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.Comparator;
020
021import org.apache.commons.collections4.Predicate;
022import org.apache.commons.collections4.SortedBag;
023
024/**
025 * Decorates another {@link SortedBag} to validate that additions
026 * match a specified predicate.
027 * <p>
028 * This bag exists to provide validation for the decorated bag.
029 * It is normally created to decorate an empty bag.
030 * If an object cannot be added to the bag, an {@link IllegalArgumentException} is thrown.
031 * <p>
032 * One usage would be to ensure that no null entries are added to the bag.
033 * <pre>
034 * SortedBag bag = PredicatedSortedBag.predicatedSortedBag(new TreeBag(), NotNullPredicate.INSTANCE);
035 * </pre>
036 * <p>
037 * This class is Serializable from Commons Collections 3.1.
038 *
039 * @param <E> the type of elements in this bag
040 * @since 3.0
041 */
042public class PredicatedSortedBag<E> extends PredicatedBag<E> implements SortedBag<E> {
043
044    /** Serialization version */
045    private static final long serialVersionUID = 3448581314086406616L;
046
047    /**
048     * Factory method to create a predicated (validating) bag.
049     * <p>
050     * If there are any elements already in the bag being decorated, they
051     * are validated.
052     *
053     * @param <E> the type of the elements in the bag
054     * @param bag  the bag to decorate, must not be null
055     * @param predicate  the predicate to use for validation, must not be null
056     * @return a new predicated SortedBag
057     * @throws NullPointerException if bag or predicate is null
058     * @throws IllegalArgumentException if the bag contains invalid elements
059     * @since 4.0
060     */
061    public static <E> PredicatedSortedBag<E> predicatedSortedBag(final SortedBag<E> bag,
062                                                                 final Predicate<? super E> predicate) {
063        return new PredicatedSortedBag<>(bag, predicate);
064    }
065
066    //-----------------------------------------------------------------------
067    /**
068     * Constructor that wraps (not copies).
069     * <p>If there are any elements already in the bag being decorated, they
070     * are validated.
071     *
072     * @param bag  the bag to decorate, must not be null
073     * @param predicate  the predicate to use for validation, must not be null
074     * @throws NullPointerException if bag or predicate is null
075     * @throws IllegalArgumentException if the bag contains invalid elements
076     */
077    protected PredicatedSortedBag(final SortedBag<E> bag, final Predicate<? super E> predicate) {
078        super(bag, predicate);
079    }
080
081    /**
082     * Gets the decorated sorted bag.
083     *
084     * @return the decorated bag
085     */
086    @Override
087    protected SortedBag<E> decorated() {
088        return (SortedBag<E>) super.decorated();
089    }
090
091    //-----------------------------------------------------------------------
092
093    @Override
094    public E first() {
095        return decorated().first();
096    }
097
098    @Override
099    public E last() {
100        return decorated().last();
101    }
102
103    @Override
104    public Comparator<? super E> comparator() {
105        return decorated().comparator();
106    }
107
108}