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  1. import java.util.Arrays;
  2. import java.util.List;
  3. import java.util.Random;
  4. import java.util.stream.Collectors;
  5. import java.util.stream.IntStream;
  6.  
  7. class Main
  8. {
  9. 	static class RandomMethod {
  10.         private final Runnable method;
  11.         private final int chance;
  12.  
  13.         RandomMethod(Runnable method, int chance){
  14.             this.method = method;
  15.             this.chance = chance;
  16.         }
  17.  
  18.         public int getChance() { return chance; }
  19.         public void run() { method.run(); }
  20.     }
  21.  
  22.     static class MethodChooser {
  23.         private final List<RandomMethod> methods;
  24.         private final int total;
  25.  
  26.         MethodChooser(final List<RandomMethod> methods) {
  27.             this.methods = methods;
  28.             this.total = methods.stream().collect(Collectors.summingInt(RandomMethod::getChance));
  29.         }
  30.  
  31.         public void chooseMethod() {
  32.             final Random random = new Random();
  33.             final int choice = random.nextInt(total);
  34.  
  35.             int count = 0;
  36.             for (final RandomMethod method : methods)
  37.             {
  38.                 count += method.getChance();
  39.                 if (choice < count) {
  40.                     method.run();
  41.                     return;
  42.                 }
  43.             }
  44.         }
  45.     }
  46.  
  47.     private static void aaa() { System.out.println("a"); }
  48.     private static void bbb() { System.out.println("b"); }
  49.     private static void ccc() { System.out.println("c"); }
  50.  
  51.     public static void main(String[] args) {
  52.         MethodChooser chooser = new MethodChooser(Arrays.asList(
  53.             new RandomMethod(Main::aaa, 1),
  54.             new RandomMethod(Main::bbb, 3),
  55.             new RandomMethod(Main::ccc, 1)
  56.         ));
  57.  
  58.         IntStream.range(0, 100).forEach(
  59.             i -> chooser.chooseMethod()
  60.         );
  61.     }
  62. }
Success #stdin #stdout 0.16s 4386816KB
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https://ideone.com/y1mzDV
language:
Java (HotSpot 12)
created:
6 years ago
visibility:
public

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