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Groups > comp.lang.java.programmer > #30584

Re: a question about factory method

Newsgroups comp.lang.java.programmer
Date 2014-12-18 08:04 -0800
References <ff7f0941-582f-4a6f-83fd-2fa71434ff46@googlegroups.com> <m6usaq$6bg$1@dont-email.me>
Message-ID <ae5dcc85-b23a-4ee3-94b3-350e585f502d@googlegroups.com> (permalink)
Subject Re: a question about factory method
From John <xsli2@yahoo.com>

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Thank you all for replies.

Can you elaborate a little more about
 Its getInstance() methods usually return a GregorianCalendar instance,
but could (if Locales and so on were set up) return an instance of
MayanCalendar or JulianCalendar or BabylonianCalendar or whatever:
Classes whose names, whose very existence, might not have been known
when the calling code was written.

My guess is something like below. Is that correct? Thank you very much.

public class Calendar {

  /**
  * Static factory method returns an object of this class or subclass. for choice: 1 for GregorianCalendar, 2 for MayanCalendar , 3 for JulianCalendar
  */
  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;
    }
   
  }

...
}

How can I make it return MayanCalendar or JulianCalendar?

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Thread

a question about factory method John <xsli2@yahoo.com> - 2014-12-18 05:57 -0800
  Re: a question about factory method Robert Klemme <shortcutter@googlemail.com> - 2014-12-18 15:28 +0100
  Re: a question about factory method Silvio <silvio@internet.com> - 2014-12-18 15:43 +0100
  Re: a question about factory method Eric Sosman <esosman@comcast-dot-net.invalid> - 2014-12-18 10:37 -0500
    Re: a question about factory method John <xsli2@yahoo.com> - 2014-12-18 08:04 -0800
      Re: a question about factory method Eric Sosman <esosman@comcast-dot-net.invalid> - 2014-12-18 12:04 -0500
        Re: a question about factory method John <xsli2@yahoo.com> - 2014-12-18 10:43 -0800
          Re: a question about factory method Eric Sosman <esosman@comcast-dot-net.invalid> - 2014-12-18 14:24 -0500
            Re: a question about factory method Robert Klemme <shortcutter@googlemail.com> - 2014-12-19 01:39 +0100
  Re: a question about factory method Roedy Green <see_website@mindprod.com.invalid> - 2014-12-18 13:43 -0800

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