001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.commons.collections4.bag;
018
019import java.io.IOException;
020import java.io.ObjectInputStream;
021import java.io.ObjectOutputStream;
022import java.util.Collection;
023import java.util.Iterator;
024
025import org.apache.commons.collections4.Bag;
026
027/**
028 * Decorates another {@link Bag} to comply with the Collection contract.
029 *
030 * @since 4.0
031 * @version $Id: CollectionBag.html 972421 2015-11-14 20:00:04Z tn $
032 */
033public final class CollectionBag<E> extends AbstractBagDecorator<E> {
034
035    /** Serialization version */
036    private static final long serialVersionUID = -2560033712679053143L;
037
038    /**
039     * Factory method to create a bag that complies to the Collection contract.
040     *
041     * @param <E> the type of the elements in the bag
042     * @param bag  the bag to decorate, must not be null
043     * @return a Bag that complies to the Collection contract
044     * @throws IllegalArgumentException if bag is null
045     */
046    public static <E> Bag<E> collectionBag(final Bag<E> bag) {
047        return new CollectionBag<E>(bag);
048    }
049
050    //-----------------------------------------------------------------------
051    /**
052     * Constructor that wraps (not copies).
053     *
054     * @param bag  the bag to decorate, must not be null
055     * @throws IllegalArgumentException if bag is null
056     */
057    public CollectionBag(final Bag<E> bag) {
058        super(bag);
059    }
060
061    //-----------------------------------------------------------------------
062    /**
063     * Write the collection out using a custom routine.
064     *
065     * @param out  the output stream
066     * @throws IOException
067     */
068    private void writeObject(final ObjectOutputStream out) throws IOException {
069        out.defaultWriteObject();
070        out.writeObject(decorated());
071    }
072
073    /**
074     * Read the collection in using a custom routine.
075     *
076     * @param in  the input stream
077     * @throws IOException
078     * @throws ClassNotFoundException
079     * @throws ClassCastException if deserialised object has wrong type
080     */
081    @SuppressWarnings("unchecked") // will throw CCE, see Javadoc
082    private void readObject(final ObjectInputStream in) throws IOException, ClassNotFoundException {
083        in.defaultReadObject();
084        setCollection((Collection<E>) in.readObject());
085    }
086
087    //-----------------------------------------------------------------------
088    // Collection interface
089    //-----------------------------------------------------------------------
090
091    @Override
092    public boolean containsAll(final Collection<?> coll) {
093        final Iterator<?> e = coll.iterator();
094        while (e.hasNext()) {
095            if(!contains(e.next())) {
096                return false;
097            }
098        }
099        return true;
100    }
101
102    @Override
103    public boolean add(final E object) {
104        return add(object, 1);
105    }
106
107    @Override
108    public boolean addAll(final Collection<? extends E> coll) {
109        boolean changed = false;
110        final Iterator<? extends E> i = coll.iterator();
111        while (i.hasNext()) {
112            final boolean added = add(i.next(), 1);
113            changed = changed || added;
114        }
115        return changed;
116    }
117
118    @Override
119    public boolean remove(final Object object) {
120        return remove(object, 1);
121    }
122
123    @Override
124    public boolean removeAll(final Collection<?> coll) {
125        if (coll != null) {
126            boolean result = false;
127            final Iterator<?> i = coll.iterator();
128            while (i.hasNext()) {
129                final Object obj = i.next();
130                final boolean changed = remove(obj, getCount(obj));
131                result = result || changed;
132            }
133            return result;
134        } else {
135            // let the decorated bag handle the case of null argument
136            return decorated().removeAll(null);
137        }
138    }
139
140    @Override
141    public boolean retainAll(final Collection<?> coll) {
142        if (coll != null) {
143            boolean modified = false;
144            final Iterator<E> e = iterator();
145            while (e.hasNext()) {
146                if (!coll.contains(e.next())) {
147                    e.remove();
148                    modified = true;
149                }
150            }
151            return modified;
152        } else {
153            // let the decorated bag handle the case of null argument
154            return decorated().retainAll(null);
155        }
156    }
157
158    //-----------------------------------------------------------------------
159    // Bag interface
160    //-----------------------------------------------------------------------
161
162    @Override
163    public boolean add(final E object, final int count) {
164        decorated().add(object, count);
165        return true;
166    }
167
168}