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    /**
071     * Constructor that wraps (not copies).
072     * <p>
073     * If there are any elements already in the multiset being decorated, they
074     * are validated.
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    /**
086     * Gets the decorated multiset.
087     *
088     * @return the decorated multiset
089     */
090    @Override
091    protected MultiSet<E> decorated() {
092        return (MultiSet<E>) super.decorated();
093    }
094
095    @Override
096    public boolean equals(final Object object) {
097        return object == this || decorated().equals(object);
098    }
099
100    @Override
101    public int hashCode() {
102        return decorated().hashCode();
103    }
104
105    //-----------------------------------------------------------------------
106
107    @Override
108    public int add(final E object, final int count) {
109        validate(object);
110        return decorated().add(object, count);
111    }
112
113    @Override
114    public int remove(final Object object, final int count) {
115        return decorated().remove(object, count);
116    }
117
118    @Override
119    public int getCount(final Object object) {
120        return decorated().getCount(object);
121    }
122
123    @Override
124    public int setCount(final E object, final int count) {
125        validate(object);
126        return decorated().setCount(object, count);
127    }
128
129    @Override
130    public Set<E> uniqueSet() {
131        return decorated().uniqueSet();
132    }
133
134    @Override
135    public Set<MultiSet.Entry<E>> entrySet() {
136        return decorated().entrySet();
137    }
138
139}