android/support/v4/util/ObjectsCompat.java


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/*
 * 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));
        }
    }
}