| // CHECKSTYLE_OFF: Copyrighted to Guava Authors. |
| /* |
| * Copyright (C) 2009 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. |
| */ |
| // CHECKSTYLE_ON |
| |
| package java.util.concurrent; |
| |
| import java.util.AbstractMap; |
| import java.util.Collections; |
| import java.util.Enumeration; |
| import java.util.HashMap; |
| import java.util.Map; |
| import java.util.Set; |
| |
| /** |
| * Minimal emulation of {@link java.util.concurrent.ConcurrentHashMap}. |
| * |
| * <p>Note that the javascript is single-threaded, it is essentially a {@link java.util.HashMap}, |
| * implementing the new methods introduced by {@link ConcurrentMap}. |
| * |
| * @param <K> key type |
| * @param <V> value type |
| */ |
| public class ConcurrentHashMap<K, V> extends AbstractMap<K, V> implements ConcurrentMap<K, V> { |
| |
| private final Map<K, V> backingMap; |
| |
| public ConcurrentHashMap() { |
| this.backingMap = new HashMap<K, V>(); |
| } |
| |
| public ConcurrentHashMap(int initialCapacity) { |
| this.backingMap = new HashMap<K, V>(initialCapacity); |
| } |
| |
| public ConcurrentHashMap(int initialCapacity, float loadFactor) { |
| this.backingMap = new HashMap<K, V>(initialCapacity, loadFactor); |
| } |
| |
| public ConcurrentHashMap(Map<? extends K, ? extends V> t) { |
| this.backingMap = new HashMap<K, V>(t); |
| } |
| |
| public V putIfAbsent(K key, V value) { |
| if (!containsKey(key)) { |
| return put(key, value); |
| } else { |
| return get(key); |
| } |
| } |
| |
| public boolean remove(Object key, Object value) { |
| if (containsKey(key) && get(key).equals(value)) { |
| remove(key); |
| return true; |
| } else { |
| return false; |
| } |
| } |
| |
| public boolean replace(K key, V oldValue, V newValue) { |
| if (oldValue == null || newValue == null) { |
| throw new NullPointerException(); |
| } else if (containsKey(key) && get(key).equals(oldValue)) { |
| put(key, newValue); |
| return true; |
| } else { |
| return false; |
| } |
| } |
| |
| public V replace(K key, V value) { |
| if (value == null) { |
| throw new NullPointerException(); |
| } else if (containsKey(key)) { |
| return put(key, value); |
| } else { |
| return null; |
| } |
| } |
| |
| @Override public boolean containsKey(Object key) { |
| if (key == null) { |
| throw new NullPointerException(); |
| } |
| return backingMap.containsKey(key); |
| } |
| |
| @Override public V get(Object key) { |
| if (key == null) { |
| throw new NullPointerException(); |
| } |
| return backingMap.get(key); |
| } |
| |
| @Override public V put(K key, V value) { |
| if (key == null || value == null) { |
| throw new NullPointerException(); |
| } |
| return backingMap.put(key, value); |
| } |
| |
| @Override public boolean containsValue(Object value) { |
| if (value == null) { |
| throw new NullPointerException(); |
| } |
| return backingMap.containsValue(value); |
| } |
| |
| @Override public V remove(Object key) { |
| if (key == null) { |
| throw new NullPointerException(); |
| } |
| return backingMap.remove(key); |
| } |
| |
| @Override public Set<Entry<K, V>> entrySet() { |
| return backingMap.entrySet(); |
| } |
| |
| public boolean contains(Object value) { |
| return containsValue(value); |
| } |
| |
| public Enumeration<V> elements() { |
| return Collections.enumeration(values()); |
| } |
| |
| public Enumeration<K> keys() { |
| return Collections.enumeration(keySet()); |
| } |
| } |