Java开发网 - 请教:如何才能保持一个类只有一个实例对像呀?

Topic: 请教:如何才能保持一个类只有一个实例对像呀?

1.请教:如何才能保持一个类只有一个实例对像呀?	Copy to clipboard
Posted by: naughty009 Posted on: 2005-07-07 17:39 请教:如何才能保持一个类只有一个实例对像呀?高手帮帮忙呀~!

2.Re:请教:如何才能保持一个类只有一个实例对像呀? [Re: naughty009]	Copy to clipboard
Posted by: ww1ww1 Posted on: 2005-07-07 19:52 感觉是这样： constructor 用static 来修饰 class OnlyOne { static OnlyOne() { } } Is that right?

3.Re:请教:如何才能保持一个类只有一个实例对像呀? [Re: naughty009]	Copy to clipboard
Posted by: naughty009 Posted on: 2005-07-07 20:59 哈~!那就奇了好像还可以这样吧 OnlyOne o1=new OnlyOne() OnlyOne o2=new OnlyOne() OnlyOne o3=new OnlyOne() 还是可以实例N个对像吧~

4.Re:请教:如何才能保持一个类只有一个实例对像呀? [Re: naughty009]	Copy to clipboard
Posted by: ww1ww1 Posted on: 2005-07-07 21:08 OnlyOne o1=new OnlyOne OnlyOne o2=new OnlyOne OnlyOne o3=new OnlyOne 这个我怎么看上去就奇。自己随便找本书看看，不要是盗版的（可能有印刷错误）。这样的东西也写得出来。。。faint

5.Re:请教:如何才能保持一个类只有一个实例对象呀? [Re: naughty009]	Copy to clipboard
Posted by: why Posted on: 2005-07-07 21:12 对象 search for Singleton in this forum (Design Patterns board)

6.Re:请教:如何才能保持一个类只有一个实例对像呀? [Re: naughty009]	Copy to clipboard
Posted by: ww1ww1 Posted on: 2005-07-07 22:54 还挺复杂的，看来要继续好好学习啦

7.Re:请教:如何才能保持一个类只有一个实例对像呀? [Re: naughty009]

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Posted by: ranchgirl
Posted on: 2005-07-08 06:37

Give you an example, such as President, one country should have one, I guess. Now, you use singleton pattern is justified.


// Only one President in one country
// Singleton usage is justified
public class President {
   private static President currPresident = null;
   
   private President() {
      // Exists only to defeat instantiation.
   }
   public static President getInstance() {
      if (currPresident == null) {
         currPresident = new President();
      }
      return currPresident;
   }
}

When you need a President, you call President.getInstance(). If we have a President, the current President is returned, otherwise, create (vote) a new President. Smile

Now, your purpose "一个类只有一个实例对像" President is reached. Big Smile

8.Re:请教:如何才能保持一个类只有一个实例对像呀? [Re: naughty009]	Copy to clipboard
Posted by: naughty009 Posted on: 2005-07-08 10:17 哈~!谢谢楼上~~~~

9.Re:请教:如何才能保持一个类只有一个实例对像呀? [Re: naughty009]	Copy to clipboard
Posted by: why Posted on: 2005-07-08 10:43 naughty009 wrote: 哈~!谢谢楼上~~~~ sigh... you really should have searched on this forum before you posted this question.

10.Re:请教:如何才能保持一个类只有一个实例对像呀? [Re: naughty009]	Copy to clipboard
Posted by: naughty009 Posted on: 2005-07-08 16:56 I have found everywhere on this forum,but none of this question. thanks a lot.

11.Re:请教:如何才能保持一个类只有一个实例对像呀? [Re: naughty009]	Copy to clipboard
Posted by: why Posted on: 2005-07-08 23:25 naughty009 wrote: I have found everywhere on this forum,but none of this question. thanks a lot. Everywhere?!?! Lair! Bullshit! search with keyword : singleton Singleton Pattern 的java实现（代码） http://www.cjsdn.net/post/view?bid=17&id=43923

12.Re:请教:如何才能保持一个类只有一个实例对像呀? [Re: why]

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Posted by: ranchgirl
Posted on: 2005-07-08 23:33

why wrote:
Everywhere?!?!
Lair!
Bullshit!
search with keyword : singleton
Singleton Pattern 的java实现（代码）
http://www.cjsdn.net/post/view?bid=17&id=43923

WHY, you have a bad mode today, I guess. Smile

I think you have been unreasonable with naughty009.

What if he had never heard the word "singleton", how did he know to search for "singleton"?

Put yourself in his/her shoes might help...

13.Re:请教:如何才能保持一个类只有一个实例对像呀? [Re: gongshi]

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Posted by: why
Posted on: 2005-07-09 00:21

gongshi wrote:
I think you have been unreasonable with naughty009.

What if he had never heard the word "singleton", how did he know to search for "singleton"?

Put yourself in his/her shoes might help...

Please take a look at my post on this topic, I wrote:
search for Singleton in this forum (Design Patterns board)

Yes, I'm in a bad mood, my back has been hurting me duing the past few days. But I'm mad because I am very disappointed with the newbies in general.

14.Re:请教:如何才能保持一个类只有一个实例对像呀? [Re: naughty009]	Copy to clipboard
Posted by: naughty009 Posted on: 2005-07-09 09:56 It doesn't matter , please don't responsible for why You are my god.

15.Re:请教:如何才能保持一个类只有一个实例对像呀? [Re: naughty009]	Copy to clipboard
Posted by: why Posted on: 2005-07-09 11:12 naughty009 wrote: It doesn't matter , please don't responsible for why You are my god. Did you read my post (the fifth one of this topic) when you wrote: I have found everywhere on this forum,but none of this question. What had you searched? EVERYWHERE?!?!?!

16.Re:请教:如何才能保持一个类只有一个实例对像呀? [Re: naughty009]	Copy to clipboard
Posted by: johnyq Posted on: 2005-07-09 14:06 这个是单子的模型用到其实就是 static private 几个关键字的使用