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