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;
024import java.util.Set;
025
026import org.apache.commons.collections4.SortedBag;
027import org.apache.commons.collections4.Unmodifiable;
028import org.apache.commons.collections4.iterators.UnmodifiableIterator;
029import org.apache.commons.collections4.set.UnmodifiableSet;
030
031/**
032 * Decorates another {@link SortedBag} to ensure it can't be altered.
033 * <p>
034 * This class is Serializable from Commons Collections 3.1.
035 * <p>
036 * Attempts to modify it will result in an UnsupportedOperationException.
037 *
038 * @since 3.0
039 * @version $Id: UnmodifiableSortedBag.html 887892 2013-11-24 13:43:45Z tn $
040 */
041public final class UnmodifiableSortedBag<E>
042        extends AbstractSortedBagDecorator<E> implements Unmodifiable {
043
044    /** Serialization version */
045    private static final long serialVersionUID = -3190437252665717841L;
046
047    /**
048     * Factory method to create an unmodifiable bag.
049     * <p>
050     * If the bag passed in is already unmodifiable, it is returned.
051     *
052     * @param <E> the type of the elements in the bag
053     * @param bag  the bag to decorate, must not be null
054     * @return an unmodifiable SortedBag
055     * @throws IllegalArgumentException if bag is null
056     * @since 4.0
057     */
058    public static <E> SortedBag<E> unmodifiableSortedBag(final SortedBag<E> bag) {
059        if (bag instanceof Unmodifiable) {
060            return bag;
061        }
062        return new UnmodifiableSortedBag<E>(bag);
063    }
064
065    //-----------------------------------------------------------------------
066    /**
067     * Constructor that wraps (not copies).
068     *
069     * @param bag  the bag to decorate, must not be null
070     * @throws IllegalArgumentException if bag is null
071     */
072    private UnmodifiableSortedBag(final SortedBag<E> bag) {
073        super(bag);
074    }
075
076    //-----------------------------------------------------------------------
077    /**
078     * Write the collection out using a custom routine.
079     *
080     * @param out  the output stream
081     * @throws IOException
082     */
083    private void writeObject(final ObjectOutputStream out) throws IOException {
084        out.defaultWriteObject();
085        out.writeObject(decorated());
086    }
087
088    /**
089     * Read the collection in using a custom routine.
090     *
091     * @param in  the input stream
092     * @throws IOException
093     * @throws ClassNotFoundException
094     * @throws ClassCastException if deserialised object has wrong type
095     */
096    @SuppressWarnings("unchecked") // will throw CCE, see Javadoc
097    private void readObject(final ObjectInputStream in) throws IOException, ClassNotFoundException {
098        in.defaultReadObject();
099        setCollection((Collection<E>) in.readObject());
100    }
101
102    //-----------------------------------------------------------------------
103    @Override
104    public Iterator<E> iterator() {
105        return UnmodifiableIterator.unmodifiableIterator(decorated().iterator());
106    }
107
108    @Override
109    public boolean add(final E object) {
110        throw new UnsupportedOperationException();
111    }
112
113    @Override
114    public boolean addAll(final Collection<? extends E> coll) {
115        throw new UnsupportedOperationException();
116    }
117
118    @Override
119    public void clear() {
120        throw new UnsupportedOperationException();
121    }
122
123    @Override
124    public boolean remove(final Object object) {
125        throw new UnsupportedOperationException();
126    }
127
128    @Override
129    public boolean removeAll(final Collection<?> coll) {
130        throw new UnsupportedOperationException();
131    }
132
133    @Override
134    public boolean retainAll(final Collection<?> coll) {
135        throw new UnsupportedOperationException();
136    }
137
138    //-----------------------------------------------------------------------
139    @Override
140    public boolean add(final E object, final int count) {
141        throw new UnsupportedOperationException();
142    }
143
144    @Override
145    public boolean remove(final Object object, final int count) {
146        throw new UnsupportedOperationException();
147    }
148
149    @Override
150    public Set<E> uniqueSet() {
151        final Set<E> set = decorated().uniqueSet();
152        return UnmodifiableSet.unmodifiableSet(set);
153    }
154
155}