1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17 package org.apache.commons.collections4.bag;
18
19 import java.util.Comparator;
20
21 import org.apache.commons.collections4.Predicate;
22 import org.apache.commons.collections4.SortedBag;
23
24 /**
25 * Decorates another {@link SortedBag} to validate that additions
26 * match a specified predicate.
27 * <p>
28 * This bag exists to provide validation for the decorated bag.
29 * It is normally created to decorate an empty bag.
30 * If an object cannot be added to the bag, an {@link IllegalArgumentException} is thrown.
31 * </p>
32 * <p>
33 * One usage would be to ensure that no null entries are added to the bag.
34 * <pre>
35 * SortedBag bag = PredicatedSortedBag.predicatedSortedBag(new TreeBag(), NotNullPredicate.INSTANCE);
36 * </pre>
37 * <p>
38 * This class is Serializable from Commons Collections 3.1.
39 * </p>
40 *
41 * @param <E> the type of elements in this bag
42 * @since 3.0
43 */
44 public class PredicatedSortedBag<E> extends PredicatedBag<E> implements SortedBag<E> {
45
46 /** Serialization version */
47 private static final long serialVersionUID = 3448581314086406616L;
48
49 /**
50 * Factory method to create a predicated (validating) bag.
51 * <p>
52 * If there are any elements already in the bag being decorated, they
53 * are validated.
54 *
55 * @param <E> the type of the elements in the bag
56 * @param bag the bag to decorate, must not be null
57 * @param predicate the predicate to use for validation, must not be null
58 * @return a new predicated SortedBag
59 * @throws NullPointerException if bag or predicate is null
60 * @throws IllegalArgumentException if the bag contains invalid elements
61 * @since 4.0
62 */
63 public static <E> PredicatedSortedBag<E> predicatedSortedBag(final SortedBag<E> bag,
64 final Predicate<? super E> predicate) {
65 return new PredicatedSortedBag<>(bag, predicate);
66 }
67
68 /**
69 * Constructor that wraps (not copies).
70 * <p>If there are any elements already in the bag being decorated, they
71 * are validated.
72 *
73 * @param bag the bag to decorate, must not be null
74 * @param predicate the predicate to use for validation, must not be null
75 * @throws NullPointerException if bag or predicate is null
76 * @throws IllegalArgumentException if the bag contains invalid elements
77 */
78 protected PredicatedSortedBag(final SortedBag<E> bag, final Predicate<? super E> predicate) {
79 super(bag, predicate);
80 }
81
82 @Override
83 public Comparator<? super E> comparator() {
84 return decorated().comparator();
85 }
86
87 /**
88 * Gets the decorated sorted bag.
89 *
90 * @return the decorated bag
91 */
92 @Override
93 protected SortedBag<E> decorated() {
94 return (SortedBag<E>) super.decorated();
95 }
96
97 @Override
98 public E first() {
99 return decorated().first();
100 }
101
102 @Override
103 public E last() {
104 return decorated().last();
105 }
106
107 }