification. The Java 2 security policy file is used to allow a portlet to perform operations that might be restricted if Java 2 security is enabled. The contents of the /META-INF directory is not served to clients.

The application server searches for security policy files in the location of the enterprise application archive rather than the Web application archive. Therefore, the portal server copies was.policy from the appname.war/META-INF directory to the generated appname.ear/META-INF directory during deployment of a portlet WAR file.

Packaging and deploying portlets

To deploy a portlet and run it on the server, it must be packaged in the form of a Web application ARchive or WAR file. The WAR file format contains the Java classes and resources that make up one or more portlets in a portlet application. The resources can be images, JSP files, Writing the portlet descriptors, and property files containing translated message text. Packaging portlet classes, resources, and descriptive information in a single file makes distribution and deployment of portlets easier.

WebSphere Portal includes an administrative portlet for installing, uninstalling, and updating portlets. Portlets contained in WAR files have the advantage of being dynamically downloaded and installed. The portal administrator can download a WAR file from the Internet and then use the portal administration interface to install the portlet to WebSphere Portal. After installation, the portlet is ready for use and does not require the server to be restarted. To package portlet in a WAR file, you can use the JAR utility to package the portlet into a WAR file .

Because Windows limits the maximum path length to 260 characters, the name of the WAR file must be less than 25 characters. On a portal server running on Windows, installing a WAR file with a name that is more than 25 characters will result in an error.

Packaging a portlet and resources into a WAR file

Any JAR utility may be used to build a WAR file. Below are examples of how to use the JAR utility provided by WAS.

• To create a WAR file with the name HelloWorld.war and include all of the files in the /WEB-INF and /images directories:
  jar -cf HelloWorld.war images WEB-INF

• To update an existing WAR file, HelloWorld.war with a revised portlet descriptor:
  jar -uf HelloWorld.war WEB-INF/portlet.xml

• To extract the portlet descriptor from the WAR file, HelloWorld.war :
  jar -xf HelloWorld.war WEB-INF/portlet.xml

• To extract all files from an existing WAR file, HelloWorld.war:
  jar -xf HelloWorld.war

After the WAR file is created, it can be installed to WebSphere Portal as described in Portal administration portlets.

Prepare the portlet application for installation

To script deploy of portlet applications, you can provide a portlet configuration to be invoked by XML Configuration Interface (xmlaccess.sh). This method allows specifying places, pages, themes, skins, supported markups and clients, and other settings for a portlet application. This method is also useful for portlets that use messaging because these portlets have to be placed on the same page. See also: IBM WebSphere Portal Zone.

When constructing XMLAccess scripts for use in installing standard portlets, use the following values:

• uid attribute for the <web-app> element:
  Use the uid attribute of the <portlet-app/> subelement with a .webmod suffix. As described subsequently in this topic, the uid attribute of the <portlet-app/> subelement is dependent on the presence of the id attribute of the <portlet-app/> element from the portlet.xml.

• uid attribute for the <portlet-app> element:
  Use the id attribute of the <portlet-app/> element from the portlet.xml. If this value has not been specified, specify the WAR file name of the portlet application in its place. For portlet updates, the WAR file name must be the original name of the WAR file used to install the portlet application. That is, the WAR file name can be changed, but the uid must indicate the original uid used during portlet installation.

• name attribute for the <portlet> element:
  Use the content of the <portlet-name/> element from the portlet.xml.

• referenceid attribute of the <servlet> element:
  Use the content of the <portlet-name/> element from the portlet.xml appended with the .servlet suffix.

For example, a portlet application might use a portlet descriptor as follows:

<portlet-app xmlns="http://java.sun.com/xml/ns/portlet/portlet-app_1_0.xsd"
                version="1.0"
                xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
                xsi:schemaLocation="http://java.sun.com/xml/ns/portlet/portlet-app_1_0.xsd 
                                    http://java.sun.com/xml/ns/portlet/portlet-app_1_0.xsd">

        <portlet>
        <portlet-name>External Bookmarks</portlet-name>
        ...

