OnJava8-Examples/arrays/IceCream.java

// arrays/IceCream.java
// (c)2016 MindView LLC: see Copyright.txt
// We make no guarantees that this code is fit for any purpose.
// Visit http://OnJava8.com for more book information.
// Returning arrays from methods
import java.util.*;
import static onjava.ArrayShow.*;

public class IceCream {
  private static SplittableRandom rand =
    new SplittableRandom(47);
  static final String[] FLAVORS = {
    "Chocolate", "Strawberry", "Vanilla Fudge Swirl",
    "Mint Chip", "Mocha Almond Fudge", "Rum Raisin",
    "Praline Cream", "Mud Pie"
  };
  public static String[] flavorSet(int n) {
    if(n > FLAVORS.length)
      throw new IllegalArgumentException("Set too big");
    String[] results = new String[n];
    boolean[] picked = new boolean[FLAVORS.length];
    for(int i = 0; i < n; i++) {
      int t;
      do
        t = rand.nextInt(FLAVORS.length);
      while(picked[t]);
      results[i] = FLAVORS[t];
      picked[t] = true;
    }
    return results;
  }
  public static void main(String[] args) {
    for(int i = 0; i < 7; i++)
      show(flavorSet(3));
  }
}
/* Output:
[Praline Cream, Mint Chip, Vanilla Fudge Swirl]
[Strawberry, Vanilla Fudge Swirl, Mud Pie]
[Chocolate, Strawberry, Vanilla Fudge Swirl]
[Rum Raisin, Praline Cream, Chocolate]
[Mint Chip, Rum Raisin, Mocha Almond Fudge]
[Mocha Almond Fudge, Mud Pie, Vanilla Fudge Swirl]
[Mocha Almond Fudge, Mud Pie, Mint Chip]
*/