null
+ * or of zero length.
+ * @param array the array to check
+ * @return whether the given array is empty
+ */
+ public static boolean isEmpty(Object[] array) {
+ return (array == null || array.length == 0);
+ }
+
+ /**
+ * Check whether the given array contains the given element.
+ * @param array the array to check (may be null,
+ * in which case the return value will always be false)
+ * @param element the element to check for
+ * @return whether the element has been found in the given array
+ */
+ public static boolean containsElement(Object[] array, Object element) {
+ if (array == null) {
+ return false;
+ }
+ for (int i = 0; i < array.length; i++) {
+ if (nullSafeEquals(array[i], element)) {
+ return true;
+ }
+ }
+ return false;
+ }
+
+ /**
+ * Append the given Object to the given array, returning a new array
+ * consisting of the input array contents plus the given Object.
+ * @param array the array to append to (can be null)
+ * @param obj the Object to append
+ * @return the new array (of the same component type; never null)
+ */
+ public static Object[] addObjectToArray(Object[] array, Object obj) {
+ Class compType = Object.class;
+ if (array != null) {
+ compType = array.getClass().getComponentType();
+ }
+ else if (obj != null) {
+ compType = obj.getClass();
+ }
+ int newArrLength = (array != null ? array.length + 1 : 1);
+ Object[] newArr = (Object[]) Array.newInstance(compType, newArrLength);
+ if (array != null) {
+ System.arraycopy(array, 0, newArr, 0, array.length);
+ }
+ newArr[newArr.length - 1] = obj;
+ return newArr;
+ }
+
+ /**
+ * Convert the given array (which may be a primitive array) to an
+ * object array (if necessary of primitive wrapper objects).
+ * A null source value will be converted to an
+ * empty Object array.
+ * @param source the (potentially primitive) array
+ * @return the corresponding object array (never null)
+ * @throws IllegalArgumentException if the parameter is not an array
+ */
+ public static Object[] toObjectArray(Object source) {
+ if (source instanceof Object[]) {
+ return (Object[]) source;
+ }
+ if (source == null) {
+ return new Object[0];
+ }
+ if (!source.getClass().isArray()) {
+ throw new IllegalArgumentException("Source is not an array: " + source);
+ }
+ int length = Array.getLength(source);
+ if (length == 0) {
+ return new Object[0];
+ }
+ Class wrapperType = Array.get(source, 0).getClass();
+ Object[] newArray = (Object[]) Array.newInstance(wrapperType, length);
+ for (int i = 0; i < length; i++) {
+ newArray[i] = Array.get(source, i);
+ }
+ return newArray;
+ }
+
+
+ //---------------------------------------------------------------------
+ // Convenience methods for content-based equality/hash-code handling
+ //---------------------------------------------------------------------
+
+ /**
+ * Determine if the given objects are equal, returning true
+ * if both are null or false if only one is
+ * null.
+ *
Compares arrays with Arrays.equals, performing an equality
+ * check based on the array elements rather than the array reference.
