Re: Singleton - Whether Cloneable overrides Singleton

From:

"Oliver Wong" <owong@castortech.com>

Newsgroups:

comp.lang.java.programmer

Date:

Mon, 26 Mar 2007 16:26:55 -0400

Message-ID:

<pUWNh.23803$ep6.300624@wagner.videotron.net>

"Proton Projects - Moin" <mohd.mohideen@gmail.com> wrote in message
news:1174891407.797380.236870@e65g2000hsc.googlegroups.com...

Hi all,

public class ChummaEx implements Cloneable
{
   private static ChummaEx moin = null;
   private String mName = null;
   private ChummaEx()
   {}

[Rest of the code snipped]

}

[...]

SIngleton has the functionality to create only instance...I was trying
to beak the singleton behavior and after a long research i achieved it
by using the Cloneable interface...

    There are easier ways to "break" singleton behaviour. For example:

public class ChummaEx {
  private static ChummaEx moin = null;
  private String mName = null;
  public ChummaEx()
  {}
[Rest of the code snipped]
}

My Questions are:
1. Whether the singleton behavior is overriden by the Cloneable
behavior
2. By implementing the Cloneable interface, how to retain the
Singleton behavior...
3. I tried to use the final key at some place to retain the singleton
behavior....but i failed.
4. Some group mates might have a question in their mind, why i have
used the Cloneable interface....as i already told, i was doing some
research over the singleton...

    Decide whether you want your class to be a Singleton or not.

    If you do: Do not "break" the singleton behaviour. That is: do not
provide a public constructor; do not implement cloneable; do not provide a
factory method which returns lots of different instances, etc.

    If you don't: Do not worry if you "break" the singleton behaviour.

    - Oliver