OnJava8-Examples/generics/PrimitiveGenericTest.java

// generics/PrimitiveGenericTest.java
// (c)2016 MindView LLC: see Copyright.txt
// We make no guarantees that this code is fit for any purpose.
// Visit http://mindviewinc.com/Books/OnJava/ for more book information.
import onjava.*;
import java.util.*;
import java.util.function.*;

// Fill an array using a generator:
interface FillArray {
  static <T> T[] fill(T[] a, Supplier<T> gen) {
    for(int i = 0; i < a.length; i++)
      a[i] = gen.get();
    return a;
  }
  static int[] fill(int[] a, IntSupplier gen) {
    for(int i = 0; i < a.length; i++)
      a[i] = gen.getAsInt();
    return a;
  }
  static long[] fill(long[] a, LongSupplier gen) {
    for(int i = 0; i < a.length; i++)
      a[i] = gen.getAsLong();
    return a;
  }
  static double[] fill(double[] a, DoubleSupplier gen) {
    for(int i = 0; i < a.length; i++)
      a[i] = gen.getAsDouble();
    return a;
  }
}

public class PrimitiveGenericTest {
  public static void main(String[] args) {
    String[] strings = FillArray.fill(
      new String[5], new Rand.String(9));
    System.out.println(Arrays.toString(strings));
    int[] integers = FillArray.fill(
      new int[9], new Rand.int_());
    System.out.println(Arrays.toString(integers));
  }
}
/* Output:
[YNzbrnyGc, FOWZnTcQr, GseGZMmJM, RoEsuEcUO, neOEdLsmw]
[8689, 7185, 6992, 5746, 3976, 2447, 5368, 1854, 1395]
*/