/*
 *     file: ArrayDemo.java
 *  package: oreilly.hcj.reflection
 *
 * This software is granted under the terms of the Common Public License,
 * CPL, which may be found at the following URL:
 * http://www-124.ibm.com/developerworks/oss/CPLv1.0.htm
 *
 * Copyright(c) 2003-2005 by the authors indicated in the @author tags.
 * All Rights are Reserved by the various authors.
 *
########## DO NOT EDIT ABOVE THIS LINE ########## */

package oreilly.hcj.reflection;

import java.lang.reflect.Array;

/**  
 * Demonstrates the use of the Array class.
 *
 * @author <a href=mailto:kraythe@arcor.de>Robert Simmons jr. (kraythe)</a>
 * @version $Revision$
 */
public class ArrayDemo {
	/** 
	 * Copy an array and return the copy.
	 *
	 * @param input The array to copy.
	 *
	 * @return The coppied array.
	 *
	 * @throws IllegalArgumentException If input is not an array.
	 */
	public static Object copyArray(final Object input) {
		final Class type = input.getClass();
		if (!type.isArray()) {
			throw new IllegalArgumentException();
		}
		final int length = Array.getLength(input);
		final Class componentType = type.getComponentType();

		final Object result = Array.newInstance(componentType, length);
		for (int idx = 0; idx < length; idx++) {
			Array.set(result, idx, Array.get(input, idx));
		}
		return result;
	}

	/** 
	 * Run the demo.
	 *
	 * @param args Command line arguments (ignored).
	 */
	public static void main(final String[] args) {
		try {
			int[] x = new int[] { 2, 3, 8, 7, 5 };
			char[] y = new char[] { 'a', 'z', 'e' };
			String[] z = new String[] { "Jim", "John", "Joe" };

			System.out.println(" -- x and y --");
			outputArrays(x, y);

			System.out.println(" -- x and copy of x --");
			outputArrays(x, copyArray(x));

			System.out.println(" -- y and copy of y --");
			outputArrays(y, copyArray(y));

			System.out.println(" -- z and copy of z --");
			outputArrays(z, copyArray(z));
		} catch (final Exception ex) {
			ex.printStackTrace();
		}
	}

	/** 
	 * Print out 2 arrays in columnar format.
	 *
	 * @param first The array for the first column.
	 * @param second The array for the second column.
	 *
	 * @throws IllegalArgumentException __UNDOCUMENTED__
	 */
	public static void outputArrays(final Object first, final Object second) {
		if (!first.getClass()
		          .isArray()) {
			throw new IllegalArgumentException("first is not an array.");
		}
		if (!second.getClass()
		           .isArray()) {
			throw new IllegalArgumentException("second is not an array.");
		}

		final int lengthFirst = Array.getLength(first);
		final int lengthSecond = Array.getLength(second);
		final int length = Math.max(lengthFirst, lengthSecond);

		for (int idx = 0; idx < length; idx++) {
			System.out.print("[" + idx + "]\t");
			if (idx < lengthFirst) {
				System.out.print(Array.get(first, idx) + "\t\t");
			} else {
				System.out.print("\t\t");
			}
			if (idx < lengthSecond) {
				System.out.print(Array.get(second, idx) + "\t");
			}
			System.out.println();
		}
	}
}

/* ########## End of File ########## */