To: sjh@cs.brown.edu
Subject: abstract
Cc: sk@cs.brown.edu

Hi Susan:

enclosed is an abstract that fits better.

-- Karl

Title:
Better Separation of Crosscutting Concerns with Aspectual Components

Speaker:
Prof. Karl Lieberherr                         phone: (617) 373 2077 (office)
Northeastern University                       fax:   (617) 373 5121
College of Computer Science                   
161 Cullinane Hall                           
Boston, MA 02115-9959                       
My home page:        http://www.ccs.neu.edu/home/lieber   


Abstract:

Proper separation of concerns is still an interesting topic
in software development and in this talk 
we focus on traversal-related concerns and how to 
encapsulate them as reusable components.
Traversal related concerns involve 
a group of connected objects that we traverse and manipulate to 
implement a behavior. Traversal-related concerns cut 
across multiple classes and are 
very common. Following the ideas of Aspect-Oriented Programming (AOP), 
we would like to encapsulate a traversal-related concern into an aspect. 
Doing this in the straight-forward way leads to reduced scattering, but 
often results in an aspect that is tangled with accidental structural 
information. We notice a tradeoff between reducing scattering across 
classes and increasing tangling of structural information in the aspect.

We find a fundamental improvement to this tradeoff by using ideas from 
non-deterministic finite automata theory to often reduce simultaneously
both scattering and 
tangling. The well localized traversal-related aspects
are conceptually aspectual components and can be 
simulated in plain Java using basically three classes from the Java 
package DJ. We explain the basics of DJ and how you can better 
structure your Java programs using ideas from Aspectual Components.