+ * @param o1 first Object to compare
+ * @param o2 second Object to compare
+ * @return whether the given objects are equal
+ * @see java.util.Arrays#equals
+ */
+ public static boolean nullSafeEquals(Object o1, Object o2) {
+ if (o1 == o2) {
+ return true;
+ }
+ if (o1 == null || o2 == null) {
+ return false;
+ }
+ if (o1.equals(o2)) {
+ return true;
+ }
+ if (o1.getClass().isArray() && o2.getClass().isArray()) {
+ if (o1 instanceof Object[] && o2 instanceof Object[]) {
+ return Arrays.equals((Object[]) o1, (Object[]) o2);
+ }
+ if (o1 instanceof boolean[] && o2 instanceof boolean[]) {
+ return Arrays.equals((boolean[]) o1, (boolean[]) o2);
+ }
+ if (o1 instanceof byte[] && o2 instanceof byte[]) {
+ return Arrays.equals((byte[]) o1, (byte[]) o2);
+ }
+ if (o1 instanceof char[] && o2 instanceof char[]) {
+ return Arrays.equals((char[]) o1, (char[]) o2);
+ }
+ if (o1 instanceof double[] && o2 instanceof double[]) {
+ return Arrays.equals((double[]) o1, (double[]) o2);
+ }
+ if (o1 instanceof float[] && o2 instanceof float[]) {
+ return Arrays.equals((float[]) o1, (float[]) o2);
+ }
+ if (o1 instanceof int[] && o2 instanceof int[]) {
+ return Arrays.equals((int[]) o1, (int[]) o2);
+ }
+ if (o1 instanceof long[] && o2 instanceof long[]) {
+ return Arrays.equals((long[]) o1, (long[]) o2);
+ }
+ if (o1 instanceof short[] && o2 instanceof short[]) {
+ return Arrays.equals((short[]) o1, (short[]) o2);
+ }
+ }
+ return false;
+ }
+
+ /**
+ * Return as hash code for the given object; typically the value of
+ * {@link Object#hashCode()}. If the object is an array,
+ * this method will delegate to any of the nullSafeHashCode
+ * methods for arrays in this class. If the object is null,
+ * this method returns 0.
+ * @see #nullSafeHashCode(Object[])
+ * @see #nullSafeHashCode(boolean[])
+ * @see #nullSafeHashCode(byte[])
+ * @see #nullSafeHashCode(char[])
+ * @see #nullSafeHashCode(double[])
+ * @see #nullSafeHashCode(float[])
+ * @see #nullSafeHashCode(int[])
+ * @see #nullSafeHashCode(long[])
+ * @see #nullSafeHashCode(short[])
+ */
+ public static int nullSafeHashCode(Object obj) {
+ if (obj == null) {
+ return 0;
+ }
+ if (obj.getClass().isArray()) {
+ if (obj instanceof Object[]) {
+ return nullSafeHashCode((Object[]) obj);
+ }
+ if (obj instanceof boolean[]) {
+ return nullSafeHashCode((boolean[]) obj);
+ }
+ if (obj instanceof byte[]) {
+ return nullSafeHashCode((byte[]) obj);
+ }
+ if (obj instanceof char[]) {
+ return nullSafeHashCode((char[]) obj);
+ }
+ if (obj instanceof double[]) {
+ return nullSafeHashCode((double[]) obj);
+ }
+ if (obj instanceof float[]) {
+ return nullSafeHashCode((float[]) obj);
+ }
+ if (obj instanceof int[]) {
+ return nullSafeHashCode((int[]) obj);
+ }
+ if (obj instanceof long[]) {
+ return nullSafeHashCode((long[]) obj);
+ }
+ if (obj instanceof short[]) {
+ return nullSafeHashCode((short[]) obj);
+ }
+ }
+ return obj.hashCode();
+ }
+
+ /**
+ * Return a hash code based on the contents of the specified array.
+ * If array is null, this method returns 0.
+ */
+ public static int nullSafeHashCode(Object[] array) {
+ if (array == null) {
+ return 0;
+ }
+ int hash = INITIAL_HASH;
+ int arraySize = array.length;
+ for (int i = 0; i < arraySize; i++) {
+ hash = MULTIPLIER * hash + nullSafeHashCode(array[i]);
+ }
+ return hash;
+ }
+
+ /**
+ * Return a hash code based on the contents of the specified array.
+ * If array is null, this method returns 0.
+ */
+ public static int nullSafeHashCode(boolean[] array) {
+ if (array == null) {
+ return 0;
+ }
+ int hash = INITIAL_HASH;
+ int arraySize = array.length;
+ for (int i = 0; i < arraySize; i++) {
+ hash = MULTIPLIER * hash + hashCode(array[i]);
+ }
+ return hash;
+ }
+
+ /**
+ * Return a hash code based on the contents of the specified array.
+ * If array is null, this method returns 0.
