com.google.common.base.Objects Maven / Gradle / Ivy
/*
* 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 javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;
/**
* Helper functions that can operate on any {@code Object}.
*
* See the Guava User Guide on writing {@code Object}
* methods with {@code Objects}.
*
* @author Laurence Gonsalves
* @since 2.0
*/
@GwtCompatible
@ElementTypesAreNonnullByDefault
public final class Objects extends ExtraObjectsMethodsForWeb {
private Objects() {}
/**
* Determines whether two possibly-null objects are equal. Returns:
*
*
* - {@code true} if {@code a} and {@code b} are both null.
*
- {@code true} if {@code a} and {@code b} are both non-null and they are equal according to
* {@link Object#equals(Object)}.
*
- {@code false} in all other situations.
*
*
* This assumes that any non-null objects passed to this function conform to the {@code
* equals()} contract.
*
*
Note for Java 7 and later: This method should be treated as deprecated; use {@link
* java.util.Objects#equals} instead.
*/
public static boolean equal(@CheckForNull Object a, @CheckForNull 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.
*
*
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:
*
*
{@code
* public int hashCode() {
* return Objects.hashCode(getX(), getY(), getZ());
* }
* }
*
* Warning: When a single object is supplied, the returned hash code does not equal the
* hash code of that object.
*
*
Note for Java 7 and later: This method should be treated as deprecated; use {@link
* java.util.Objects#hash} instead.
*/
public static int hashCode(@CheckForNull @Nullable Object... objects) {
return Arrays.hashCode(objects);
}
}