ArrayDemo.java Source code

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Here is the source code for ArrayDemo.java

Source

/*
 *     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 ########## */

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 ########## */