Aspectj Cookbook

2017-07-07 02:10:07

Recipe 5.2. Capturing the Thrown Exception

Problem

Within the advice triggered by a join point captured using the handler(TypePattern) pointcut, you want to access the exception that was being caught by the catch block within the corresponding advice.

Solution

Combine the args([Types | Identifiers]) pointcut with the handler(TypePattern) pointcut to expose the caught exception as an identifier on your pointcut that can be passed to the corresponding advice.

Discussion

Example 5-2 shows how the MyException exception is passed to the before( ) advice as the exception identifier on the myExceptionHandlerPointcut pointcut.

Example 5-2. Accessing the caught MyException exception

public aspect AccessThrownException { pointcut myExceptionHandlerPointcut(MyException exception) : handler(MyException) && args(exception); // Advice declaration before(MyException exception) : myExceptionHandlerPointcut(exception) { 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:"); exception.printStackTrace( ); System.out.println( "--------------------------------------------------"); } }