IntArrays.java

// Concrete implementation built atop skeletal implementation - Page83
package effectivejava.chapter4.item18;

import java.util.AbstractList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;

public class IntArrays {
	static List<Integer> intArrayAsList(final int[] a) {
		if (a == null)
			throw new NullPointerException();

		return new AbstractList<Integer>() {
			public Integer get(int i) {
				return a[i]; // Autoboxing (Item 5)
			}

			@Override
			public Integer set(int i, Integer val) {
				int oldVal = a[i];
				a[i] = val; // Auto-unboxing
				return oldVal; // Autoboxing
			}

			public int size() {
				return a.length;
			}
		};
	}

	public static void main(String[] args) {
		int[] a = new int[10];
		for (int i = 0; i < a.length; i++)
			a[i] = i;
		List<Integer> list = intArrayAsList(a);

		Collections.shuffle(list);
		System.out.println(list);
		
		HashMap h = null;
	}
}