+ */
+ public static int nullSafeHashCode(byte[] array) {
+ if (array == null) {
+ return 0;
+ }
+ int hash = INITIAL_HASH;
+ int arraySize = array.length;
+ for (int i = 0; i < arraySize; i++) {
+ hash = MULTIPLIER * hash + array[i];
+ }
+ return hash;
+ }
+
+ /**
+ * Return a hash code based on the contents of the specified array.
+ * If array is null, this method returns 0.
+ */
+ public static int nullSafeHashCode(char[] array) {
+ if (array == null) {
+ return 0;
+ }
+ int hash = INITIAL_HASH;
+ int arraySize = array.length;
+ for (int i = 0; i < arraySize; i++) {
+ hash = MULTIPLIER * hash + array[i];
+ }
+ return hash;
+ }
+
+ /**
+ * Return a hash code based on the contents of the specified array.
+ * If array is null, this method returns 0.
+ */
+ public static int nullSafeHashCode(double[] array) {
+ if (array == null) {
+ return 0;
+ }
+ int hash = INITIAL_HASH;
+ int arraySize = array.length;
+ for (int i = 0; i < arraySize; i++) {
+ hash = MULTIPLIER * hash + hashCode(array[i]);
+ }
+ return hash;
+ }
+
+ /**
+ * Return a hash code based on the contents of the specified array.
+ * If array is null, this method returns 0.
+ */
+ public static int nullSafeHashCode(float[] array) {
+ if (array == null) {
+ return 0;
+ }
+ int hash = INITIAL_HASH;
+ int arraySize = array.length;
+ for (int i = 0; i < arraySize; i++) {
+ hash = MULTIPLIER * hash + hashCode(array[i]);
+ }
+ return hash;
+ }
+
+ /**
+ * Return a hash code based on the contents of the specified array.
+ * If array is null, this method returns 0.
+ */
+ public static int nullSafeHashCode(int[] array) {
+ if (array == null) {
+ return 0;
+ }
+ int hash = INITIAL_HASH;
+ int arraySize = array.length;
+ for (int i = 0; i < arraySize; i++) {
+ hash = MULTIPLIER * hash + array[i];
+ }
+ return hash;
+ }
+
+ /**
+ * Return a hash code based on the contents of the specified array.
+ * If array is null, this method returns 0.
+ */
+ public static int nullSafeHashCode(long[] array) {
+ if (array == null) {
+ return 0;
+ }
+ int hash = INITIAL_HASH;
+ int arraySize = array.length;
+ for (int i = 0; i < arraySize; i++) {
+ hash = MULTIPLIER * hash + hashCode(array[i]);
+ }
+ return hash;
+ }
+
+ /**
+ * Return a hash code based on the contents of the specified array.
+ * If array is null, this method returns 0.
+ */
+ public static int nullSafeHashCode(short[] array) {
+ if (array == null) {
+ return 0;
+ }
+ int hash = INITIAL_HASH;
+ int arraySize = array.length;
+ for (int i = 0; i < arraySize; i++) {
+ hash = MULTIPLIER * hash + array[i];
+ }
+ return hash;
+ }
+
+ /**
+ * Return the same value as {@link Boolean#hashCode()}.
+ * @see Boolean#hashCode()
+ */
+ public static int hashCode(boolean bool) {
+ return bool ? 1231 : 1237;
+ }
+
+ /**
+ * Return the same value as {@link Double#hashCode()}.
+ * @see Double#hashCode()
+ */
+ public static int hashCode(double dbl) {
+ long bits = Double.doubleToLongBits(dbl);
+ return hashCode(bits);
+ }
+
+ /**
+ * Return the same value as {@link Float#hashCode()}.
+ * @see Float#hashCode()
+ */
+ public static int hashCode(float flt) {
+ return Float.floatToIntBits(flt);
+ }
+
+ /**
+ * Return the same value as {@link Long#hashCode()}.
+ * @see Long#hashCode()
+ */
+ public static int hashCode(long lng) {
+ return (int) (lng ^ (lng >>> 32));
+ }
+
+
+ //---------------------------------------------------------------------
+ // Convenience methods for toString output
+ //---------------------------------------------------------------------
+
+ /**
+ * Return a String representation of an object's overall identity.
