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     * Constructor that wraps (not copies).
070     *
071     * @param bag  the bag to decorate, must not be null
072     * @throws NullPointerException if bag is null
073     */
074    private UnmodifiableSortedBag(final SortedBag<E> bag) {
075        super(bag);
076    }
077
078    @Override
079    public boolean add(final E object) {
080        throw new UnsupportedOperationException();
081    }
082
083    @Override
084    public boolean add(final E object, final int count) {
085        throw new UnsupportedOperationException();
086    }
087
088    @Override
089    public boolean addAll(final Collection<? extends E> coll) {
090        throw new UnsupportedOperationException();
091    }
092
093    @Override
094    public void clear() {
095        throw new UnsupportedOperationException();
096    }
097
098    @Override
099    public Iterator<E> iterator() {
100        return UnmodifiableIterator.unmodifiableIterator(decorated().iterator());
101    }
102
103    /**
104     * Deserializes the collection in using a custom routine.
105     *
106     * @param in  the input stream
107     * @throws IOException if an error occurs while reading from the stream
108     * @throws ClassNotFoundException if an object read from the stream cannot be loaded
109     * @throws ClassCastException if deserialized object has wrong type
110     */
111    @SuppressWarnings("unchecked") // will throw CCE, see Javadoc
112    private void readObject(final ObjectInputStream in) throws IOException, ClassNotFoundException {
113        in.defaultReadObject();
114        setCollection((Collection<E>) in.readObject());
115    }
116
117    @Override
118    public boolean remove(final Object object) {
119        throw new UnsupportedOperationException();
120    }
121
122    @Override
123    public boolean remove(final Object object, final int count) {
124        throw new UnsupportedOperationException();
125    }
126
127    @Override
128    public boolean removeAll(final Collection<?> coll) {
129        throw new UnsupportedOperationException();
130    }
131
132    /**
133     * @since 4.4
134     */
135    @Override
136    public boolean removeIf(final Predicate<? super E> filter) {
137        throw new UnsupportedOperationException();
138    }
139
140    @Override
141    public boolean retainAll(final Collection<?> coll) {
142        throw new UnsupportedOperationException();
143    }
144
145    @Override
146    public Set<E> uniqueSet() {
147        final Set<E> set = decorated().uniqueSet();
148        return UnmodifiableSet.unmodifiableSet(set);
149    }
150
151    /**
152     * Serializes this object to an ObjectOutputStream.
153     *
154     * @param out the target ObjectOutputStream.
155     * @throws IOException thrown when an I/O errors occur writing to the target stream.
156     */
157    private void writeObject(final ObjectOutputStream out) throws IOException {
158        out.defaultWriteObject();
159        out.writeObject(decorated());
160    }
161
162}