ArrayGrowTest

gistfile1.java

package tp2;

/*
 * Cay S. Horstmann & Gary Cornell, Core Java
 * Published By Sun Microsystems Press/Prentice-Hall
 * Copyright (C) 1997 Sun Microsystems Inc.
 * All Rights Reserved.
 *
 * Permission to use, copy, modify, and distribute this
 * software and its documentation for NON-COMMERCIAL purposes
 * and without fee is hereby granted provided that this
 * copyright notice appears in all copies.
 *
 * THE AUTHORS AND PUBLISHER MAKE NO REPRESENTATIONS OR
 * WARRANTIES ABOUT THE SUITABILITY OF THE SOFTWARE, EITHER
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
 * PARTICULAR PURPOSE, OR NON-INFRINGEMENT. THE AUTHORS
 * AND PUBLISHER SHALL NOT BE LIABLE FOR ANY DAMAGES SUFFERED
 * BY LICENSEE AS A RESULT OF USING, MODIFYING OR DISTRIBUTING
 * THIS SOFTWARE OR ITS DERIVATIVES.
 */

/**
 * @version 1.00 11 Mar 1997
 * @author Cay Horstmann
 * @author Filip Krikava - few modifications for the purpose of the SE Lab
 */

import java.lang.reflect.*;
import java.util.Arrays;

public class ArrayGrowTest {
	
	/**
	 * Just a sample class
	 *
	 */
	static class Personne {
		private String nom;

		public Personne(String nom) {
			this.nom = nom;
		}

		public String toString() {
			return nom;
		}
	}

	public static void main(String[] args) {
		int[] a = { 1, 2, 3 };
		
		Personne[] b = { new Personne("Maurice Chombier"),
				new Personne("Francois Pignon") };

                // TODO: uncomment once goodArrayGrow is finished
		// a = (int[]) goodArrayGrow(a);
		// System.out.println(Arrays.toString(a));
		// b = (Personne[]) goodArrayGrow(b);
		// System.out.println(Arrays.toString(b));

		System.out.println(Arrays.toString(badArrayGrow(b)));

		System.out.println("The following call will generate an exception.");
		b = (Personne[]) badArrayGrow(b);
	}

	// an intuitive solution that does not work
	// there is a casting problem between Object[] and T[]
	// since it creates new Object[] not new T[]
	// where T is some type
	private static Object[] badArrayGrow(Object[] a) {
		int newLength = a.length * 2;
		Object[] newArray = new Object[newLength];
		System.arraycopy(a, 0, newArray, 0, a.length);
		return newArray;
	}

	// in order to make it work with priminitive types like (int[]) the
	// parameter type has to be Object
	private static Object goodArrayGrow(Object a) {
		// TODO: write the code that grows the array by 2
		return null;
	}
}