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/*
 *  Licensed to the Apache Software Foundation (ASF) under one
 *  or more contributor license agreements.  See the NOTICE file
 *  distributed with this work for additional information
 *  regarding copyright ownership.  The ASF licenses this file
 *  to you under the Apache License, Version 2.0 (the
 *  "License"); you may not use this file except in compliance
 *  with the License.  You may obtain a copy of the License at
 * 
 *  http://www.apache.org/licenses/LICENSE-2.0
 * 
 *  Unless required by applicable law or agreed to in writing,
 *  software distributed under the License is distributed on an
 *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 *  KIND, either express or implied.  See the License for the
 *  specific language governing permissions and limitations
 *  under the License.
 */
package org.apache.myfaces.shared_impl.util;

import java.lang.reflect.Array;

/**
 * Utility class for managing arrays
 *
 * @author Anton Koinov (latest modification by $Author: matzew $)
 * @version $Revision: 557350 $ $Date: 2007-07-18 13:19:50 -0500 (Wed, 18 Jul 2007) $
 */
public class ArrayUtils
{
    public static final Object[] EMPTY_OBJECT_ARRAY = new Object[0];
    public static final String[] EMPTY_STRING_ARRAY = new String[0];

    //~ Constructors -------------------------------------------------------------------------------

    protected ArrayUtils()
    {
        // hide from public access
    }

    //~ Methods ------------------------------------------------------------------------------------

    public static Class commonClass(Class c1, Class c2)
    {
        if (c1 == c2)
        {
            return c1;
        }

        if ((c1 == Object.class) || c1.isAssignableFrom(c2))
        {
            return c1;
        }

        if (c2.isAssignableFrom(c1))
        {
            return c2;
        }

        if (c1.isPrimitive() || c2.isPrimitive())
        {
            // REVISIT: we could try to autoconvert to Object or something appropriate
            throw new IllegalArgumentException("incompatible types " + c1 + " and " + c2);
        }

        // REVISIT: we could try to find a common supper class or interface
        return Object.class;
    }

    /**
     * Concatenates two arrays into one. If arr1 is null or empty, returns arr2.
     * If arr2 is null or empty, returns arr1. May return null if both arrays are null,
     * or one is empty and the other null. 
* The concatenated array has componentType which is compatible with both input arrays (or Object[]) * * @param arr1 input array * @param arr2 input array * * @return Object the concatenated array, elements of arr1 first */ public static Object concat(Object arr1, Object arr2) { int len1 = (arr1 == null) ? (-1) : Array.getLength(arr1); if (len1 <= 0) { return arr2; } int len2 = (arr2 == null) ? (-1) : Array.getLength(arr2); if (len2 <= 0) { return arr1; } Class commonComponentType = commonClass(arr1.getClass().getComponentType(), arr2.getClass().getComponentType()); Object newArray = Array.newInstance(commonComponentType, len1 + len2); System.arraycopy(arr1, 0, newArray, 0, len1); System.arraycopy(arr2, 0, newArray, len1, len2); return newArray; } /** * Concatenates arrays into one. Any null or empty arrays are ignored. * If all arrays are null or empty, returns null. * Elements will be ordered in the order in which the arrays are supplied. * * @param arrs array of arrays * @return the concatenated array */ public static Object concat(Object[] arrs) { int totalLen = 0; Class commonComponentType = null; for (int i = 0, len = arrs.length; i < len; i++) { // skip all null arrays if (arrs[i] == null) { continue; } int arrayLen = Array.getLength(arrs[i]); // skip all empty arrays if (arrayLen == 0) { continue; } totalLen += arrayLen; Class componentType = arrs[i].getClass().getComponentType(); commonComponentType = (commonComponentType == null) ? componentType : commonClass(commonComponentType, componentType); } if (commonComponentType == null) { return null; } return concat(Array.newInstance(commonComponentType, totalLen), totalLen, arrs); } public static Object concat(Object toArray, int totalLen, Object[] arrs) { if (totalLen == 0) { // Should we allocate an empty array instead? return toArray; } if (totalLen > Array.getLength(toArray)) { toArray = Array.newInstance(toArray.getClass().getComponentType(), totalLen); } for (int i = 0, len = arrs.length, offset = 0; i < len; i++) { final Object arr = arrs[i]; if (arr != null) { int arrayLen = Array.getLength(arr); if (arrayLen > 0) { System.arraycopy(arr, 0, toArray, offset, arrayLen); offset += arrayLen; } } } return toArray; } public static Object concat(Object arr1, Object arr2, Object arr3) { return concat(new Object[] {arr1, arr2, arr3}); } public static Object concat(Object arr1, Object arr2, Object arr3, Object arr4) { return concat(new Object[] {arr1, arr2, arr3, arr4}); } public static Object concat(Object arr1, Object arr2, Object arr3, Object arr4, Object arr5) { return concat(new Object[] {arr1, arr2, arr3, arr4, arr5}); } public static Object concatSameType(Object toArray, Object[] arrs) { int totalLen = 0; for (int i = 0, len = arrs.length; i < len; i++) { if (arrs[i] != null) { totalLen += Array.getLength(arrs[i]); } } return concat(toArray, totalLen, arrs); } public static boolean contains(Object[] array, Object value) { if (array == null || array.length == 0) { return false; } for (int i = 0; i < array.length; i++) { Object o = array[i]; if ((o == null && value == null) || (o != null && o.equals(value))) { return true; } } return false; } // public static void main(String[] args) // { // // test code // System.out.println(concat(new String[] {"a"}, new Object[] {"b"})); // System.out.println(concat(new String[] {"a"}, new Integer[] {new Integer(0)})); // System.out.println(concat(new Number[] {new Double(0)}, new Integer[] {new Integer(0)})); // System.out.println(concat(new Number[] {}, new Integer[0])); // System.out.println(concat(new Integer[] {new Integer(0)}, new Number[0])); // System.out.println(concat(new Integer[] {new Integer(0)}, new Number[0], new int[0])); // System.out.println( // concat(new Integer[] {new Integer(0)}, new Number[] {new Double(0)}, new int[0])); // System.out.println(concat(new int[] {1}, new int[] {2})); // System.out.println( // concat(new String[] {"a"}, new Integer[] {new Integer(0)}, new Object[] {"b"})); // System.out.println( // concat(new String[0], new Object[] {new String[] {"a"}, new Object[] {"b"}})); // System.out.println( // concat(new Integer[] {new Integer(0)}, new Number[] {new Double(0)}, new int[] {1})); // } }




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