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.bag;
018
019import java.util.Set;
020
021import org.apache.commons.collections4.Bag;
022import org.apache.commons.collections4.Predicate;
023import org.apache.commons.collections4.collection.PredicatedCollection;
024
025/**
026 * Decorates another {@link Bag} to validate that additions
027 * match a specified predicate.
028 * <p>
029 * This bag exists to provide validation for the decorated bag.
030 * It is normally created to decorate an empty bag.
031 * If an object cannot be added to the bag, an {@link IllegalArgumentException} is thrown.
032 * </p>
033 * <p>
034 * One usage would be to ensure that no null entries are added to the bag.
035 * </p>
036 * <pre>
037 * Bag bag = PredicatedBag.predicatedBag(new HashBag(), NotNullPredicate.INSTANCE);
038 * </pre>
039 * <p>
040 * This class is Serializable from Commons Collections 3.1.
041 * </p>
042 *
043 * @param <E> the type of elements in this bag
044 * @since 3.0
045 */
046public class PredicatedBag<E> extends PredicatedCollection<E> implements Bag<E> {
047
048    /** Serialization version */
049    private static final long serialVersionUID = -2575833140344736876L;
050
051    /**
052     * Factory method to create a predicated (validating) bag.
053     * <p>
054     * If there are any elements already in the bag being decorated, they
055     * are validated.
056     *
057     * @param <E> the type of the elements in the bag
058     * @param bag  the bag to decorate, must not be null
059     * @param predicate  the predicate to use for validation, must not be null
060     * @return a new predicated Bag
061     * @throws NullPointerException if bag or predicate is null
062     * @throws IllegalArgumentException if the bag contains invalid elements
063     * @since 4.0
064     */
065    public static <E> PredicatedBag<E> predicatedBag(final Bag<E> bag, final Predicate<? super E> predicate) {
066        return new PredicatedBag<>(bag, predicate);
067    }
068
069    //-----------------------------------------------------------------------
070    /**
071     * Constructor that wraps (not copies).
072     * <p>
073     * If there are any elements already in the bag being decorated, they
074     * are validated.
075     *
076     * @param bag  the bag to decorate, must not be null
077     * @param predicate  the predicate to use for validation, must not be null
078     * @throws NullPointerException if bag or predicate is null
079     * @throws IllegalArgumentException if the bag contains invalid elements
080     */
081    protected PredicatedBag(final Bag<E> bag, final Predicate<? super E> predicate) {
082        super(bag, predicate);
083    }
084
085    /**
086     * Gets the decorated bag.
087     *
088     * @return the decorated bag
089     */
090    @Override
091    protected Bag<E> decorated() {
092        return (Bag<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 boolean add(final E object, final int count) {
109        validate(object);
110        return decorated().add(object, count);
111    }
112
113    @Override
114    public boolean remove(final Object object, final int count) {
115        return decorated().remove(object, count);
116    }
117
118    @Override
119    public Set<E> uniqueSet() {
120        return decorated().uniqueSet();
121    }
122
123    @Override
124    public int getCount(final Object object) {
125        return decorated().getCount(object);
126    }
127
128}