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 * <p>
033 * One usage would be to ensure that no null entries are added to the bag.
034 * <pre>
035 * SortedBag bag = PredicatedSortedBag.predicatedSortedBag(new TreeBag(), NotNullPredicate.INSTANCE);
036 * </pre>
037 * <p>
038 * This class is Serializable from Commons Collections 3.1.
039 * </p>
040 *
041 * @param <E> the type of elements in this bag
042 * @since 3.0
043 */
044public class PredicatedSortedBag<E> extends PredicatedBag<E> implements SortedBag<E> {
045
046    /** Serialization version */
047    private static final long serialVersionUID = 3448581314086406616L;
048
049    /**
050     * Factory method to create a predicated (validating) bag.
051     * <p>
052     * If there are any elements already in the bag being decorated, they
053     * are validated.
054     *
055     * @param <E> the type of the elements in the bag
056     * @param bag  the bag to decorate, must not be null
057     * @param predicate  the predicate to use for validation, must not be null
058     * @return a new predicated SortedBag
059     * @throws NullPointerException if bag or predicate is null
060     * @throws IllegalArgumentException if the bag contains invalid elements
061     * @since 4.0
062     */
063    public static <E> PredicatedSortedBag<E> predicatedSortedBag(final SortedBag<E> bag,
064                                                                 final Predicate<? super E> predicate) {
065        return new PredicatedSortedBag<>(bag, predicate);
066    }
067
068    /**
069     * Constructor that wraps (not copies).
070     * <p>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 PredicatedSortedBag(final SortedBag<E> bag, final Predicate<? super E> predicate) {
079        super(bag, predicate);
080    }
081
082    @Override
083    public Comparator<? super E> comparator() {
084        return decorated().comparator();
085    }
086
087    /**
088     * Gets the decorated sorted bag.
089     *
090     * @return the decorated bag
091     */
092    @Override
093    protected SortedBag<E> decorated() {
094        return (SortedBag<E>) super.decorated();
095    }
096
097    @Override
098    public E first() {
099        return decorated().first();
100    }
101
102    @Override
103    public E last() {
104        return decorated().last();
105    }
106
107}