Returns the last index of the given array or -1 if empty or null. - Android java.lang

Android examples for java.lang:Array Element

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Description

Returns the last index of the given array or -1 if empty or null.

Demo Code

/*//from  ww w .  j  a  v a 2  s .c o  m
 * @(#)$Id: ArrayUtils.java 3619 2008-03-26 07:23:03Z yui $
 * 
 * Copyright 2006-2008 Makoto YUI
 * 
 * Licensed 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.
 * 
 * Contributors: Makoto YUI - ported from jakarta commons lang
 */
import java.lang.reflect.Array;
import java.util.Collection;
import java.util.Random;

public class Main{
    /**
     * Returns the last index of the given array or -1 if empty or null. This method can deal with
     * <code>Object</code> arrays and with primitive arrays. This value is one less than the size
     * since arrays indices are 0-based.</p>
     * 
     * <pre>
     * ArrayUtils.lastIndex(null)            = -1
     * ArrayUtils.lastIndex([])              = -1
     * ArrayUtils.lastIndex([null])          = 0
     * ArrayUtils.lastIndex([true, false])   = 1
     * ArrayUtils.lastIndex([1, 2, 3])       = 2
     * ArrayUtils.lastIndex([&quot;a&quot;, &quot;b&quot;, &quot;c&quot;]) = 2
     * </pre>
     * 
     * @param array
     *          the array to return the last index for, may be null
     * @return the last index, -1 if empty or null
     * @throws IllegalArgumentException
     *           if the object arguement is not an array.
     */
    public static int lastIndex(final Object array) {
        return ArrayUtils.getLength(array) - 1;
    }
    /**
     * <p>
     * Returns the length of the specified array. This method can deal with <code>Object</code> arrays
     * and with primitive arrays.
     * </p>
     * 
     * <p>
     * If the input array is <code>null</code>, <code>0</code> is returned.
     * </p>
     * 
     * <pre>
     * ArrayUtils.getLength(null)            = 0
     * ArrayUtils.getLength([])              = 0
     * ArrayUtils.getLength([null])          = 1
     * ArrayUtils.getLength([true, false])   = 2
     * ArrayUtils.getLength([1, 2, 3])       = 3
     * ArrayUtils.getLength([&quot;a&quot;, &quot;b&quot;, &quot;c&quot;]) = 3
     * </pre>
     * 
     * @param array
     *          the array to retrieve the length from, may be null
     * @return The length of the array, or <code>0</code> if the array is <code>null</code>
     * @throws IllegalArgumentException
     *           if the object arguement is not an array.
     */
    public static int getLength(final Object array) {
        if (array == null) {
            return 0;
        }
        return Array.getLength(array);
    }
}

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