diff --git a/jdk/make/java/java/FILES_java.gmk b/jdk/make/java/java/FILES_java.gmk index 2ad599cbe235749e97c5128835fc249191bce42c..d9b7e153d727147a3d9f48991d103b4f29f582a6 100644 --- a/jdk/make/java/java/FILES_java.gmk +++ b/jdk/make/java/java/FILES_java.gmk @@ -258,6 +258,7 @@ JAVA_JAVA_java = \ java/util/ServiceConfigurationError.java \ java/util/Timer.java \ java/util/TimerTask.java \ + java/util/Objects.java \ java/util/UUID.java \ java/util/concurrent/AbstractExecutorService.java \ java/util/concurrent/ArrayBlockingQueue.java \ diff --git a/jdk/src/share/classes/java/util/Objects.java b/jdk/src/share/classes/java/util/Objects.java new file mode 100644 index 0000000000000000000000000000000000000000..9d05c314d891d82a076b2ee612c3bbb516e4ed8c --- /dev/null +++ b/jdk/src/share/classes/java/util/Objects.java @@ -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. + * + *

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 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 int compare(T a, T b, Comparator c) { + return (a == b) ? 0 : c.compare(a, b); + } +} diff --git a/jdk/test/java/util/Objects/BasicObjectsTest.java b/jdk/test/java/util/Objects/BasicObjectsTest.java new file mode 100644 index 0000000000000000000000000000000000000000..be45b2c92edbc47fe784b4752f735d2d057fef35 --- /dev/null +++ b/jdk/test/java/util/Objects/BasicObjectsTest.java @@ -0,0 +1,105 @@ +/* + * 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. + * + * 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. + */ + +/* + * @test + * @bug 6797535 + * @summary Basic tests for methods in java.util.Objects + * @author Joseph D. Darcy + */ + +import java.util.*; + +public class BasicObjectsTest { + public static void main(String... args) { + int errors = 0; + errors += testEquals(); + errors += testHashCode(); + errors += testToString(); + errors += testCompare(); + if (errors > 0 ) + throw new RuntimeException(); + } + + private static int testEquals() { + int errors = 0; + Object[] values = {null, "42", 42}; + for(int i = 0; i < values.length; i++) + for(int j = 0; j < values.length; j++) { + boolean expected = (i == j); + Object a = values[i]; + Object b = values[j]; + boolean result = Objects.equals(a, b); + if (result != expected) { + errors++; + System.err.printf("When equating %s to %s, got %b instead of %b%n.", + a, b, result, expected); + } + } + return errors; + } + + private static int testHashCode() { + int errors = 0; + errors += (Objects.hashCode(null) == 0 ) ? 0 : 1; + String s = "42"; + errors += (Objects.hashCode(s) == s.hashCode() ) ? 0 : 1; + return errors; + } + + private static int testToString() { + int errors = 0; + errors += ("null".equals(Objects.toString(null)) ) ? 0 : 1; + String s = "Some string"; + errors += (s.equals(Objects.toString(s)) ) ? 0 : 1; + return errors; + } + + private static int testCompare() { + int errors = 0; + String[] values = {"e. e. cummings", "zzz"}; + String[] VALUES = {"E. E. Cummings", "ZZZ"}; + errors += compareTest(null, null, 0); + for(int i = 0; i < values.length; i++) { + String a = values[i]; + errors += compareTest(a, a, 0); + for(int j = 0; j < VALUES.length; j++) { + int expected = Integer.compare(i, j); + String b = VALUES[j]; + errors += compareTest(a, b, expected); + } + } + return errors; + } + + private static int compareTest(String a, String b, int expected) { + int errors = 0; + int result = Objects.compare(a, b, String.CASE_INSENSITIVE_ORDER); + if (Integer.signum(result) != Integer.signum(expected)) { + errors++; + System.err.printf("When comparing %s to %s, got %d instead of %d%n.", + a, b, result, expected); + } + return errors; + } +}