    001/* ========================================================================
    002 * JCommon : a free general purpose class library for the Java(tm) platform
    003 * ========================================================================
    004 *
    005 * (C) Copyright 2000-2005, by Object Refinery Limited and Contributors.
    006 *
    007 * Project Info:  http://www.jfree.org/jcommon/index.html
    008 *
    009 * This library is free software; you can redistribute it and/or modify it
    010 * under the terms of the GNU Lesser General Public License as published by
    011 * the Free Software Foundation; either version 2.1 of the License, or
    012 * (at your option) any later version.
    013 *
    014 * This library is distributed in the hope that it will be useful, but
    015 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
    016 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
    017 * License for more details.
    018 *
    019 * You should have received a copy of the GNU Lesser General Public
    020 * License along with this library; if not, write to the Free Software
    021 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
    022 * USA.
    023 *
    024 * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
    025 * in the United States and other countries.]
    026 *
    027 * -------------------
    028 * ArrayUtilities.java
    029 * -------------------
    030 * (C) Copyright 2003-2005, by Object Refinery Limited.
    031 *
    032 * Original Author:  David Gilbert (for Object Refinery Limited);
    033 * Contributor(s):   -;
    034 *
    035 * $Id: ArrayUtilities.java,v 1.7 2008/09/10 09:21:30 mungady Exp $
    036 *
    037 * Changes
    038 * -------
    039 * 21-Aug-2003 : Version 1 (DG);
    040 * 04-Oct-2004 : Renamed ArrayUtils --> ArrayUtilities (DG);
    041 *
    042 */
    043
    044package org.jfree.util;
    045
    046import java.util.Arrays;
    047
    048/**
    049 * Utility methods for working with arrays.
    050 *
    051 * @author David Gilbert
    052 */
    053public class ArrayUtilities {
    054
    055    /**
    056     * Private constructor prevents object creation.
    057     */
    058    private ArrayUtilities() {
    059    }
    060
    061    /**
    062     * Clones a two dimensional array of floats.
    063     *
    064     * @param array  the array.
    065     *
    066     * @return A clone of the array.
    067     */
    068    public static float[][] clone(final float[][] array) {
    069
    070        if (array == null) {
    071            return null;
    072        }
    073        final float[][] result = new float[array.length][];
    074        System.arraycopy(array, 0, result, 0, array.length);
    075
    076        for (int i = 0; i < array.length; i++) {
    077            final float[] child = array[i];
    078            final float[] copychild = new float[child.length];
    079            System.arraycopy(child, 0, copychild, 0, child.length);
    080            result[i] = copychild;
    081        }
    082
    083        return result;
    084
    085    }
    086
    087    /**
    088     * Returns <code>true</code> if all the references in <code>array1</code>
    089     * are equal to all the references in <code>array2</code> (two
    090     * <code>null</code> references are considered equal for this test).
    091     *
    092     * @param array1  the first array (<code>null</code> permitted).
    093     * @param array2  the second array (<code>null</code> permitted).
    094     *
    095     * @return A boolean.
    096     */
    097    public static boolean equalReferencesInArrays(final Object[] array1,
    098                                                  final Object[] array2) {
    099        if (array1 == null) {
    100            return (array2 == null);
    101        }
    102        if (array2 == null) {
    103            return false;
    104        }
    105        if (array1.length != array2.length) {
    106            return false;
    107        }
    108        for (int i = 0; i < array1.length; i++) {
    109            if (array1[i] == null) {
    110                if (array2[i] != null) {
    111                    return false;
    112                }
    113            }
    114            if (array2[i] == null) {
    115                if (array1[i] != null) {
    116                    return false;
    117                }
    118            }
    119            if (array1[i] != array2[i]) {
    120                return false;
    121            }
    122        }
    123        return true;
    124    }
    125
    126    /**
    127     * Tests two float arrays for equality.
    128     *
    129     * @param array1  the first array (<code>null</code> permitted).
    130     * @param array2  the second arrray (<code>null</code> permitted).
    131     *
    132     * @return A boolean.
    133     */
    134    public static boolean equal(final float[][] array1,
    135                                final float[][] array2) {
    136        if (array1 == null) {
    137            return (array2 == null);
    138        }
    139
    140        if (array2 == null) {
    141            return false;
    142        }
    143
    144        if (array1.length != array2.length) {
    145            return false;
    146        }
    147
    148        for (int i = 0; i < array1.length; i++) {
    149            if (!Arrays.equals(array1[i], array2[i])) {
    150                return false;
    151            }
    152        }
    153        return true;
    154    }
    155
    156    /**
    157     * Returns <code>true</code> if any two items in the array are equal to
    158     * one another.  Any <code>null</code> values in the array are ignored.
    159     *
    160     * @param array  the array to check.
    161     *
    162     * @return A boolean.
    163     */
    164    public static boolean hasDuplicateItems(final Object[] array) {
    165        for (int i = 0; i < array.length; i++) {
    166            for (int j = 0; j < i; j++) {
    167                final Object o1 = array[i];
    168                final Object o2 = array[j];
    169                if (o1 != null && o2 != null) {
    170                    if (o1.equals(o2)) {
    171                        return true;
    172                    }
    173                }
    174            }
    175        }
    176        return false;
    177    }
    178
    179    /**
    180     * Compares the initial elements of two arrays.
    181     *
    182     * @param a1  array 1.
    183     * @param a2  array 2.
    184     *
    185     * @return An integer showing the relative ordering.
    186     */
    187    public static int compareVersionArrays (Comparable[] a1, Comparable[] a2)
    188    {
    189      int length = Math.min (a1.length, a2.length);
    190      for (int i = 0; i < length; i++)
    191      {
    192        Comparable o1 = a1[i];
    193        Comparable o2 = a2[i];
    194        if (o1 == null && o2 == null)
    195        {
    196          // cannot decide ..
    197          continue;
    198        }
    199        if (o1 == null)
    200        {
    201          return 1;
    202        }
    203        if (o2 == null)
    204        {
    205           return -1;
    206        }
    207        int retval = o1.compareTo(o2);
    208        if (retval != 0)
    209        {
    210          return retval;
    211        }
    212      }
    213      return 0;
    214    }
    215
    216}