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  1.  
  2. import java.util.ArrayList;
  3. import java.util.List;
  4.  
  5. class Singleton {
  6.  
  7.  
  8.     private final static int N = 3;
  9.     private static int counter = 0;
  10.     private static List<Singleton> instances = new ArrayList<Singleton>();
  11.     private int id;
  12.  
  13.     private Singleton (int id) {
  14.         this.id = id;
  15.     }
  16.  
  17.     public static Singleton getInstance () {
  18.         int instanceId = counter % N;
  19.         if (instances.size() < instanceId + 1) {
  20.             instances.add(new Singleton(instanceId));
  21.         }
  22.         counter++;
  23.         return instances.get(instanceId);
  24.     }
  25.  
  26.     public String toString () {
  27.         return "Singleton(" + id + ")";
  28.     }
  29.  
  30. }
  31.  
  32.  
  33. class SingletonTest {
  34.  
  35.  
  36.     public static void main (String[] args) {
  37.         System.out.println(Singleton.getInstance());
  38.         System.out.println(Singleton.getInstance());
  39.         System.out.println(Singleton.getInstance());
  40.         System.out.println(Singleton.getInstance());
  41.         System.out.println(Singleton.getInstance());
  42.         System.out.println(Singleton.getInstance());
  43.         System.out.println(Singleton.getInstance());
  44.     }
  45.  
  46. }
  47.  
  48.  
  49.  
  50.  
Success #stdin #stdout 0.07s 380160KB
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Standard input is empty
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Singleton(0)
Singleton(1)
Singleton(2)
Singleton(0)
Singleton(1)
Singleton(2)
Singleton(0)
https://ideone.com/6NQJ1o
language:
Java (HotSpot 12)
created:
11 years ago
visibility:
public

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