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 *      https://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.multiset;
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.MultiSet;
028import org.apache.commons.collections4.SortedMultiSet;
029import org.apache.commons.collections4.Unmodifiable;
030import org.apache.commons.collections4.iterators.UnmodifiableIterator;
031import org.apache.commons.collections4.set.UnmodifiableSet;
032
033/**
034 * Decorates another {@link SortedMultiSet} to ensure it can't be altered.
035 * <p>
036 * Attempts to modify it will result in an UnsupportedOperationException.
037 * </p>
038 *
039 * @param <E> The type held in the multiset
040 * @since 4.6.0
041 */
042public final class UnmodifiableSortedMultiSet<E>
043        extends AbstractSortedMultiSetDecorator<E> implements Unmodifiable {
044
045    /** Serialization version */
046    private static final long serialVersionUID = 20260705L;
047
048    /**
049     * Factory method to create an unmodifiable multiset.
050     * <p>
051     * If the multiset passed in is already unmodifiable, it is returned.
052     * </p>
053     *
054     * @param <E>  the type of the elements in the multiset
055     * @param multiset  The multiset to decorate, may not be null
056     * @return An unmodifiable SortedMultiSet
057     * @throws NullPointerException if multiset is null
058     */
059    public static <E> SortedMultiSet<E> unmodifiableSortedMultiSet(final SortedMultiSet<? extends E> multiset) {
060        if (multiset instanceof Unmodifiable) {
061            @SuppressWarnings("unchecked") // safe to upcast
062            final SortedMultiSet<E> tmpMultiSet = (SortedMultiSet<E>) multiset;
063            return tmpMultiSet;
064        }
065        return new UnmodifiableSortedMultiSet<>(multiset);
066    }
067
068    /**
069     * Constructor that wraps (not copies).
070     *
071     * @param multiset  The multiset to decorate, may not be null
072     * @throws NullPointerException if multiset is null
073     */
074    @SuppressWarnings("unchecked") // safe to upcast
075    private UnmodifiableSortedMultiSet(final SortedMultiSet<? extends E> multiset) {
076        super((SortedMultiSet<E>) multiset);
077    }
078
079    @Override
080    public boolean add(final E object) {
081        throw new UnsupportedOperationException();
082    }
083
084    @Override
085    public int add(final E object, final int count) {
086        throw new UnsupportedOperationException();
087    }
088
089    @Override
090    public boolean addAll(final Collection<? extends E> coll) {
091        throw new UnsupportedOperationException();
092    }
093
094    @Override
095    public void clear() {
096        throw new UnsupportedOperationException();
097    }
098
099    @Override
100    public Set<MultiSet.Entry<E>> entrySet() {
101        final Set<MultiSet.Entry<E>> set = decorated().entrySet();
102        return UnmodifiableSet.unmodifiableSet(set);
103    }
104
105    @Override
106    public Iterator<E> iterator() {
107        return UnmodifiableIterator.<E>unmodifiableIterator(decorated().iterator());
108    }
109
110    /**
111     * Deserializes the collection in using a custom routine.
112     *
113     * @param in  The input stream
114     * @throws IOException Thrown if an error occurs while reading from the stream
115     * @throws ClassNotFoundException if an object read from the stream cannot be loaded
116     * @throws ClassCastException if deserialized object has wrong type
117     */
118    @SuppressWarnings("unchecked") // will throw CCE, see Javadoc
119    private void readObject(final ObjectInputStream in) throws IOException, ClassNotFoundException {
120        in.defaultReadObject();
121        setCollection((Collection<E>) in.readObject());
122    }
123
124    @Override
125    public boolean remove(final Object object) {
126        throw new UnsupportedOperationException();
127    }
128
129    @Override
130    public int remove(final Object object, final int count) {
131        throw new UnsupportedOperationException();
132    }
133
134    @Override
135    public boolean removeAll(final Collection<?> coll) {
136        throw new UnsupportedOperationException();
137    }
138
139    @Override
140    public boolean removeIf(final Predicate<? super E> filter) {
141        throw new UnsupportedOperationException();
142    }
143
144    @Override
145    public boolean retainAll(final Collection<?> coll) {
146        throw new UnsupportedOperationException();
147    }
148
149    @Override
150    public int setCount(final E object, final int count) {
151        throw new UnsupportedOperationException();
152    }
153
154    @Override
155    public Set<E> uniqueSet() {
156        final Set<E> set = decorated().uniqueSet();
157        return UnmodifiableSet.unmodifiableSet(set);
158    }
159
160    /**
161     * Serializes this object to an ObjectOutputStream.
162     *
163     * @param out The target ObjectOutputStream.
164     * @throws IOException thrown when an I/O errors occur writing to the target stream.
165     */
166    private void writeObject(final ObjectOutputStream out) throws IOException {
167        out.defaultWriteObject();
168        out.writeObject(decorated());
169    }
170
171}