This topic applies only to the IBM Business Automation Workflow Advanced
configuration.

Accessing the local interface of the session bean

Draft comment:
This topic only applies to BAW, and is located in the BAW repository. Last updated on 2025-03-13 12:15

Draft comment:
This topic was viewed 11 times since its publication

An EJB client application for BPEL processes or human tasks accesses the local interface of the session bean through the local home interface of the bean.

About this task

The session bean can be either the BusinessFlowManager session bean for process applications or the HumanTaskManager session bean for human task applications.

Procedure

Add a reference to the local interface of the session bean to the application deployment descriptor.
Add the reference to one of the following files:
- The application-client.xml file, for a Java™ Platform, Enterprise Edition (Java EE) client application
- The web.xml file, for a web application
- The ejb-jar.xml file, for an Enterprise JavaBeans (EJB) application
The reference to the local home interface for process applications is shown in the following example:
```
<ejb-local-ref>
	<ejb-ref-name>ejb/LocalBusinessFlowManagerHome</ejb-ref-name>
	<ejb-ref-type>Session</ejb-ref-type>
	<local-home>com.ibm.bpe.api.LocalBusinessFlowManagerHome</local-home>
	<local>com.ibm.bpe.api.LocalBusinessFlowManager</local>
</ejb-local-ref>
```
The reference to the local home interface for task applications is shown in the following example:
```
<ejb-local-ref>
	<ejb-ref-name>ejb/LocalHumanTaskManagerHome</ejb-ref-name>
	<ejb-ref-type>Session</ejb-ref-type>
	<local-home>com.ibm.task.api.LocalHumanTaskManagerHome</local-home>
	<local>com.ibm.task.api.LocalHumanTaskManager</local>
</ejb-local-ref>
```
If you use IBM® Integration Designer to add the EJB reference to the deployment descriptor, the binding for the EJB reference is automatically created when the application is deployed. For more information on adding EJB references, refer to the Integration Designer documentation.

Locate the local home interface of the session bean through the Java Naming and Directory Interface (JNDI).

The following example shows this step for a process application:

// Obtain the default initial JNDI context
InitialContext initialContext = new InitialContext();

// Lookup the local home interface of the BusinessFlowManager bean
 
 LocalBusinessFlowManagerHome processHome = 
      (LocalBusinessFlowManagerHome)initialContext.lookup
      ("java:comp/env/ejb/LocalBusinessFlowManagerHome");

The local home interface of the session bean contains a create method for EJB objects. The method returns the local interface of the session bean.

Access the local interface of the session bean.
The following example shows this step for a process application:
```
LocalBusinessFlowManager process = processHome.create();
```
Access to the session bean does not guarantee that the caller can perform all of the actions provided by the bean; the caller must also be authorized for these actions. When an instance of the session bean is created, a context is associated with the instance of the session bean. The context contains the caller's principal ID, group membership list, and indicates whether the caller has one of the Business Process Choreographer Java EE roles. The context is used to check the caller's authorization for each call, even when administrative security is not set. If administrative security is not set, the caller's principal ID has the value UNAUTHENTICATED.
Call the business functions exposed by the service interface.
The following example shows this step for a process application:
```
process.initiate("MyProcessModel",input);
```
Calls from applications are run as transactions. A transaction is established and ended in one of the following ways:
- Automatically by WebSphere® Application Server (the deployment descriptor specifies TX_REQUIRED).
- Explicitly by the application. You can bundle application calls into one transaction:
```
// Obtain user transaction interface
UserTransaction transaction= 
       (UserTransaction)initialContext.lookup("java:comp/UserTransaction");

// Begin a transaction
transaction.begin();

// Applications calls ...

// On successful return, commit the transaction
transaction.commit();
```
Tip: To prevent database deadlocks, avoid running statements similar to the following in parallel:
```
// Obtain user transaction interface
UserTransaction transaction= 
       (UserTransaction)initialContext.lookup("java:comp/UserTransaction");

transaction.begin();

//read the activity instance 
process.getActivityInstance(aiid);     
//claim the activity instance
process.claim(aiid);               
     
transaction.commit();
```
The getActivityInstance method and other read operations set a read lock. In this example, a read lock on the activity instance is upgraded to an update lock on the activity instance. This can result in a database deadlock when these transactions are run in parallel

Example

Here is an example of how steps 2 through 4 might look for a task application.

//Obtain the default initial JNDI context
InitialContext initialContext = new InitialContext();

//Lookup the local home interface of the HumanTaskManager bean
LocalHumanTaskManagerHome taskHome = 
        (LocalHumanTaskManagerHome)initialContext.lookup
        ("java:comp/env/ejb/LocalHumanTaskManagerHome");

...
//Access the local interface of the session bean
LocalHumanTaskManager task = taskHome.create();

...
//Call the business functions exposed by the service interface
task.callTask(tkiid,input);