Exceptions in lifecycle callback methods (I)

[Ralph Jaus]

Dear all,

the ejb core spec says (12.4.2, page 307):

A lifecycle callback interceptor method may catch an exception thrown by another lifecycle callback interceptor method in the invocation chain

Has anybody an example on how this works ?

For example, given the following interceptor class

public class InterceptorA{
 
  @PostConstruct
  public void method(InvocationContext invocationContext) throws Exception{
 
    System.out.println("IA"); 
    throw new RuntimeException("myException"); 
 
  }
} 

How would a lifecycle callback method in a following interceptor class catch myException ?
[ October 21, 2008: Message edited by: Ralph Jaus ]

[Christophe Verré]

In an interceptor callback, you usually call proceed() to propagate the call down the chain. This is where you can catch an exception.

try {
invocationContext.proceed();
} catch( Exception e ) {
}

[Ralph Jaus]

Thank you Christophe, now it's clear.

So if there are lifecycle callback interceptors

public class InterceptorA{ 
 
  @PostConstruct
  public void methodA(InvocationContext ic) throws Exception{ 
 
     ic.proceed();  
  }
} 
 
public class InterceptorB{ 
 
  @PostConstruct
  public void methodB(InvocationContext ic) throws Exception{ 
 
     ic.proceed(); 
  }
} 
 
 
@Stateless
@Interceptors({InterceptorA.class, InterceptorB.class}) 
public class TestBean implements TestInterface{
 
  @PostConstruct
  public void method(){}
 
  ...
}

then the interceptor chain works (in principal) like

public class InterceptorA{ 
 
  @PostConstruct
  public void methodA(InvocationContext ic) thows Exception{ 
 
     //ic.proceed(); 
     [B]interceptorB.methodB(ic);[/B] 
  }
} 
 
public class InterceptorB{ 
 
  @PostConstruct
  public void methodB(InvocationContext ic) thows Exception{ 
 
     //ic.proceed(); 
     [B]testBean.method();[/B]  
  }
} 

Now the usual java exception handling can be applied.
[ October 22, 2008: Message edited by: Ralph Jaus ]