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By Satya Ranja, January 2009
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This article describes portlet development using NetBeans
Portal Pack 3.0.2 and Java Application Platform SDK Update 7.
Note: See NetBeans Portal Pack 3.0.2 Release
Notes and Installation
Instructions.
Contents
Introducing
NetBeans Portal Pack 3.0.2
Downloads
Prerequisites
Configuration
Steps
Scope
Example:
HelloWorld Portlet
Appendix
References
Introducing NetBeans Portal Pack 3.0.2
NetBeans Portal Pack 3.0.2 makes portlet development as
easy as writing a normal Java applications; with all the features of
portlets made available to you at the click of a mouse. NetBeans
Portal Pack 3.0.2 is a plugin that extends the functionality of
NetBeans IDE 6.7.1 to enable creation of portlets.
This article describes the new features in NetBeans
Portal Pack 3.0.2. The new features supported in this version of
Portal Pack are:
- Support for Java
Portlet Specification
2.0 (JSR 286)
- Wizard-based portlet filter support
- Drag-and-drop support for public render parameters
- Deployment support on OpenPortal Portlet Container 2.1
- Eventing Storyboard for JSR 286 eventing
- Visual Portlet Builder plugin to build JSF portlet
Downloads
The distribution of the software required to create portlet
applications can be found at:
Prerequisites
You can install the above mentioned software in any of the
following ways:
- Download the Java EE 5 Tools Bundle Update 7 to get
all the required components for portlet development.
The Java EE 5 Tools Bundle Update 7 contains the following
software for portlet development:
- NetBeans IDE 6.7.1
- NetBeans Portal Pack 3.0.2
- Sun GlassFish Enterprise Server v2.1 (formerly Sun Java
System Application Server)
- Portlet Container 2.1
- Download and install all required software separately to
set up portlet development environment.
The following individual components are required to set up the portlet
development environment in NetBeans IDE 6.7.1:
- NetBeans Portal Pack 3.0.2 on NetBeans IDE 6.7.1
- Java Application Platform SDK Update 7 with OpenPortal
Portlet Container
2.1
NetBeans Portal Pack 3.0.2 can be used to deploy and
undeploy
portlets on an already installed portlet container in any of the
following
scenarios:
- A Portlet Container downloaded and installed on a
GlassFish application server (see Downloads).
- A Portlet Container bundled with the Java Application
Platform
SDK Update 7 release.
For installation instructions, visit:
Configuration Steps
You will need to configure a portlet container instance inside
your NetBeans IDE. Please see the Appendix
for further details.
Scope
In this article, we will provide a step-by-step walkthrough
on:
- How to write your first "Hello World" portlet.
- How to write a simple filter that tracks and logs the
number of users who have accessed the
portlet. This sample demonstrates the Portlet Filter feature introduced
in
the JSR 286 Public Review Draft.
Example: HelloWorld Portlet
The following section discusses how to create a Hello World
portlet.
Create a New
NetBeans Project
- Select File > New Project > Web > Web Application.
- Select an instance of "OpenPortal Portlet Container 2.1"
as
the server. If you have not already configured your portlets
to run on a portlet container, click the Add
button and select the portlet container of your choice. A drop-down
list provides the various instances that you can configure your portlet
application to run on.
- Enter the project name as "HelloWorld" and click Next.
- Select "Portlet Support" in Framework selection panel.
Here, you also need to select the Portlet Version as 2.1 and set the
Create
Portlet and Create Jsps options.
Figure
1: New Portlet Wizard
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- Click on Finish.
The Hello World portlet application is now created with a
default HelloWorld portlet class file and the relevant JSP files. The portlet.xml
file is updated with the portlet created in the above step. The
HelloWorld portlet will display the string “HelloWorld - VIEW MODE”
when it is executed and viewed on a browser.
The following section describes how to run portlets in
NetBeans IDE 6.7.1.
Execution
To run the portlet, right-click on the project and click
"Run." The IDE
will first deploy the portlet on the portlet container configured at
the time of the project creation.
When the deployment succeeds, the IDE will open the NetBeans configured
browser and display the
portlet "Hello World" within the portlet container driver.
Deployment and
Undeployment
The following section provides an approach to deploy the
portlet application that one just created.
- Right-click on the project and select "Clean and Build."
The IDE will
delete all
the class files and any WAR (web archive) files created earlier. The
IDE will recompile and create the WAR files afresh.
- Right-click on the project and select "Deploy." The IDE
will undeploy the portlet if it is already deployed
and re-deploy.
This way, the portlet will reflect any new changes that were made to
the same portlet deployed earlier.
- In the Run Time tab, click
Services->Servers->OpenPortal Portlet
Container 2.1 global->portlets to view the list of
deployed portlets.
You can either undeploy the portlets or view the portlets at
this point by right-clicking on the portlet node.
Skeleton Walkthrough
This section provides an overview of the basic template of a
portlet application created by NetBeans Portal Pack 3.0.2.
- Note that the portlet plugin creates all the files
required for the creation of the portlet.
- Observe that there are three files created in the Web
Pages folder. The JSP files are created
under the WEB-INF/jsp folder. They are: HelloWorld_view.jsp,
HelloWorld_edit.jsp, and HelloWorld_view.jsp. These JSP files
help in defining the various modes in which a portlet can execute. The
JSP files need to be updated to include any presentation logic.
