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.functors;
18
19 import java.io.Serializable;
20 import java.util.Objects;
21
22 import org.apache.commons.collections4.FunctorException;
23 import org.apache.commons.collections4.Predicate;
24
25 /**
26 * Predicate implementation that throws an exception if the input is null.
27 *
28 * @since 3.0
29 */
30 public final class NullIsExceptionPredicate<T> implements PredicateDecorator<T>, Serializable {
31
32 /** Serial version UID */
33 private static final long serialVersionUID = 3243449850504576071L;
34
35 /**
36 * Factory to create the null exception predicate.
37 *
38 * @param <T> the type that the predicate queries
39 * @param predicate the predicate to decorate, not null
40 * @return the predicate
41 * @throws NullPointerException if the predicate is null
42 */
43 public static <T> Predicate<T> nullIsExceptionPredicate(final Predicate<? super T> predicate) {
44 return new NullIsExceptionPredicate<>(Objects.requireNonNull(predicate, "predicate"));
45 }
46
47 /** The predicate to decorate */
48 private final Predicate<? super T> iPredicate;
49
50 /**
51 * Constructor that performs no validation.
52 * Use {@code nullIsExceptionPredicate} if you want that.
53 *
54 * @param predicate the predicate to call after the null check
55 */
56 public NullIsExceptionPredicate(final Predicate<? super T> predicate) {
57 iPredicate = predicate;
58 }
59
60 /**
61 * Evaluates the predicate returning the result of the decorated predicate
62 * once a null check is performed.
63 *
64 * @param object the input object
65 * @return true if decorated predicate returns true
66 * @throws FunctorException if input is null
67 */
68 @Override
69 public boolean evaluate(final T object) {
70 if (object == null) {
71 throw new FunctorException("Input Object must not be null");
72 }
73 return iPredicate.evaluate(object);
74 }
75
76 /**
77 * Gets the predicate being decorated.
78 *
79 * @return the predicate as the only element in an array
80 * @since 3.1
81 */
82 @Override
83 @SuppressWarnings("unchecked")
84 public Predicate<? super T>[] getPredicates() {
85 return new Predicate[] { iPredicate };
86 }
87
88 }