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 * One usage would be to ensure that no null entries are added to the bag.
034 * <pre>
035 * Bag bag = PredicatedBag.predicatedBag(new HashBag(), NotNullPredicate.INSTANCE);
036 * </pre>
037 * <p>
038 * This class is Serializable from Commons Collections 3.1.
039 *
040 * @param <E> the type of elements in this bag
041 * @since 3.0
042 */
043public class PredicatedBag<E> extends PredicatedCollection<E> implements Bag<E> {
044
045    /** Serialization version */
046    private static final long serialVersionUID = -2575833140344736876L;
047
048    /**
049     * Factory method to create a predicated (validating) bag.
050     * <p>
051     * If there are any elements already in the bag being decorated, they
052     * are validated.
053     *
054     * @param <E> the type of the elements in the bag
055     * @param bag  the bag to decorate, must not be null
056     * @param predicate  the predicate to use for validation, must not be null
057     * @return a new predicated Bag
058     * @throws NullPointerException if bag or predicate is null
059     * @throws IllegalArgumentException if the bag contains invalid elements
060     * @since 4.0
061     */
062    public static <E> PredicatedBag<E> predicatedBag(final Bag<E> bag, final Predicate<? super E> predicate) {
063        return new PredicatedBag<>(bag, predicate);
064    }
065
066    //-----------------------------------------------------------------------
067    /**
068     * Constructor that wraps (not copies).
069     * <p>
070     * If there are any elements already in the bag being decorated, they
071     * are validated.
072     *
073     * @param bag  the bag to decorate, must not be null
074     * @param predicate  the predicate to use for validation, must not be null
075     * @throws NullPointerException if bag or predicate is null
076     * @throws IllegalArgumentException if the bag contains invalid elements
077     */
078    protected PredicatedBag(final Bag<E> bag, final Predicate<? super E> predicate) {
079        super(bag, predicate);
080    }
081
082    /**
083     * Gets the decorated bag.
084     *
085     * @return the decorated bag
086     */
087    @Override
088    protected Bag<E> decorated() {
089        return (Bag<E>) super.decorated();
090    }
091
092    @Override
093    public boolean equals(final Object object) {
094        return object == this || decorated().equals(object);
095    }
096
097    @Override
098    public int hashCode() {
099        return decorated().hashCode();
100    }
101
102    //-----------------------------------------------------------------------
103
104    @Override
105    public boolean add(final E object, final int count) {
106        validate(object);
107        return decorated().add(object, count);
108    }
109
110    @Override
111    public boolean remove(final Object object, final int count) {
112        return decorated().remove(object, count);
113    }
114
115    @Override
116    public Set<E> uniqueSet() {
117        return decorated().uniqueSet();
118    }
119
120    @Override
121    public int getCount(final Object object) {
122        return decorated().getCount(object);
123    }
124
125}