+ * @param obj the object (may be null)
+ * @return the object's identity as String representation,
+ * or an empty String if the object was null
+ */
+ public static String identityToString(Object obj) {
+ if (obj == null) {
+ return EMPTY_STRING;
+ }
+ return obj.getClass().getName() + "@" + getIdentityHexString(obj);
+ }
+
+ /**
+ * Return a hex String form of an object's identity hash code.
+ * @param obj the object
+ * @return the object's identity code in hex notation
+ */
+ public static String getIdentityHexString(Object obj) {
+ return Integer.toHexString(System.identityHashCode(obj));
+ }
+
+ /**
+ * Return a content-based String representation if obj is
+ * not null; otherwise returns an empty String.
+ *
Differs from {@link #nullSafeToString(Object)} in that it returns
+ * an empty String rather than "null" for a null value.
+ * @param obj the object to build a display String for
+ * @return a display String representation of obj
+ * @see #nullSafeToString(Object)
+ */
+ public static String getDisplayString(Object obj) {
+ if (obj == null) {
+ return EMPTY_STRING;
+ }
+ return nullSafeToString(obj);
+ }
+
+ /**
+ * Determine the class name for the given object.
+ *
Returns "null" if obj is null.
+ * @param obj the object to introspect (may be null)
+ * @return the corresponding class name
+ */
+ public static String nullSafeClassName(Object obj) {
+ return (obj != null ? obj.getClass().getName() : NULL_STRING);
+ }
+
+ /**
+ * Return a String representation of the specified Object.
+ *
Builds a String representation of the contents in case of an array.
+ * Returns "null" if obj is null.
+ * @param obj the object to build a String representation for
+ * @return a String representation of obj
+ */
+ public static String nullSafeToString(Object obj) {
+ if (obj == null) {
+ return NULL_STRING;
+ }
+ if (obj instanceof String) {
+ return (String) obj;
+ }
+ if (obj instanceof Object[]) {
+ return nullSafeToString((Object[]) obj);
+ }
+ if (obj instanceof boolean[]) {
+ return nullSafeToString((boolean[]) obj);
+ }
+ if (obj instanceof byte[]) {
+ return nullSafeToString((byte[]) obj);
+ }
+ if (obj instanceof char[]) {
+ return nullSafeToString((char[]) obj);
+ }
+ if (obj instanceof double[]) {
+ return nullSafeToString((double[]) obj);
+ }
+ if (obj instanceof float[]) {
+ return nullSafeToString((float[]) obj);
+ }
+ if (obj instanceof int[]) {
+ return nullSafeToString((int[]) obj);
+ }
+ if (obj instanceof long[]) {
+ return nullSafeToString((long[]) obj);
+ }
+ if (obj instanceof short[]) {
+ return nullSafeToString((short[]) obj);
+ }
+ String str = obj.toString();
+ return (str != null ? str : EMPTY_STRING);
+ }
+
+ /**
+ * Return a String representation of the contents of the specified array.
+ *
The String representation consists of a list of the array's elements,
+ * enclosed in curly braces ("{}"). Adjacent elements are separated
+ * by the characters ", " (a comma followed by a space). Returns
+ * "null" if array is null.
+ * @param array the array to build a String representation for
+ * @return a String representation of array
+ */
+ public static String nullSafeToString(Object[] array) {
+ if (array == null) {
+ return NULL_STRING;
+ }
+ int length = array.length;
+ if (length == 0) {
+ return EMPTY_ARRAY;
+ }
+ StringBuffer buffer = new StringBuffer();
+ for (int i = 0; i < length; i++) {
+ if (i == 0) {
+ buffer.append(ARRAY_START);
+ }
+ else {
+ buffer.append(ARRAY_ELEMENT_SEPARATOR);
+ }
+ buffer.append(String.valueOf(array[i]));
+ }
+ buffer.append(ARRAY_END);
+ return buffer.toString();
+ }
+
+ /**
+ * Return a String representation of the contents of the specified array.
