    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.multiset;
    018
    019import java.util.Set;
    020
    021import org.apache.commons.collections4.MultiSet;
    022import org.apache.commons.collections4.Predicate;
    023import org.apache.commons.collections4.collection.PredicatedCollection;
    024
    025/**
    026 * Decorates another {@link MultiSet} to validate that additions
    027 * match a specified predicate.
    028 * <p>
    029 * This multiset exists to provide validation for the decorated multiset.
    030 * It is normally created to decorate an empty multiset.
    031 * If an object cannot be added to the multiset, an {@link IllegalArgumentException}
    032 * is thrown.
    033 * </p>
    034 * <p>
    035 * One usage would be to ensure that no null entries are added to the multiset.
    036 * </p>
    037 * <pre>
    038 * MultiSet&lt;E&gt; set =
    039 *      PredicatedMultiSet.predicatedMultiSet(new HashMultiSet&lt;E&gt;(),
    040 *                                            NotNullPredicate.notNullPredicate());
    041 * </pre>
    042 *
    043 * @param <E> the type held in the multiset
    044 * @since 4.1
    045 */
    046public class PredicatedMultiSet<E> extends PredicatedCollection<E> implements MultiSet<E> {
    047
    048    /** Serialization version */
    049    private static final long serialVersionUID = 20150629L;
    050
    051    /**
    052     * Factory method to create a predicated (validating) multiset.
    053     * <p>
    054     * If there are any elements already in the multiset being decorated, they
    055     * are validated.
    056     *
    057     * @param <E> the type of the elements in the multiset
    058     * @param multiset  the multiset to decorate, must not be null
    059     * @param predicate  the predicate to use for validation, must not be null
    060     * @return a new predicated MultiSet
    061     * @throws NullPointerException if multiset or predicate is null
    062     * @throws IllegalArgumentException if the multiset contains invalid elements
    063     */
    064    public static <E> PredicatedMultiSet<E> predicatedMultiSet(final MultiSet<E> multiset,
    065                                                               final Predicate<? super E> predicate) {
    066        return new PredicatedMultiSet<>(multiset, predicate);
    067    }
    068
    069    /**
    070     * Constructor that wraps (not copies).
    071     * <p>
    072     * If there are any elements already in the multiset being decorated, they
    073     * are validated.
    074     * </p>
    075     *
    076     * @param multiset  the multiset to decorate, must not be null
    077     * @param predicate  the predicate to use for validation, must not be null
    078     * @throws NullPointerException if multiset or predicate is null
    079     * @throws IllegalArgumentException if the multiset contains invalid elements
    080     */
    081    protected PredicatedMultiSet(final MultiSet<E> multiset, final Predicate<? super E> predicate) {
    082        super(multiset, predicate);
    083    }
    084
    085    @Override
    086    public int add(final E object, final int count) {
    087        validate(object);
    088        return decorated().add(object, count);
    089    }
    090
    091    /**
    092     * Gets the decorated multiset.
    093     *
    094     * @return the decorated multiset
    095     */
    096    @Override
    097    protected MultiSet<E> decorated() {
    098        return (MultiSet<E>) super.decorated();
    099    }
    100
    101    @Override
    102    public Set<MultiSet.Entry<E>> entrySet() {
    103        return decorated().entrySet();
    104    }
    105
    106    @Override
    107    public boolean equals(final Object object) {
    108        return object == this || decorated().equals(object);
    109    }
    110
    111    @Override
    112    public int getCount(final Object object) {
    113        return decorated().getCount(object);
    114    }
    115
    116    @Override
    117    public int hashCode() {
    118        return decorated().hashCode();
    119    }
    120
    121    @Override
    122    public int remove(final Object object, final int count) {
    123        return decorated().remove(object, count);
    124    }
    125
    126    @Override
    127    public int setCount(final E object, final int count) {
    128        validate(object);
    129        return decorated().setCount(object, count);
    130    }
    131
    132    @Override
    133    public Set<E> uniqueSet() {
    134        return decorated().uniqueSet();
    135    }
    136
    137}