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research:mao:iiia-examples-fixed [2010/11/24 19:25] – created etanterresearch:mao:iiia-examples-fixed [2010/11/24 19:59] (current) – etanter
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 +====== Fixed versions ======
  
 +The following example shows the "double-match problem". Here, we only see syntactic changes. The semantic change is hidden: the advice should only execute once, not twice. When changing the pointcut for JPB to ...<code>call(* foo(..)) && args(*,i)</code>... then the program should throw an exception, stating that there are different value bindings for the same joinpoint.
 +
 +<code>
 +xpi Jps{
 +    joinpointtype void JP(int i);
 +    joinpointtype void JPA(int i) extends JP;
 +    joinpointtype void JPB(int i) extends JP;
 +}
 +
 +module Base{
 +  contains C;
 +  from Jps exhibits {
 +    void JPA(int i): call(* foo(..)) && args(i,*);
 +    void JPB(int i): call(* foo(..)) && args(i,*);
 +  }
 +}
 +
 +class C {
 + static void foo(int a, int b) {
 + System.out.println("foo: "+a+","+b);
 + }
 + public static void main(String args[]) {
 + foo(1,2);
 + }
 +}
 +
 +
 +module Aspects {
 +  contains DoubleAspect;
 +}
 +
 +aspect DoubleAspect{
 + void around Jps.JP(int i) {
 + System.out.println(System.identityHashCode(thisJoinPoint));
 + System.out.println(i);
 + proceed(i * -1);
 + }
 +}
 +</code>
 +
 +This is the example of looping in the case of "extends". In our approach, there will be no looping because the aspect Asp is automatically deployed on level 1.
 +
 +<code>
 +xpi Jps {
 +    joinpointtype void JP();
 +}
 +
 +module Base {
 +  contains Main, A, B;
 +  exhibits from Jps {
 +      void JP(): call(* print*(..));
 +  }
 +}
 +
 +class Main {
 +        public static void main(String args[]) {
 +                new A().foo();
 +        }
 +}
 +
 +class B extends A {
 + public void foo() {
 + //some other code here
 + super.foo();
 + }
 +}
 +
 +class A {
 + public void foo() {
 + System.out.println("foo");
 + }
 +}
 +
 +module Aspects {
 +  contains Asp;
 +}
 +
 +aspect Asp {
 + after(): Jps.JP() {
 + new B().foo();
 + }
 +}
 +</code>
 +
 +Similar for the case with the "use" relationship.
 +
 +<code>
 +xpi Jps {
 +   joinpointtype void JP();
 +}
 +
 +
 +module Base {
 +  contains A, Util;
 +  exhibits void JP() : call(* print*(..));
 +}
 +
 +class A {
 + public static void main(String args[]) {
 + Util.print("Hello");;
 + }
 +}
 +
 +class Util {
 + public static void print(String s) {
 + System.out.println(s);
 + }
 +}
 +
 +module Aspect {
 +  contains Asp;
 +}
 +
 +aspect Asp {
 + after JP() {
 + Util.print(" World");
 + }
 +}
 +
 +</code>