+ *
The String representation consists of a list of the array's elements,
+ * enclosed in curly braces ("{}"). Adjacent elements are separated
+ * by the characters ", " (a comma followed by a space). Returns
+ * "null" if array is null.
+ * @param array the array to build a String representation for
+ * @return a String representation of array
+ */
+ public static String nullSafeToString(boolean[] array) {
+ if (array == null) {
+ return NULL_STRING;
+ }
+ int length = array.length;
+ if (length == 0) {
+ return EMPTY_ARRAY;
+ }
+ StringBuffer buffer = new StringBuffer();
+ for (int i = 0; i < length; i++) {
+ if (i == 0) {
+ buffer.append(ARRAY_START);
+ }
+ else {
+ buffer.append(ARRAY_ELEMENT_SEPARATOR);
+ }
+
+ buffer.append(array[i]);
+ }
+ buffer.append(ARRAY_END);
+ return buffer.toString();
+ }
+
+ /**
+ * Return a String representation of the contents of the specified array.
+ *
The String representation consists of a list of the array's elements,
+ * enclosed in curly braces ("{}"). Adjacent elements are separated
+ * by the characters ", " (a comma followed by a space). Returns
+ * "null" if array is null.
+ * @param array the array to build a String representation for
+ * @return a String representation of array
+ */
+ public static String nullSafeToString(byte[] array) {
+ if (array == null) {
+ return NULL_STRING;
+ }
+ int length = array.length;
+ if (length == 0) {
+ return EMPTY_ARRAY;
+ }
+ StringBuffer buffer = new StringBuffer();
+ for (int i = 0; i < length; i++) {
+ if (i == 0) {
+ buffer.append(ARRAY_START);
+ }
+ else {
+ buffer.append(ARRAY_ELEMENT_SEPARATOR);
+ }
+ buffer.append(array[i]);
+ }
+ buffer.append(ARRAY_END);
+ return buffer.toString();
+ }
+
+ /**
+ * Return a String representation of the contents of the specified array.
+ *
The String representation consists of a list of the array's elements,
+ * enclosed in curly braces ("{}"). Adjacent elements are separated
+ * by the characters ", " (a comma followed by a space). Returns
+ * "null" if array is null.
+ * @param array the array to build a String representation for
+ * @return a String representation of array
+ */
+ public static String nullSafeToString(char[] array) {
+ if (array == null) {
+ return NULL_STRING;
+ }
+ int length = array.length;
+ if (length == 0) {
+ return EMPTY_ARRAY;
+ }
+ StringBuffer buffer = new StringBuffer();
+ for (int i = 0; i < length; i++) {
+ if (i == 0) {
+ buffer.append(ARRAY_START);
+ }
+ else {
+ buffer.append(ARRAY_ELEMENT_SEPARATOR);
+ }
+ buffer.append("'").append(array[i]).append("'");
+ }
+ buffer.append(ARRAY_END);
+ return buffer.toString();
+ }
+
+ /**
+ * Return a String representation of the contents of the specified array.
+ *
The String representation consists of a list of the array's elements,
+ * enclosed in curly braces ("{}"). Adjacent elements are separated
+ * by the characters ", " (a comma followed by a space). Returns
+ * "null" if array is null.
+ * @param array the array to build a String representation for
+ * @return a String representation of array
+ */
+ public static String nullSafeToString(double[] array) {
+ if (array == null) {
+ return NULL_STRING;
+ }
+ int length = array.length;
+ if (length == 0) {
+ return EMPTY_ARRAY;
+ }
+ StringBuffer buffer = new StringBuffer();
+ for (int i = 0; i < length; i++) {
+ if (i == 0) {
+ buffer.append(ARRAY_START);
+ }
+ else {
+ buffer.append(ARRAY_ELEMENT_SEPARATOR);
+ }
+
+ buffer.append(array[i]);
+ }
+ buffer.append(ARRAY_END);
+ return buffer.toString();
+ }
+
+ /**
+ * Return a String representation of the contents of the specified array.
