John J. Sung

TA Consulting

Motivation for TraversalJ

• KL Enterprises identified AOP

• Enter into the AOP market early

• Add value by adding traversals to Java

• Contract COM 1205 Inc.

• TA Consulting Recommendations

High-Level System Overview

traversal.trv TraversalJ

traversal.java

AspectJtraversal.class

System Components

• traversal.trv – TraversalJ file with class graph and traversal declarations

• TraversalJ – DemeterJ program by COM1205

• traversal.java – Traversal code in AspectJ• AspectJ – Aspect Oriented Programming

Tool

TraversalJ Overview

• Implement using DemterJ– class dictionary– traversals

• Obtain Class Graph using AspectJ & DJ– CreateClassGraph.java

• Output traversal java code– AspectJTraversal.java

TraversalJ System

traversal.trv

COM1205Middle-ware

CreateClassGraph

AspectJTraversal traversal.java

Main

ClassGraphEvent(args, cg)

AspectJTraversal

• Java code to translate class graph + strategy into AspectJ code

• Processes DJ classes to do most of the work

TraversalJ Syntax

• ClassGraph Specification– ClassGraph cgvar;– ClassGraph cgvar = new ClassGraph(cg,

“strategy”);

• Traversal Specification– declare traversal tvar : “strategy”;– declare traversal tvar(cgvar) : “strategy”;

TraversalJ Syntax

• Traversal Aspect Specification– aspect aspectName { – class graph declaration;– traversal declaration;– }

TraversalJ Syntax Example

aspect MyTraversal {

ClassGraph defaultCG;

ClassGraph cg1 = new ClassGraph(defaultCG, “from * bypassing {java.lang.String} to

*”);

declare traversal t1: “from CompoundFile to SimpleFile”;

declare traversal t2(cg1): “from CompoundFile to *”;}

Graphs and Traversals?

• Need to obtain Default Class Graph

• Keep track of declared Class Graphs

• Process traversal with specific Class Graph

TraversalJ System

traversal.trv

COM1205Middle-ware

CreateClassGraph

AspectJTraversal traversal.java

Main

ClassGraphEvent(args, cg)

ClassGraphListener/Factory

• ClassGraphListenerFactory– Need a way to obtain an instance of

Middle-ware code– ClassGraphListener getNew();

• ClassGraphListener– need a way to pass ClassGraph and

arguments– abstract void ClassGraphEvent(String []

args, ClassGraph cg);

ClassGraphListener/Factory

ClassGraphFactory

ClassGraphListener

MyListener

getNew()

new MyListener()

ClassGraphListener

CreateClassGraph

ClassGraphListener/Factory

ClassGraphListener

MyListener

CreateClassGraph

ClassGraphEvent(args, cg)

Some Other Code

.prj File

• Copy CreateClassGraph.java and AspectJTravearsal.java into a directory

• Add the directory for the JAVADIR option in .prj file

• COMPILER = ajc• TEST_ARGS = -d trav some.trv• TEST_INPUT = some.trv

Testing TraversalJ

• Create some traversal file that implements a traversal that’s used in TraversalJ.

• Generate the .java file into a directory• Add the directory for JAVADIRS• Add code to call the traversal method

in .beh files.• Compile with traversal code and test

Fun with Recursion

traversal.trv

COM1205Middle-ware

DemeterJ

traversal.java

AspectJ

TraversalJ

Debugging Strategy

• Traversals– You can use DJ to output traversal graphs– Look for error messages from demeterj

• General Debugging– have some variable debug to turn on debug

output

• AspectJTraversal– debug : outputs processing information– addPrintingAdvice : Outputs code for printing

traversal method calls

TraversalJ Project Phases

• Phase1 – Generate Class Dictionary for the traversal language

• Phase 2 – Implement –d directory option, basic traversal with default Class Graph

• Phase 3 – Implement Class Graph declaration and definition

• Phase 4 – Test code by generating a traversal used in TraversalJ

Project Submission

• Use ~jser/submit-proj

• README – How to compile your program– How to generate traversal code– How to test traversal code

• Due Date: March 8, 2002

Project Write Up

• Class Graph UML Diagram

• Document Traversals

• Document Testing of Traversal Code

• Evaluate software design and usefulness of TraversalJ

• Drop it off in class or mail box of TA

• Due Date: March 11, 2002

Questions?

• com1205-grader@ccs.neu.edu

• Reaches both KLE and TAC.• http://www.ccs.neu.edu/home/lieber/com3362/w02/

CCS_AspectJ_Usage.html