In this example, there is no id attribute provided on the <portlet-app/> element. Therefore, the <portlet-app/> element of the XMLAccess script would use the WAR file name, as follows:

 <web-app action="update" active="true" uid="bookmarks.war.webmod">
     <url>file:///$server_root$/installableApps/bookmarks.war</url>
     <servlet action="update" 
              active="true" 
              referenceid="External Bookmarks.servlet"/>
     <portlet-app action="update" active="true" uid="bookmarks.war">
         <portlet action="update" active="true" name="External Bookmarks">
     </portlet-app>
 </web-app>

IBM portlet API examples for Hello World

package com.ibm.wps.samples.v4;
 
import org.apache.jetspeed.portlet.*;
import java.io.*;
 
public class HelloWorld extends PortletAdapter {
 
   public void init (PortletConfig portletConfig) throws UnavailableException
   {
      super.init(portletConfig);
   }
 
   public void doView(PortletRequest request, PortletResponse response)
                      throws PortletException, IOException
   {
      PrintWriter writer = response.getWriter();
      writer.println("<p class='wpsPortletText'>Hello Portal World!</p>");
   }
 
}

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN" 
                         "http://java.sun.com/dtd/web-app_2_3.dtd">
<web-app id="WebApp">
        <display-name>HelloWorld</display-name>
        <servlet id="com.ibm.wps.samples.HelloWorld.a0ae41f2d3c1001710b7b313e1a97">
        <servlet-name>HelloWorld</servlet-name>
        <servlet-class>com.ibm.wps.samples.v4.HelloWorld</servlet-class>
        </servlet>
    <servlet-mapping 
       id="ServletMapping_com.ibm.wps.samples.HelloWorld.a0ae41f2d3c1001710b7b313e1a97">
        <servlet-name>HelloWorld</servlet-name>
        <url-pattern>/HelloWorld/*</url-pattern>
    </servlet-mapping>
</web-app>

As described in Deployment descriptors, the href attribute of the <portlet/> element references the servlet ID from Web deployment descriptor.

The portlet deployment descriptor references the portlet_1.1.dtd, which portal server finds in the $PORTAL_HOME/installer/wp.ear/installableApps/wps.ear/wps.war/dtd directory. Do not package the DTD with the portlet application WAR file.

<?xml version="1.0" encoding="UTF-8"?>

<!DOCTYPE portlet-app-def PUBLIC "-//IBM//DTD Portlet Application 1.1//EN" 
             "portlet_1.1.dtd">

<portlet-app-def>
  <portlet-app uid="com.ibm.wps.samples.HelloWorld.a0ae41f2d3c1001710b7b313e1a97" 
               major-version="1" minor-version="0">

    <portlet-app-name>HelloWorld application</portlet-app-name>

    <portlet id="com.ibm.wps.samples.HelloWorld" 
             href="WEB-INF/web.xml#com.ibm.wps.samples.HelloWorld.a0ae41f2d3c1001710b7b313e1a97"
             major-version="1" minor-version="0">

      <portlet-name>HelloWorld portlet</portlet-name>

      <cache>
        <expires>0</expires>
        <shared>NO</shared>
      </cache>

      <allows>
        <maximized/>
        <minimized/>
      </allows>

      <supports>
        <markup name="html">
          <view/>
        </markup>

      </supports>
    </portlet>
  </portlet-app>

  <concrete-portlet-app uid="com.ibm.wps.samples.HelloWorld.313e1a97f47.2">

    <portlet-app-name>HelloWorld application</portlet-app-name>

    <concrete-portlet href="#com.ibm.wps.samples.HelloWorld">

      <portlet-name>HelloWorld portlet</portlet-name>
      <default-locale>en</default-locale>

      <language locale="en">
        <title>HelloWorld portlet</title>
        <title-short></title-short>
        <description></description>
        <keywords></keywords>
      </language>

    </concrete-portlet>
  </concrete-portlet-app>
</portlet-app-def>

Parent

Understand the basics

+

Search Tips   |   Advanced Search