| /* |
| * Copyright (C) 2007 The Guava Authors |
| * |
| * 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. |
| */ |
| |
| package com.google.common.base; |
| |
| import com.google.common.annotations.GwtCompatible; |
| import java.util.Arrays; |
| import org.checkerframework.checker.nullness.qual.Nullable; |
| |
| /** |
| * Helper functions that can operate on any {@code Object}. |
| * |
| * <p>See the Guava User Guide on <a |
| * href="https://github.com/google/guava/wiki/CommonObjectUtilitiesExplained">writing {@code Object} |
| * methods with {@code Objects}</a>. |
| * |
| * @author Laurence Gonsalves |
| * @since 2.0 |
| */ |
| @GwtCompatible |
| public final class Objects extends ExtraObjectsMethodsForWeb { |
| private Objects() {} |
| |
| /** |
| * Determines whether two possibly-null objects are equal. Returns: |
| * |
| * <ul> |
| * <li>{@code true} if {@code a} and {@code b} are both null. |
| * <li>{@code true} if {@code a} and {@code b} are both non-null and they are equal according to |
| * {@link Object#equals(Object)}. |
| * <li>{@code false} in all other situations. |
| * </ul> |
| * |
| * <p>This assumes that any non-null objects passed to this function conform to the {@code |
| * equals()} contract. |
| * |
| * <p><b>Note for Java 7 and later:</b> This method should be treated as deprecated; use {@link |
| * java.util.Objects#equals} instead. |
| */ |
| public static boolean equal(@Nullable Object a, @Nullable Object b) { |
| return a == b || (a != null && a.equals(b)); |
| } |
| |
| /** |
| * Generates a hash code for multiple values. The hash code is generated by calling {@link |
| * Arrays#hashCode(Object[])}. Note that array arguments to this method, with the exception of a |
| * single Object array, do not get any special handling; their hash codes are based on identity |
| * and not contents. |
| * |
| * <p>This is useful for implementing {@link Object#hashCode()}. For example, in an object that |
| * has three properties, {@code x}, {@code y}, and {@code z}, one could write: |
| * |
| * <pre>{@code |
| * public int hashCode() { |
| * return Objects.hashCode(getX(), getY(), getZ()); |
| * } |
| * }</pre> |
| * |
| * <p><b>Warning:</b> When a single object is supplied, the returned hash code does not equal the |
| * hash code of that object. |
| * |
| * <p><b>Note for Java 7 and later:</b> This method should be treated as deprecated; use {@link |
| * java.util.Objects#hash} instead. |
| */ |
| public static int hashCode(@Nullable Object @Nullable ... objects) { |
| return Arrays.hashCode(objects); |
| } |
| } |