ArrayUtils工具类

package cn.trinea.android.common.util;/** * Array Utils * <ul> * <li>{@link #isEmpty(Object[])} is null or its length is 0</li> * <li>{@link #getLast(Object[], Object, Object, boolean)} get last element of the target element, before the first one * that match the target element front to back</li> * <li>{@link #getNext(Object[], Object, Object, boolean)} get next element of the target element, after the first one * that match the target element front to back</li> * <li>{@link #getLast(Object[], Object, boolean)}</li> * <li>{@link #getLast(int[], int, int, boolean)}</li> * <li>{@link #getLast(long[], long, long, boolean)}</li> * <li>{@link #getNext(Object[], Object, boolean)}</li> * <li>{@link #getNext(int[], int, int, boolean)}</li> * <li>{@link #getNext(long[], long, long, boolean)}</li> * </ul> *  * @author <a href="http://www.trinea.cn" target="_blank">Trinea</a> 2011-10-24 */public class ArrayUtils {    private ArrayUtils() {        throw new AssertionError();    }    /**     * is null or its length is 0     *      * @param <V>     * @param sourceArray     * @return     */    public static <V> boolean isEmpty(V[] sourceArray) {        return (sourceArray == null || sourceArray.length == 0);    }    /**     * get last element of the target element, before the first one that match the target element front to back     * <ul>     * <li>if array is empty, return defaultValue</li>     * <li>if target element is not exist in array, return defaultValue</li>     * <li>if target element exist in array and its index is not 0, return the last element</li>     * <li>if target element exist in array and its index is 0, return the last one in array if isCircle is true, else     * return defaultValue</li>     * </ul>     *      * @param <V>     * @param sourceArray     * @param value value of target element     * @param defaultValue default return value     * @param isCircle whether is circle     * @return     */    public static <V> V getLast(V[] sourceArray, V value, V defaultValue, boolean isCircle) {        if (isEmpty(sourceArray)) {            return defaultValue;        }        int currentPosition = -1;        for (int i = 0; i < sourceArray.length; i++) {            if (ObjectUtils.isEquals(value, sourceArray[i])) {                currentPosition = i;                break;            }        }        if (currentPosition == -1) {            return defaultValue;        }        if (currentPosition == 0) {            return isCircle ? sourceArray[sourceArray.length - 1] : defaultValue;        }        return sourceArray[currentPosition - 1];    }    /**     * get next element of the target element, after the first one that match the target element front to back     * <ul>     * <li>if array is empty, return defaultValue</li>     * <li>if target element is not exist in array, return defaultValue</li>     * <li>if target element exist in array and not the last one in array, return the next element</li>     * <li>if target element exist in array and the last one in array, return the first one in array if isCircle is     * true, else return defaultValue</li>     * </ul>     *      * @param <V>     * @param sourceArray     * @param value value of target element     * @param defaultValue default return value     * @param isCircle whether is circle     * @return     */    public static <V> V getNext(V[] sourceArray, V value, V defaultValue, boolean isCircle) {        if (isEmpty(sourceArray)) {            return defaultValue;        }        int currentPosition = -1;        for (int i = 0; i < sourceArray.length; i++) {            if (ObjectUtils.isEquals(value, sourceArray[i])) {                currentPosition = i;                break;            }        }        if (currentPosition == -1) {            return defaultValue;        }        if (currentPosition == sourceArray.length - 1) {            return isCircle ? sourceArray[0] : defaultValue;        }        return sourceArray[currentPosition + 1];    }    /**     * @see {@link ArrayUtils#getLast(Object[], Object, Object, boolean)} defaultValue is null     */    public static <V> V getLast(V[] sourceArray, V value, boolean isCircle) {        return getLast(sourceArray, value, null, isCircle);    }    /**     * @see {@link ArrayUtils#getNext(Object[], Object, Object, boolean)} defaultValue is null     */    public static <V> V getNext(V[] sourceArray, V value, boolean isCircle) {        return getNext(sourceArray, value, null, isCircle);    }    /**     * @see {@link ArrayUtils#getLast(Object[], Object, Object, boolean)} Object is Long     */    public static long getLast(long[] sourceArray, long value, long defaultValue, boolean isCircle) {        if (sourceArray.length == 0) {            throw new IllegalArgumentException("The length of source array must be greater than 0.");        }        Long[] array = ObjectUtils.transformLongArray(sourceArray);        return getLast(array, value, defaultValue, isCircle);    }    /**     * @see {@link ArrayUtils#getNext(Object[], Object, Object, boolean)} Object is Long     */    public static long getNext(long[] sourceArray, long value, long defaultValue, boolean isCircle) {        if (sourceArray.length == 0) {            throw new IllegalArgumentException("The length of source array must be greater than 0.");        }        Long[] array = ObjectUtils.transformLongArray(sourceArray);        return getNext(array, value, defaultValue, isCircle);    }    /**     * @see {@link ArrayUtils#getLast(Object[], Object, Object, boolean)} Object is Integer     */    public static int getLast(int[] sourceArray, int value, int defaultValue, boolean isCircle) {        if (sourceArray.length == 0) {            throw new IllegalArgumentException("The length of source array must be greater than 0.");        }        Integer[] array = ObjectUtils.transformIntArray(sourceArray);        return getLast(array, value, defaultValue, isCircle);    }    /**     * @see {@link ArrayUtils#getNext(Object[], Object, Object, boolean)} Object is Integer     */    public static int getNext(int[] sourceArray, int value, int defaultValue, boolean isCircle) {        if (sourceArray.length == 0) {            throw new IllegalArgumentException("The length of source array must be greater than 0.");        }        Integer[] array = ObjectUtils.transformIntArray(sourceArray);        return getNext(array, value, defaultValue, isCircle);    }}