General talk about software patterns

[Jesús Alonso <kenchoweb AT hotmail.com>]

Thanks for your help. I understand a little better this pattern.

About the book, can't have access to it right now, and I would have to buy 
it for just that pattern...

Thanks again for your help


> Hi,
>
> this pattern solves the problem of how a series of operations can all 
> contribute to a collection of results. You could of course have the 
> operations return a collection and accumulate the results in the loop that 
> calls them, but in e.g. Java methods can have only one return value and 
> that may be "in use" for other things.
>
> A typical use is the gathering of messages, especially error messages. The 
> return value of the operations is often in use for the actual "business" 
> part of the operations, and the use of exceptions would mean that every 
> operation can contribute at most one message.
>
> Therefore: pass a collection to each operation so that it can contribute 
> all the messages. This parameter "collects" the messages, hence the name of 
> the pattern. It is useful e.g. for collecting messages to be displayed in a 
> UI.
>
> It is documented in Kent Beck's "Smalltalk Best Practices" book, wich 
> contains a lot of very helpful patterns that are applicable to other 
> languages as well.
>
> - Arno
>
>
>
> Jesús Alonso wrote:
> > Hello.
> >
> > I need information about the Collecting Parameter design pattern, but all 
> > I could find was the info in this page: 
> > http://c2.com/cgi/wiki?CollectingParameter
> >
> > The fact is that the information given there about the pattern isn't 
> > enough for me to understand very well the pattern.
> > I would find helpful any information about what this pattern does exactly, 
> > some examples, and maybe a concrete context where it could be applied 
> > successfully and why.
> >
> > Thanks in advance.
> >
> > Best regards,
> >  Jesús Alonso
> >
> >
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