    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}