+ *
The String representation consists of a list of the array's elements,
+ * enclosed in curly braces ("{}"). Adjacent elements are separated
+ * by the characters ", " (a comma followed by a space). Returns
+ * "null" if array is null.
+ * @param array the array to build a String representation for
+ * @return a String representation of array
+ */
+ public static String nullSafeToString(float[] array) {
+ if (array == null) {
+ return NULL_STRING;
+ }
+ int length = array.length;
+ if (length == 0) {
+ return EMPTY_ARRAY;
+ }
+ StringBuffer buffer = new StringBuffer();
+ for (int i = 0; i < length; i++) {
+ if (i == 0) {
+ buffer.append(ARRAY_START);
+ }
+ else {
+ buffer.append(ARRAY_ELEMENT_SEPARATOR);
+ }
+
+ buffer.append(array[i]);
+ }
+ buffer.append(ARRAY_END);
+ return buffer.toString();
+ }
+
+ /**
+ * Return a String representation of the contents of the specified array.
+ *
The String representation consists of a list of the array's elements,
+ * enclosed in curly braces ("{}"). Adjacent elements are separated
+ * by the characters ", " (a comma followed by a space). Returns
+ * "null" if array is null.
+ * @param array the array to build a String representation for
+ * @return a String representation of array
+ */
+ public static String nullSafeToString(int[] array) {
+ if (array == null) {
+ return NULL_STRING;
+ }
+ int length = array.length;
+ if (length == 0) {
+ return EMPTY_ARRAY;
+ }
+ StringBuffer buffer = new StringBuffer();
+ for (int i = 0; i < length; i++) {
+ if (i == 0) {
+ buffer.append(ARRAY_START);
+ }
+ else {
+ buffer.append(ARRAY_ELEMENT_SEPARATOR);
+ }
+ buffer.append(array[i]);
+ }
+ buffer.append(ARRAY_END);
+ return buffer.toString();
+ }
+
+ /**
+ * Return a String representation of the contents of the specified array.
+ *
The String representation consists of a list of the array's elements,
+ * enclosed in curly braces ("{}"). Adjacent elements are separated
+ * by the characters ", " (a comma followed by a space). Returns
+ * "null" if array is null.
+ * @param array the array to build a String representation for
+ * @return a String representation of array
+ */
+ public static String nullSafeToString(long[] array) {
+ if (array == null) {
+ return NULL_STRING;
+ }
+ int length = array.length;
+ if (length == 0) {
+ return EMPTY_ARRAY;
+ }
+ StringBuffer buffer = new StringBuffer();
+ for (int i = 0; i < length; i++) {
+ if (i == 0) {
+ buffer.append(ARRAY_START);
+ }
+ else {
+ buffer.append(ARRAY_ELEMENT_SEPARATOR);
+ }
+ buffer.append(array[i]);
+ }
+ buffer.append(ARRAY_END);
+ return buffer.toString();
+ }
+
+ /**
+ * Return a String representation of the contents of the specified array.
+ *
The String representation consists of a list of the array's elements,
+ * enclosed in curly braces ("{}"). Adjacent elements are separated
+ * by the characters ", " (a comma followed by a space). Returns
+ * "null" if array is null.
+ * @param array the array to build a String representation for
+ * @return a String representation of array
+ */
+ public static String nullSafeToString(short[] array) {
+ if (array == null) {
+ return NULL_STRING;
+ }
+ int length = array.length;
+ if (length == 0) {
+ return EMPTY_ARRAY;
+ }
+ StringBuffer buffer = new StringBuffer();
+ for (int i = 0; i < length; i++) {
+ if (i == 0) {
+ buffer.append(ARRAY_START);
+ }
+ else {
+ buffer.append(ARRAY_ELEMENT_SEPARATOR);
+ }
+ buffer.append(array[i]);
+ }
+ buffer.append(ARRAY_END);
+ return buffer.toString();
+ }
+
+}