001/* 002 * Copyright (C) 2010 The Guava Authors 003 * 004 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except 005 * in compliance with the License. You may obtain a copy of the License at 006 * 007 * http://www.apache.org/licenses/LICENSE-2.0 008 * 009 * Unless required by applicable law or agreed to in writing, software distributed under the License 010 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express 011 * or implied. See the License for the specific language governing permissions and limitations under 012 * the License. 013 */ 014 015package com.google.common.util.concurrent; 016 017import com.google.common.annotations.GwtIncompatible; 018import java.util.concurrent.atomic.AtomicReference; 019import java.util.concurrent.atomic.AtomicReferenceArray; 020import org.checkerframework.checker.nullness.qual.Nullable; 021 022/** 023 * Static utility methods pertaining to classes in the {@code java.util.concurrent.atomic} package. 024 * 025 * @author Kurt Alfred Kluever 026 * @since 10.0 027 */ 028@GwtIncompatible 029@ElementTypesAreNonnullByDefault 030public final class Atomics { 031 private Atomics() {} 032 033 /** 034 * Creates an {@code AtomicReference} instance with no initial value. 035 * 036 * @return a new {@code AtomicReference} with no initial value 037 */ 038 public static <V> AtomicReference<@Nullable V> newReference() { 039 return new AtomicReference<>(); 040 } 041 042 /** 043 * Creates an {@code AtomicReference} instance with the given initial value. 044 * 045 * @param initialValue the initial value 046 * @return a new {@code AtomicReference} with the given initial value 047 */ 048 public static <V extends @Nullable Object> AtomicReference<V> newReference( 049 @ParametricNullness V initialValue) { 050 return new AtomicReference<>(initialValue); 051 } 052 053 /** 054 * Creates an {@code AtomicReferenceArray} instance of given length. 055 * 056 * @param length the length of the array 057 * @return a new {@code AtomicReferenceArray} with the given length 058 */ 059 public static <E> AtomicReferenceArray<@Nullable E> newReferenceArray(int length) { 060 return new AtomicReferenceArray<>(length); 061 } 062 063 /** 064 * Creates an {@code AtomicReferenceArray} instance with the same length as, and all elements 065 * copied from, the given array. 066 * 067 * @param array the array to copy elements from 068 * @return a new {@code AtomicReferenceArray} copied from the given array 069 */ 070 public static <E extends @Nullable Object> AtomicReferenceArray<E> newReferenceArray(E[] array) { 071 return new AtomicReferenceArray<>(array); 072 } 073}