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From: Robert Klemme <shortcutter@googlemail.com>
Newsgroups: comp.lang.java.programmer
Subject: Re: a question about factory method
Date: Fri, 19 Dec 2014 01:39:25 +0100
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Xref: csiph.com comp.lang.java.programmer:30591

On 18.12.2014 20:24, Eric Sosman wrote:

>      As to *how* a factory method might choose which of several classes
> to return, you already illustrated one way (paraphrased):
>
>      public static Calendar getInstance(Date aDate, int choice) {
>          if (choice == 1) {
>              ... //return a GregorianCalendar object
>          } else if (choice == 2) {
>              ... //return a MayanCalendar object
>          } else if (choice == 3) {
>              ... //return a JulianCalendar object
>          } else {
>              return null;
>          }
>      }
>
> To me, this doesn't seem a huge advantage: The caller who writes
> `getInstance(date, 2)' could just as easily write `new MayanCalendar()'
> with about the same effect.

The crucial point is that the caller does not need to know the criteria 
when to create what type.  That _is_ a huge advantage.

Cheers

	robert


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