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     * Constructor that wraps (not copies).
071     * <p>
072     * If there are any elements already in the bag being decorated, they
073     * are validated.
074     *
075     * @param bag  the bag to decorate, must not be null
076     * @param predicate  the predicate to use for validation, must not be null
077     * @throws NullPointerException if bag or predicate is null
078     * @throws IllegalArgumentException if the bag contains invalid elements
079     */
080    protected PredicatedBag(final Bag<E> bag, final Predicate<? super E> predicate) {
081        super(bag, predicate);
082    }
083
084    @Override
085    public boolean add(final E object, final int count) {
086        validate(object);
087        return decorated().add(object, count);
088    }
089
090    /**
091     * Gets the decorated bag.
092     *
093     * @return the decorated bag
094     */
095    @Override
096    protected Bag<E> decorated() {
097        return (Bag<E>) super.decorated();
098    }
099
100    @Override
101    public boolean equals(final Object object) {
102        return object == this || decorated().equals(object);
103    }
104
105    @Override
106    public int getCount(final Object object) {
107        return decorated().getCount(object);
108    }
109
110    @Override
111    public int hashCode() {
112        return decorated().hashCode();
113    }
114
115    @Override
116    public boolean remove(final Object object, final int count) {
117        return decorated().remove(object, count);
118    }
119
120    @Override
121    public Set<E> uniqueSet() {
122        return decorated().uniqueSet();
123    }
124
125}