/*
 * 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.collections4.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;

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. 
Type parameters:
<E> – the type of elements in this bag
Since:
3.0 (previously in main package v2.0)/**
 * Implements {@code Bag}, using a {@link HashMap} to provide the
 * data storage. This is the standard implementation of a bag.
 * <p>
 * A {@code 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
 * {@link Collection} interface specification.
 * </p>
 *
 * @param <E> the type of elements in this bag
 * @since 3.0 (previously in main package v2.0)
 */
public class HashBag<E> extends AbstractMapBag<E> implements Serializable {

    
Serial version lock /** Serial version lock */
    private static final long serialVersionUID = -6561115435802554013L;

    
Constructs an empty HashBag. /**
     * Constructs an empty {@link HashBag}.
     */
    public HashBag() {
        super(new HashMap<E, MutableInteger>());
    }

    
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(final Collection<? extends E> coll) {
        this();
        addAll(coll);
    }

    //-----------------------------------------------------------------------
    
Write the bag out using a custom routine.
Params:
out –  the output stream
Throws:
IOException – if an error occurs while writing to the stream/**
     * Write the bag out using a custom routine.
     *
     * @param out  the output stream
     * @throws IOException if an error occurs while writing to the stream
     */
    private void writeObject(final ObjectOutputStream out) throws IOException {
        out.defaultWriteObject();
        super.doWriteObject(out);
    }

    
Read the bag in using a custom routine.
Params:
in –  the input stream
Throws:
IOException – if an error occurs while reading from the stream
ClassNotFoundException – if an object read from the stream can not be loaded/**
     * Read the bag in using a custom routine.
     *
     * @param in  the input stream
     * @throws IOException if an error occurs while reading from the stream
     * @throws ClassNotFoundException if an object read from the stream can not be loaded
     */
    private void readObject(final ObjectInputStream in) throws IOException, ClassNotFoundException {
        in.defaultReadObject();
        super.doReadObject(new HashMap<E, MutableInteger>(), in);
    }

}