- Note that there is a Java file created in the source
folder with the package name specified at the time of creating the
project. All the
necessary portlet packages that are needed
to start developing a portlet application are imported upfront. This
Java file handles the portlet request to process the presentation logic
of the application.
public void doView(RenderRequest request,RenderResponse response)
throws PortletException,IOException {
response.setContentType("text/html");
PortletRequestDispatcher dispatcher =
getPortletContext().getRequestDispatcher("/WEB-
INF/jsp/HelloWorld_view.jsp");
dispatcher.include(request, response);
}
public void doEdit(RenderRequest request,RenderResponse response)
throws PortletException,IOException {
response.setContentType("text/html");
PortletRequestDispatcher dispatcher =
getPortletContext().getRequestDispatcher("/WEB-
INF/jsp/HelloWorld_edit.jsp");
dispatcher.include(request, response);
}
public void doHelp(RenderRequest request, RenderResponse response)
throws PortletException,IOException {
response.setContentType("text/html");
PortletRequestDispatcher dispatcher =
getPortletContext().getRequestDispatcher("/WEB-
INF/jsp/HelloWorld_help.jsp");
dispatcher.include(request, response);
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- Traverse to the web->WEB-INF directory to view the
portlet.xml configuration file. This configuration file is created at
the time of creating the project.
Creating a Portlet Filter Class and Filter Mapping
Let us now write a simple filter that tracks the number of
times a
portlet has been accessed. To
know more about Portlet Filters and Filter Mapping, see the JSR 286
Portlet
Specification and Understanding
Portlet Container 2.1 Software.
To do this, create a Portlet Filter class:
- Select the HelloWorld application, right-click and choose
New
> Other > Portlets > Portlet
Filter. If you have previously created a portlet filter, this
option is readily available when you click New. The
IDE caches the requests by
the user and presents them when you use the next time.
- Enter the following details and click Next:
- The Filter Class name as HitCounterFilter.
- Package structure with which you want to create the
portlet.
- The location where you want the sources to be available
(the default is Source Packages).
- Select "Render" as the Filter Type for this portlet.
Figure
2: Portlet Filter Wizard
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- To map the filter to the portlet, click New and choose
HelloWorld
portlet and click Finish.
You would find that the a filter class (HitCounterFilter.java)
has been
created and is mapped to the portlet. The following snippet shows the
mapping in the portlet.xml file:
<filter>
<filter-name>HitCounterFilter</filter-name>
<filter-class>com.test.HitCounterFilter</filter-class>
<lifecycle>RENDER_PHASE</lifecycle>
</filter>
<filter-mapping>
<filter-name>HitCounterFilter</filter-name>
<portlet-name>HelloWorld</portlet-name>
</filter-mapping>
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Update the doFilter()
method of the filter class (HitCounterFilter.java)
to get the value of the attribute "hitCounter." This
instruction will log the
number of times the user has accessed the portlet:
public void doFilter(RenderRequest renderRequest, RenderResponse renderResponse,
FilterChain filterChain) throws IOException, PortletException {
if (filterConfig == null) {
return;
}
//add pre processing code here
filterChain.doFilter(renderRequest, renderResponse);
PrintWriter writer = renderResponse.getWriter();
int counter = getCounter();
writer.print("<br>===============");
writer.println("<br>The number of times this portlet is accessed: " + counter);
writer.println("<br>===============");
}
private int getCounter() {
Integer counter = (Integer) filterConfig.getPortletContext()
.getAttribute("hitCounter");
int count = 1;
if (counter == null) {
counter = new Integer(count);
} else {
count = counter.intValue();
counter = new Integer(++count);
}
filterConfig.getPortletContext().setAttribute("hitCounter", counter);
return count;
}
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Build and deploy the portlet.
When the portlet is executed, it will display the number
of times this portlet has been accessed.
Figure 3:
Output of the HitCounter Portlet Filter
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The same filter can also be applied to different portlets by
mapping the filter to the portlet in the portlet.xml
file. Similarly multiple filters can be mapped to a
single portlet. The order of execution of the filter will follow the
order in which the mapping is defined in the portlet.xml
file. To map a filter
to other portlets please check Appendix.
Please send feedback to users@portalpack.netbeans.org.
Appendix
Configure
Portlet Container in NetBeans
- Select Tools > Servers.
- Click Add Server.
- Select "OpenPortal Portlet Container 2.1" from list of
servers.
- Enter GlassFish Installation Home, for example,
"/software/glassfish." or SDK Home.
- Enter GlassFish administrator password. The default
password is 'adminadmin'.
Click Next.
- Provide the installed Portlet Container Home. For
example,
"$GLASSFISH_HOME/domains/YOUR_DOMAIN/portlet-container." Click Finish.
Portlet Filter
Mapping
You can map a Portlet Filter to other Portlets. To
do this:
- Expand portlet.xml node in the Project explorer window.
- Expand "Filters" node:
Figure
4: Expand dtls
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- Select a filter and drag it to a portlet to which you want
to map to. A mapping is created in the portlet.xml file between the
selected filter and the portlet.
Public Render Parameters
To add a public render parameter:
- Expand portlet.xml node in the Project explorer window.
- Right click "Public Render Parameters" node.
- Select "Add Public Render Parameter."
- Enter the required details for the render parameters. The
fields Identifier and Local Part are mandatory. Click OK.
- This will add a public render parameter entry in the
portlet.xml file.
- To associate this newly created public render parameter to
a
portlet, just drag that public render parameter node to appropriate
portlet node.
References
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