com.qq.tars.rpc.common.util.concurrent.ConcurrentHashSet Maven / Gradle / Ivy

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/**
 * Tencent is pleased to support the open source community by making Tars available.
 *
 * Copyright (C) 2016 THL A29 Limited, a Tencent company. All rights reserved.
 *
 * Licensed under the BSD 3-Clause License (the "License"); you may not use this file except
 * in compliance with the License. You may obtain a copy of the License at
 *
 * https://opensource.org/licenses/BSD-3-Clause
 *
 * 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.qq.tars.rpc.common.util.concurrent;

import java.util.AbstractSet;
import java.util.Iterator;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;

@SuppressWarnings("serial")
public class ConcurrentHashSet extends AbstractSet implements Set, java.io.Serializable {

    private static final Object OBJECT = new Object();
    private final ConcurrentHashMap map;

    public ConcurrentHashSet() {
        map = new ConcurrentHashMap();
    }

    public ConcurrentHashSet(int initialCapacity) {
        map = new ConcurrentHashMap(initialCapacity);
    }

    public Iterator iterator() {
        return map.keySet().iterator();
    }

    public int size() {
        return map.size();
    }

    public boolean isEmpty() {
        return map.isEmpty();
    }

    public boolean contains(Object o) {
        return map.containsKey(o);
    }

    public boolean add(E e) {
        return map.put(e, OBJECT) == null;
    }

    public boolean remove(Object o) {
        return map.remove(o) == OBJECT;
    }

    public void clear() {
        map.clear();
    }
}