/*
 *  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 org.apache.commons.collections.bag;

import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.util.Collection;
import java.util.HashMap;

import org.apache.commons.collections.Bag;

Implements Bag, using a HashMap to provide the
data storage. This is the standard implementation of a bag.

A Bag stores each object in the collection together with a
count of occurrences. Extra methods on the interface allow multiple copies
of an object to be added or removed at once. It is important to read the
interface javadoc carefully as several methods violate the
Collection interface specification.
Author:
Chuck Burdick, Stephen Colebourne
Since:
Commons Collections 3.0 (previously in main package v2.0)
Version:
$Revision: 646777 $ $Date: 2008-04-10 14:33:15 +0200 (Thu, 10 Apr 2008) $/**
 * Implements <code>Bag</code>, using a <code>HashMap</code> to provide the
 * data storage. This is the standard implementation of a bag.
 * <p>
 * A <code>Bag</code> stores each object in the collection together with a
 * count of occurrences. Extra methods on the interface allow multiple copies
 * of an object to be added or removed at once. It is important to read the
 * interface javadoc carefully as several methods violate the
 * <code>Collection</code> interface specification.
 *
 * @since Commons Collections 3.0 (previously in main package v2.0)
 * @version $Revision: 646777 $ $Date: 2008-04-10 14:33:15 +0200 (Thu, 10 Apr 2008) $
 * 
 * @author Chuck Burdick
 * @author Stephen Colebourne
 */
public class HashBag
        extends AbstractMapBag implements Bag, Serializable {

    
Serial version lock /** Serial version lock */
    private static final long serialVersionUID = -6561115435802554013L;
    
    
Constructs an empty HashBag.
/**
     * Constructs an empty <code>HashBag</code>.
     */
    public HashBag() {
        super(new HashMap());
    }

    
Constructs a bag containing all the members of the given collection.
Params:
coll –  a collection to copy into this bag/**
     * Constructs a bag containing all the members of the given collection.
     * 
     * @param coll  a collection to copy into this bag
     */
    public HashBag(Collection coll) {
        this();
        addAll(coll);
    }

    //-----------------------------------------------------------------------
    
Write the bag out using a custom routine.
/**
     * Write the bag out using a custom routine.
     */
    private void writeObject(ObjectOutputStream out) throws IOException {
        out.defaultWriteObject();
        super.doWriteObject(out);
    }

    
Read the bag in using a custom routine.
/**
     * Read the bag in using a custom routine.
     */
    private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException {
        in.defaultReadObject();
        super.doReadObject(new HashMap(), in);
    }
    
}