CSC/ECE 517 Summer 2008/wiki1 5 a5

Introduction

Ruby has hooks that allows trapping a certain event (e.g., object creation) and running a particular code sequence whenever the event occurs. There's no comparable facility in Java. But both Ruby and Java have support for aspect-oriented programming (AspectR and AspectJ, respectively). What's the difference between simply providing hooks, and supporting full AOP, and why is it more convenient to program this way in Ruby than Java? Give a few code sequences to justify your conclusions.

Hooks

There is a strong desired from developers to have control on object life cycle. They would like to know when an object is created or destroyed, or some specific method is executed. They would like to monitor what application is doing inside and look for possibility to change application behavior or add new functionality without making big changes in object model.

Hooks Implementation

Most of dynamic languages provide some ways to execute custom code at different steps of object life cycle. Most of them built this functionality as part of language design. They use interceptor design pattern {} as implementation guideline.