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| e-docs > WebLogic Platform > WebLogic Integration > BPM Topics > Programming BPM Client Apps > Connecting to the Process Engine |
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Programming BPM Client Apps
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Connecting to the Process Engine
This section explains how a to connect to the WebLogic Integration process engine and access the features of the business process management (BPM) framework. It includes the following topics:
Accessing the API Session EJBs
As with any EJB, you must access the BPM API session EJBs using the home and remote interfaces. The following table lists the home and remote interfaces available for this purpose.
To access BPM API session EJBs and their methods, you must perform the following steps:
The following sections describe these steps in detail.
Step 1: Look Up a Session EJB Home Interface in JNDI
The BPM session EJBs are exposed to client applications as part of the WebLogic Server JNDI namespace.
You can look up a session EJB home interface by first establishing a JNDI context (java.naming.Context). The most common way of doing this is by instantiating a javax.naming.InitialContext object. For client applications that require a specific security context for authorization to access EJBs and their methods, you must also pass security credentials (user name and password, for example) to the InitialContext() constructor.
For example, the following method, excerpted from the JSP worklist example, creates an initial context, passing the specified URL, user ID, and password as the context environment.
public Context getInitialContext(
String user,
String password,
String url
) throws NamingException
{
// Get an InitialContext
Properties h = new Properties();
h.put(Context.INITIAL_CONTEXT_FACTORY,"weblogic.jndi.WLInitialContextFactory");
h.put(Context.PROVIDER_URL, url);
if (user != null) {
h.put(Context.SECURITY_PRINCIPAL, user);
if (password == null)
password = "";
}
h.put(Context.SECURITY_CREDENTIALS, password);
return new InitialContext(h);
}
For more information, see the javax.naming.InitialContext() Javadoc. For more information about the JSP worklist, see JSP Worklist Example.
Once the JNDI context is defined, you can use the JNDI context lookup() method to access the session EJB home interface.
For example, to look up the Worklist session EJB home interface, and store the object reference to the worklistHome variable, execute the following statements:
Context context = getInitialContext(url, userId, password);
Object result = context.lookup("com.bea.wlpi.Worklist");
WorklistHome worklistHome =(WorklistHome)
PortableRemoteObject.narrow(result, WorklistHome.class);
Similarly, to look up the WLPIPrincipal session EJB home interface and store the object reference to the principalHome variable, execute the following statements:
Context context = getInitialContext(url, userId, password);
object result = context.lookup("com.bea.wlpi.WLPIPrincipal");
PrincipalHome prinicipalHome=(PrincipalHome)
PortableRemoteObject.narrow(result,
WLPIPrinicipalHome.class);
Note: The PortableRemoteObject.narrow() method used in the previous examples ensures that the remote object is cast to the desired type. Use of this method is required if the system is configured to use RMI-IIOP; otherwise, its usage is optional (but recommended). For more information, see the javax.rmi.PortableRemoteObject class Javadoc.
Step 2: Create a Remote Session Object Using the Home Interface
Once you have a reference to a home interface, you can use the home interface object create() method to access a remote session object (EJBObject).
For example, to create an EJBObject for the Worklist session EJB and store the object reference to the worklist variable, execute the following statement:
Worklist worklist = worklistHome.create();
Similarly, to create an EJBObject for the WLPIPrincipal session EJB and store the object reference to the principal variable, execute the following statement:
WLPIPrincipal wlpiprincipal = principalHome.create();
Using the Convenience Methods to Access EJBs
The com.bea.wlpi.client.common.WLPI class provides a set of convenience methods for accessing session EJBs. The following table summarizes these methods.
For more information, see the com.bea.wlpi.client.common.WLPI Javadoc.
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