Aspectj Cookbook

2017-07-07 02:10:07

Recipe 5.3. Capturing the Object Handling the Exception

Problem

Within the advice triggered by a join point captured using the handler(TypePattern) pointcut, you want to access the object that caught the exception and use it within the corresponding advice.

Solution

Combine the this([Type | Identifier]) pointcut with the handler(TypePattern) pointcut to expose the exception handling object as an identifier on your pointcut that can then be passed to the corresponding advice.

Discussion

Example 5-3 shows how the exception handling MyClass object is passed to the before( ) advice as the myObject identifier on the myExceptionHandlerPointcut pointcut.

Example 5-3. Accessing the object that contained the catch block that handled the MyException exception

public aspect AccessHandlingObject { pointcut myExceptionHandlerPointcut(MyClass myObject) : handler(MyException) && this(myObject); // Advice declaration before(MyClass myObject) : myExceptionHandlerPointcut(myObject) { System.out.println( "-------------- Aspect Advice Logic ---------------"); System.out.println( "In the advice picked by " + "myExceptionHandlerPointcut( )"); System.out.println( "Signature: " + thisJoinPoint.getStaticPart( ).getSignature( )); System.out.println( "Source Line: " + thisJoinPoint.getStaticPart( ).getSourceLocation( )); System.out.println("Exception caught by:" + myObject); System.out.println( "--------------------------------------------------"); } }