Question 1.1:
====================================================

aspect traversal1 {
  void A. t() {
      b.t(); c.t();
  }

  void B.t() {
    d.t(); e.t();
  }
  void C.t() {}
  void D.t() {
     System.out.println(" in D-object direct ");
  }
  void E.t() {
     System.out.println(" in E-object direct ");
  }
}

aspect visitor {
  // advising traversal traversal1
  before() : execution(void D.t()) {
  // before() : call(void D.t()) { // does not work in general, 
				   // e.g., in A.c is a D
    System.out.println(" in D-object ");
  } 
  before() : execution(void E.t()) {
  // before() : call(void E.t()) {
    System.out.println(" in E-object ");
  } 
}

class A {
  B b;
  C c;
  A(B b, C c){ this.b = b; this.c = c;}
}

class B {
  D d;
  E e;
  B(D d, E e) {this.d = d; this.e = e;}
}

class C {
}

class D extends C {
}

class E extends C {
}

class Main {
  static public void main(String args[]) {
    A a_in = new A(new B(new D(), new E()), new D());
    a_in.t();
  }
}  


 in D-object 
 in D-object direct 
 in E-object 
 in E-object direct 
 in D-object 
 in D-object direct 

Question 1.2
============================================

// Plan:
// to capture crossings from one object to another,
// we rewrite the traversal so that a pointcut
//  call(void *.crossing*(..)) && this(s) && args(t)
// captures edge crossings. If t is a D, we print s.

aspect traversal1 {
  void A. t() {
      crossing_t_b(b); crossing_t_c(c) ;
  }
  void A.crossing_t_b(B b){b.t();}
  void A.crossing_t_c(C c){c.t();}

  void B.t() {
    crossing_t_d(d); crossing_t_e(e);
  }
  void B.crossing_t_d(D d){d.t();}
  void B.crossing_t_e(E e){e.t();}

//  void B.t() {
//    d.t(); e.t();
//  }
  void C.t() {}
  void D.t() {
     System.out.println(" in D-object direct ");
  }
  void E.t() {
     System.out.println(" in E-object direct ");
  }
}

aspect visitor {
  // advising traversal traversal1
  before() : execution(void D.t()) {
  // before() : call(void D.t()) {
    System.out.println(" in D-object ");
  } 
  before() : execution(void E.t()) {
  // before() : call(void E.t()) {
    System.out.println(" in E-object ");
  } 
  before() : call(void D.t()) {
    Object thiz = thisJoinPoint.getThis();
    Object target = thisJoinPoint.getTarget();
    System.out.println("target = " + target +
		       "this ="    + thiz);
  }
  pointcut crossing(Object s, Object t):
    call(void *.crossing*(..)) && this(s) && args(t);
  before(Object s, Object t) : crossing(s,t) {
    if (t instanceof D) { 
    System.out.println("target = " + t +
		       "source ="    + s);
    }
  }

}

class A {
  B b;
  C c;
  A(B b, C c){ this.b = b; this.c = c;}
}

class B {
  D d;
  E e;
  B(D d, E e) {this.d = d; this.e = e;}
}

class C {
}

class D extends C {
}

class E extends C {
}

class Main {
  static public void main(String args[]) {
    A a_in = new A(new B(new D(), new E()), new D());
    a_in.t();
  }
}  

output:


target = D@31f71asource =B@5601ea
target = D@31f71athis =B@5601ea
 in D-object 
 in D-object direct 
 in E-object 
 in E-object direct 
target = D@7259dasource =A@6930e2
 in D-object 
 in D-object direct 


Ryan Culpepper's solution:

aspect FoundD{
  Object caller;
  void around():call(void *.t()) {
    caller = thisJoinPoint.getThis();
    proceed();
  }
  void around() : execution(void D.t()) {
    System.out.println(" ryan " + thisJoinPoint.getThis());
    System.out.println(" ryan " + caller);
  }
}


Question 2:
======================================

aspect AddMain {
 after():call(static void main(..)){
   System.out.println(" done ");
 }
}

Question 3:

essay question

Question 4:
====================================================
1: Execution
2: Execution
3: thisJoinPoint.getArgs
4: argument
5: thisJoinPoint.getThis
6: receiver
7: NOTHING
8: Execution
9: ConstructorCall
10: NOTHING
11: NOTHING
12: newLocalObj
13: local
14: Execution
15: MethodCall
16: NOTHING
17: 
 if(returnVal != null){
       if(thisJoinPoint.getThis() == thisJoinPoint.getTarget()){
	       add(returnVal, local + JPUtil.at(thisJoinPoint));
		     }
18: remove // in:

//      suppliers.add( ArgumentBin.aspectOf() );
//      suppliers.add( LocallyConstructedBin.aspectOf() );
//      suppliers.add( ReturnValueBin.aspectOf() );