--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/share/classes/java/util/Objects.java Fri Oct 09 16:11:11 2009 -0700
@@ -0,0 +1,110 @@
+/*
+ * Copyright 2009 Sun Microsystems, Inc. All Rights Reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation. Sun designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Sun in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+
+package java.util;
+
+/**
+ * This class consists of {@code static} utility methods for operating
+ * on objects. These utilities include {@code null}-safe or {@code
+ * null}-tolerant methods for computing the hash code of an object,
+ * returning a string for an object, and comparing two objects.
+ *
+ * @since 1.7
+ */
+public class Objects {
+ private Objects() {
+ throw new AssertionError("No java.util.Objects instances for you!");
+ }
+
+ /**
+ * Returns {@code true} if the arguments are equal to each other
+ * and {@code false} otherwise.
+ * Consequently, if both arguments are {@code null}, {@code true}
+ * is returned and if exactly one argument is {@code null}, {@code
+ * false} is returned. Otherwise, equality is determined by using
+ * the {@link Object#equals equals} method of the first
+ * argument.
+ *
+ * @param a an object
+ * @param b an object to be compared with {@code a} for equality
+ * @return {@code true} if the arguments are equal to each other
+ * and {@code false} otherwise
+ * @see Object#equals(Object)
+ */
+ public static boolean equals(Object a, Object b) {
+ return (a == b) || (a != null && a.equals(b));
+ }
+
+ /**
+ * Returns the hash code of a non-{@code null} argument and 0 for
+ * a {@code null} argument.
+ *
+ * @param o an object
+ * @return the hash code of a non-{@code null} argument and 0 for
+ * a {@code null} argument
+ * @see Object#hashCode
+ */
+ public static int hashCode(Object o) {
+ return o != null ? o.hashCode() : 0;
+ }
+
+ /**
+ * Returns the result of calling {@code toString} for a non-{@code
+ * null} argument and {@code "null"} for a {@code null} argument.
+ *
+ * @param o an object
+ * @return the result of calling {@code toString} for a non-{@code
+ * null} argument and {@code "null"} for a {@code null} argument
+ * @see Object#toString
+ * @see String#valueOf(Object)
+ */
+ public static String toString(Object o) {
+ return String.valueOf(o);
+ }
+
+ /**
+ * Returns 0 if the arguments are identical and {@code
+ * c.compare(a, b)} otherwise.
+ * Consequently, if both arguments are {@code null} 0
+ * is returned.
+ *
+ * <p>Note that if one of the arguments is {@code null}, a {@code
+ * NullPointerException} may or may not be thrown depending on
+ * what ordering policy, if any, the {@link Comparator Comparator}
+ * chooses to have for {@code null} values.
+ *
+ * @param <T> the type of the objects being compared
+ * @param a an object
+ * @param b an object to be compared with {@code a}
+ * @param c the {@code Comparator} to compare the first two arguments
+ * @return 0 if the arguments are identical and {@code
+ * c.compare(a, b)} otherwise.
+ * @see Comparable
+ * @see Comparator
+ */
+ public static <T> int compare(T a, T b, Comparator<? super T> c) {
+ return (a == b) ? 0 : c.compare(a, b);
+ }
+}