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/*
 * (C) 2007-2012 Alibaba Group Holding Limited.
 * 
 * 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.
 */

/*
 *  Licensed to the Apache Software Foundation (ASF) under one
 *  or more contributor license agreements.  See the NOTICE file
 *  distributed with this work for additional information
 *  regarding copyright ownership.  The ASF licenses this file
 *  to you 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.taobao.metamorphosis.server.utils;

import java.io.Serializable;
import java.util.Collection;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;


/**
 * ??????mina??ĿApache MINA Project
 * 
 * @modification by ?޻?
 * @since 2011-8-11 ????3:08:09
 */

public class CopyOnWriteMap implements Map, Cloneable, Serializable {
    private static final long serialVersionUID = 788933834504546710L;

    private volatile Map internalMap;


    public CopyOnWriteMap() {
        this.internalMap = new HashMap();
    }


    @Override
    public synchronized int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + (this.internalMap == null ? 0 : this.internalMap.hashCode());
        return result;
    }


    @Override
    public synchronized boolean equals(Object obj) {
        if (this == obj) {
            return true;
        }
        if (obj == null) {
            return false;
        }
        if (this.getClass() != obj.getClass()) {
            return false;
        }
        CopyOnWriteMap other = (CopyOnWriteMap) obj;
        if (this.internalMap == null) {
            if (other.internalMap != null) {
                return false;
            }
        }
        else if (!this.internalMap.equals(other.internalMap)) {
            return false;
        }
        return true;
    }


    public CopyOnWriteMap(final int initialCapacity) {
        this.internalMap = new HashMap(initialCapacity);
    }


    public CopyOnWriteMap(final Map data) {
        this.internalMap = new HashMap(data);
    }


    @Override
    public V put(final K key, final V value) {
        synchronized (this) {
            final Map newMap = new HashMap(this.internalMap);
            final V val = newMap.put(key, value);
            this.internalMap = newMap;
            return val;
        }
    }


    @Override
    public V remove(final Object key) {
        synchronized (this) {
            final Map newMap = new HashMap(this.internalMap);
            final V val = newMap.remove(key);
            this.internalMap = newMap;
            return val;
        }
    }


    @Override
    public void putAll(final Map newData) {
        synchronized (this) {
            final Map newMap = new HashMap(this.internalMap);
            newMap.putAll(newData);
            this.internalMap = newMap;
        }
    }


    @Override
    public void clear() {
        synchronized (this) {
            this.internalMap = new HashMap();
        }
    }


    @Override
    public int size() {
        return this.internalMap.size();
    }


    @Override
    public boolean isEmpty() {
        return this.internalMap.isEmpty();
    }


    @Override
    public boolean containsKey(final Object key) {
        return this.internalMap.containsKey(key);
    }


    @Override
    public boolean containsValue(final Object value) {
        return this.internalMap.containsValue(value);
    }


    @Override
    public V get(final Object key) {
        return this.internalMap.get(key);
    }


    @Override
    public Set keySet() {
        return this.internalMap.keySet();
    }


    @Override
    public Collection values() {
        return this.internalMap.values();
    }


    @Override
    public Set> entrySet() {
        return this.internalMap.entrySet();
    }


    @Override
    public synchronized String toString() {
        return "CopyOnWriteMap [internalMap=" + this.internalMap + "]";
    }


    @Override
    public Object clone() {
        try {
            return super.clone();
        }
        catch (final CloneNotSupportedException e) {
            throw new InternalError();
        }
    }
}