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From José Antonio Pérez Testa <>
Subject Re: Collections HowTo
Date Wed, 18 Aug 2004 15:08:07 GMT
All that concepts are imported into java from Functional Programming 
Languages such as Prolog or CAML.

IMHO they give a hand when working with Collections extracting the 
process out of the loop.
For example, if you want to add all the elements of a List you only have 
to define the add process and delegate to the Functor the loop itself.
When you have a list of  some type and need a list of some other type 
objects you only define the Transformer,
and if you want to select objects from a Collection based on some 
criteria, you have to code the criteria , pass it to a Functor and 
you'll have in return a new list with ONLY those objects.

Is another just another look into programming!

Leandro Rodrigo Saad Cruz wrote:

>What is the concept behind Functor/Predicate/Transformer ?
>On Wed, 2004-08-18 at 10:44, matthew.hawthorne wrote:
>>Leandro Rodrigo Saad Cruz wrote:
>>>Hi all. Any directions on how to use Functors and Predicates ?
>>Hmm... maybe read the Javadoc?
>>It's hard to respond to such a vague question, do you have a more 
>>specific problem you're trying to solve?
>>Basically, there are methods in CollectionUtils that take a collection 
>>and a Functor/Predicate/Transformer as a parameter.
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