Recipe10.2.Capturing All Join Points Within a Program s Control Flow, Excluding the Initial Join Point

Recipe 10.2. Capturing All Join Points Within a Program's Control Flow, Excluding the Initial Join Point

Problem

You want to capture all join points encountered within the program control flow after the initiating join point selected by a separate pointcut.

Solution

Use the cflowbelow(Pointcut) pointcut. The syntax of the cflowbelow(Pointcut) pointcut is:

pointcut <pointcut name>(<any values to be picked up>) : cflowbelow(<pointcut>);

Discussion

Example 10-2 shows the cflowbelow(Pointcut) pointcut being used to capture all of the join points that occur after an initial join point captured by the callInitialPointcut( ) pointcut.

Example 10-2. Using the cflowbelow(Pointcut) pointcut to capture join points after an initially captured join point

public aspect CFlowBelowRecipe  {    /*    Specifies calling advice whenever a method    matching the following rules gets called:        Class Name: MyClass    Method Name: foo    Method Return Type: void    Method Parameters: an int followed by a String    */    pointcut callInitialPointcut( ) : call(       void MyClass.foo(int, String));    /*            Specifies calling advice whenever a join point is encountered            after but excluding the initial join point that triggers the pointcut            that is specified in the parameter:                Pointcut Name: callInitialPointcut    */    pointcut cflowPointcut( ) : cflowbelow(callInitialPointcut( ));    // Advice declaration    before( ) : cflowPointcut( ) && !within(CFlowBelowRecipe +)    {       System.out.println(          "------------------- Aspect Advice Logic --------------------");       System.out.println(          "In the advice attached to the cflowbelowPointcut point cut");       System.out.println(          "Join Point Kind: " + thisJoinPoint.getKind( ));       System.out.println(          "Signature: "             + thisJoinPoint.getStaticPart( ).getSignature( ));       System.out.println(          "Source Line: "             + thisJoinPoint.getStaticPart( ).getSourceLocation( ));       System.out.println(          "------------------------------------------------------------");    } }

Figure 10-2 shows how the cflowbelow(Pointcut) pointcut can be applied.

Figure 10-2. How the cflowbelow(Pointcut) pointcut can be applied

This recipe differs only slightly from Recipe 10.1; the difference is in the number of join points that are actually captured. Whereas the cflow(Pointcut) pointcut triggers advice on all join points encountered within an initial join point's context including the initial join point, the cflowbelow(Pointcut) pointcut excludes that initial join point.

See Also

Recipe 10.1 describes the cflow(Pointcut) pointcut; Chapter 12 describes techniques for combining pointcut definitions; more information on a join point's context and environment is available in Chapter 13.