COM 3362			Aspect-Oriented Software Development
				Karl Lieberherr
				Winter 2002
Homework 7

Integrating Demeter into AspectJ using Aspect-Oriented Programming

prepared with John Sung

Due Feb 26, 2002

So far we have integrated traversals into AspectJ
by translating traversal specifications into introductions.

We can program the visitors using AspectJ syntax but this
leads to verbose code. Therefore we would like to generate the
pointcuts and advice from the visitor notation.

The best way to add visitors to AspectJ without modifying the 
AspectJ tool is to add a visitor declaration language to the T
language we introduced earlier.
We want to do this with minimal extension to 
AspectJ and by 100% Java using the Java interface language.

aspect Traversals {
  declare traversal t1 : "from Basket to *";
  declare traversal t2 : "from Basket to Weight";
}

becomes:

aspect Traversals {
  declare visitors : Visitor1Interface, Visitor2Interface;
  declare traversal t1(Visitor1Interface) : "from Basket to *";
  declare traversal t2(Visitor1Interface) : "from Basket to Weight";
}

This means that in one of the Java files there must be an
interface like:

  interface Visitor1Interface {
    void before(A a);
    void after(B host);
    void after(C host);
    void start();
    void finish();
  }

This produces a traversal method void t2(Visitor1Interface v1)
for Basket-objects.

AspectJ is used as follows:

ajc *.java 			// first compilation
java Main > traversals.java ... // first run (stopped prematurely)
ajc *.java 			// second compilation
java Main ... 			//second run

Information about the interfaces can be collected in the first run using
Java reflection.

http://java.sun.com/docs/books/tutorial/reflect/class/isInterface.html


Edge methods:
=============

Reuse the design from assignment 4, part 3c and also translate edge methods to
AspectJ syntax.


Around methods:
===============

Also add around methods for both nodes and edges to your tool.
They have an additional argument of type SubTraversal
with a method apply() and a method apply(String s).
apply continues the traversal and apply("edgeName") continues
the traversal on edge "edgeName".

See:

/proj/adaptive2/course/com1205/w02/project/
for more information