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;
025import java.util.function.Predicate;
026
027import org.apache.commons.collections4.SortedBag;
028import org.apache.commons.collections4.Unmodifiable;
029import org.apache.commons.collections4.iterators.UnmodifiableIterator;
030import org.apache.commons.collections4.set.UnmodifiableSet;
031
032/**
033 * Decorates another {@link SortedBag} to ensure it can't be altered.
034 * <p>
035 * This class is Serializable from Commons Collections 3.1.
036 * </p>
037 * <p>
038 * Attempts to modify it will result in an UnsupportedOperationException.
039 * </p>
040 *
041 * @param <E> the type of elements in this bag
042 * @since 3.0
043 */
044public final class UnmodifiableSortedBag<E>
045        extends AbstractSortedBagDecorator<E> implements Unmodifiable {
046
047    /** Serialization version */
048    private static final long serialVersionUID = -3190437252665717841L;
049
050    /**
051     * Factory method to create an unmodifiable bag.
052     * <p>
053     * If the bag passed in is already unmodifiable, it is returned.
054     *
055     * @param <E> the type of the elements in the bag
056     * @param bag  the bag to decorate, must not be null
057     * @return an unmodifiable SortedBag
058     * @throws NullPointerException if bag is null
059     * @since 4.0
060     */
061    public static <E> SortedBag<E> unmodifiableSortedBag(final SortedBag<E> bag) {
062        if (bag instanceof Unmodifiable) {
063            return bag;
064        }
065        return new UnmodifiableSortedBag<>(bag);
066    }
067
068    //-----------------------------------------------------------------------
069    /**
070     * Constructor that wraps (not copies).
071     *
072     * @param bag  the bag to decorate, must not be null
073     * @throws NullPointerException if bag is null
074     */
075    private UnmodifiableSortedBag(final SortedBag<E> bag) {
076        super(bag);
077    }
078
079    //-----------------------------------------------------------------------
080    /**
081     * Write the collection out using a custom routine.
082     *
083     * @param out  the output stream
084     * @throws IOException if an error occurs while writing to the stream
085     */
086    private void writeObject(final ObjectOutputStream out) throws IOException {
087        out.defaultWriteObject();
088        out.writeObject(decorated());
089    }
090
091    /**
092     * Read the collection in using a custom routine.
093     *
094     * @param in  the input stream
095     * @throws IOException if an error occurs while reading from the stream
096     * @throws ClassNotFoundException if an object read from the stream can not be loaded
097     * @throws ClassCastException if deserialised object has wrong type
098     */
099    @SuppressWarnings("unchecked") // will throw CCE, see Javadoc
100    private void readObject(final ObjectInputStream in) throws IOException, ClassNotFoundException {
101        in.defaultReadObject();
102        setCollection((Collection<E>) in.readObject());
103    }
104
105    //-----------------------------------------------------------------------
106    @Override
107    public Iterator<E> iterator() {
108        return UnmodifiableIterator.unmodifiableIterator(decorated().iterator());
109    }
110
111    @Override
112    public boolean add(final E object) {
113        throw new UnsupportedOperationException();
114    }
115
116    @Override
117    public boolean addAll(final Collection<? extends E> coll) {
118        throw new UnsupportedOperationException();
119    }
120
121    @Override
122    public void clear() {
123        throw new UnsupportedOperationException();
124    }
125
126    @Override
127    public boolean remove(final Object object) {
128        throw new UnsupportedOperationException();
129    }
130
131    /**
132     * @since 4.4
133     */
134    @Override
135    public boolean removeIf(Predicate<? super E> filter) {
136        throw new UnsupportedOperationException();
137    }
138
139    @Override
140    public boolean removeAll(final Collection<?> coll) {
141        throw new UnsupportedOperationException();
142    }
143
144    @Override
145    public boolean retainAll(final Collection<?> coll) {
146        throw new UnsupportedOperationException();
147    }
148
149    //-----------------------------------------------------------------------
150    @Override
151    public boolean add(final E object, final int count) {
152        throw new UnsupportedOperationException();
153    }
154
155    @Override
156    public boolean remove(final Object object, final int count) {
157        throw new UnsupportedOperationException();
158    }
159
160    @Override
161    public Set<E> uniqueSet() {
162        final Set<E> set = decorated().uniqueSet();
163        return UnmodifiableSet.unmodifiableSet(set);
164    }
165
166}