Java tutorial
/* * Copyright (C) 2017 The Android Open Source Project * * 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 android.support.v4.util; import android.os.Build; import android.support.annotation.Nullable; import java.util.Objects; /** * This class consists of static utility methods for operating on objects. */ public class ObjectsCompat { private ObjectsCompat() { // Non-instantiable. } /** * Returns {@code true} if the arguments are equal to each other * and {@code false} otherwise. * <p> * 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(@Nullable Object a, @Nullable Object b) { if (Build.VERSION.SDK_INT >= 19) { return Objects.equals(a, b); } else { return (a == b) || (a != null && a.equals(b)); } } }