 | Level: Intermediate Peter Xu (peteryxu@us.ibm.com), Senior Consulting I/T Specialist, IBM Software Service for WebSphere, IBM
02 Feb 2006 This article shows you how to use IBM WebSphere Process Server Version 6 and IBM WebSphere Integration Developer Version 6 to integrate existing J2EE applications without making changes to them.
Introduction
IBM® WebSphere® Process Server is a runtime platform for business integration solutions developed using IBM WebSphere Integration Developer. Many existing business functions for a company's IT infrastructure are written based on Java™ 2 Enterprise Edition (J2EE) stateless Enterprise Java Beans (EJB). When you design and implement new business process integration applications, it is important that you have the ability to leverage and integrate these functions easily.
Overview diagram
The scenario we use in this article is pretty straightforward. It consists of one Service Component Architecture (SCA) module that has a Java component, which uses the imported EJB service.
Figure 1. Module overview
Software prerequisites
You need to install:
- WebSphere Integration Developer V6
- WebSphere Process Server V6 test environment
This article assumes that you have some knowledge of J2EE and have used WebSphere Studio Application Developer or Rational Application Developer before. To learn more about these products, visit developerWorks.
Configuration
In this section, we develop a sample EJB application and an SCA module that utilizes the EJB service.
You can begin by creating the enterprise application, package, and EJB session.
Create an enterprise application called Echo with one EJB module, EchoEJB Create a package called com.ibm.issw.poc.invokeejb. Create a stateless EJB session called Bean Echo
Figure 2. Create an EJB
Create a simple method called echoSimple, and promote it the remote interface: public String echoSimple(String name){
System.out.println("inside echoSimple");
return "Hello, " + name;
} |
Open the ejb deployment descriptor, and notice the default JNDI name for the EJB:
ejb/com/ibm/issw/poc/invokeejb/EchoHome |
Figure 3. EJB JNDI name
Create an EJB client project and jar that will be used later in the SCA module. Right-click and select EchoEJB => EJB Client Jar => Create EJB Client Project and enter EchoEJBClient in the name field.
Figure 4. EJB Client
Run and test the EJB application (see Figure 5).
Figure 5. Testing the EJB
Now, that we've created the EJB, let's integrate it.
Create an EJB component
To integrate the EJB into the WebSphere Process Server SCA component:
Create a module called InvokeEcho. From the Dependencies editor, select EchoEJBClient as the dependent Java project and click Add to add EchoEJBCLient as the dependent Java project.
Figure 6. Add dependencies
It is important to add module dependency at this point. When we add the interface later, the wizard will be able to find the remote EJB interface. From the Assembly editor, open the module, InvokeEcho in Assembly editor, add an Import component on the canvas. Change the name to EchoEJB.
Figure 7. Add the Import
Add the interface for the import:
Click the Add Interface icon. In the resulting window, select Show Java. Enter echo in the Filter by interface field. Select Echo from Matching interfaces . This interface is from project /EchoEJBClient/ejbModule (see Figure 8).
Figure 8. Add Interface for Import
Click Ok and save the module diagram.
Figure 9. Import with the interface
Generate the Session EJB Binding.
Right-click the EchoEJB import and select Generate Binding => Stateless Session Bean Binding.
Figure 10. Add Binding
Notice how the icon changed in the import (see Figure 11).
Figure 11. Import with Interface Binding
Select the Properties view and the Binding tab. You can see that the JNDI name field is now populated (see Figure 12).
Figure 12. Specify JNDI name for Binding
Create a Java Component
To create a Java Component:
Drag and drop a Java Component onto the assembly canvas and change the name to InvokeEcho (see Figure 13).
Figure 13. Add the Java Component
Create an interface called InvokeEchoInterface with a one-way operation callEcho and one input parameter:
Figure 14. Create an Interface
Select the Java component and add an interface for it, InvokeEchoInterface. Wire the InvokeEcho and EchoEJB together (see Figure 15).
Figure 15. Wire Java and Import the Component
Notice that a reference EchoPartner has been generated. We will use it in the Java Component implementation (see Figure 16).
Figure 16. Partner reference
Select and right-click the Java Component and generate the default Java implementation. When the implementation opens, replace the callEcho method with the following code: try {
System.out.println("in callEcho");
// Create an instance of the ServiceManager
ServiceManager serviceManager = new ServiceManager();
Echo echo= (Echo)serviceManager.locateService("EchoPartner");
String result = echo.echoSimple(name);
System.out.println("called imported EJB, and response is " + result);
} catch (Exception e) {
e.printStackTrace();
} |
Running and testing the scenario
To test the scenario:
Right-click InvokeEcho and select Test Component. In the test configuration, remove the emulator for EchoEJB, since we want to invoke the real EJB implementation. Enter a value for the name field and click Continue.
Figure 17. Component Test 1
Notice the expected result.
Figure 18. Component Test 2
Notice the result from the System.out.
Figure 19. Component Test 3
Congratulations, you've successfully imported and invoked the Echo EJB from the SCA component, InvokeEcho. In this scenario, the SCA module and the EJB service are running on the same server.
Conclusion
This article helped you implement a WebSphere Process Server solution that integrates EJB services. As you can see, using EJB services from an SCA component is easy to do. Reusing EJB-based services in this way creates tremendous opportunities for integration products, such as WebSphere Process Server.
Acknowledgements
The author would like to thank Sam Kaipa for reviewing this article.
Resources
About the author | | | Peter Xu is a Senior Consultant with IBM Software Services for WebSphere group. Consultants with Software Services for WebSphere help customers deploy IBM products into their organizations. Peter provides consulting services, education, and mentoring on J2EE technologies, and specifically WebSphere and WebSphere Studio products to Fortune 500 clients. You can reach him at peteryxu@us.ibm.com. |
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