Subject: Doubts on design patterns

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Subject: Doubts on design patterns

Subject: Doubts on design patterns

2004-04-28 - By Sergey Beryozkin

Back

Reply: 1 2 3 4 5 6 7 8

Hi Ben, others

Lets consider servlet filter chains. IMHO they may exhibit the
characterstics of both patterns. A given filter decorates the request and/or
response in most cases by pre and/or post processing it. When a filter
blocks a request, then it acts as a final handler in the chain, as it
assumes a responsibility for the actual handling of the request.
Would you agree ?
Thanks
Sergey Beryozkin

> 4) what is main difference between Decorator and Chain Of Responsibility?

They are not really comparable as they are completely different - think;
"the
difference between a banana and a melon". The Chain of Responsibility allows
you to use a bunch of objects to deal with a request only if the object is
responsible for the request. The Decorator allows you to add additional
functionality to an object dynamically.

You can always visit www.javacoder.net and see the GoF patterns
implementation there.

HTH

Ben

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