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.collections.functors;
18
19 import java.io.Serializable;
20
21 import org.apache.commons.collections.FunctorException;
22 import org.apache.commons.collections.Predicate;
23
24 /**
25 * Predicate implementation that throws an exception if the input is null.
26 *
27 * @since 3.0
28 * @version $Id: NullIsExceptionPredicate.java 1429905 2013-01-07 17:15:14Z ggregory $
29 */
30 public final class NullIsExceptionPredicate<T> implements Predicate<T>, PredicateDecorator<T>, Serializable {
31
32 /** Serial version UID */
33 private static final long serialVersionUID = 3243449850504576071L;
34
35 /** The predicate to decorate */
36 private final Predicate<? super T> iPredicate;
37
38 /**
39 * Factory to create the null exception predicate.
40 *
41 * @param <T> the type that the predicate queries
42 * @param predicate the predicate to decorate, not null
43 * @return the predicate
44 * @throws IllegalArgumentException if the predicate is null
45 */
46 public static <T> Predicate<T> nullIsExceptionPredicate(final Predicate<? super T> predicate) {
47 if (predicate == null) {
48 throw new IllegalArgumentException("Predicate must not be null");
49 }
50 return new NullIsExceptionPredicate<T>(predicate);
51 }
52
53 /**
54 * Constructor that performs no validation.
55 * Use <code>getInstance</code> if you want that.
56 *
57 * @param predicate the predicate to call after the null check
58 */
59 public NullIsExceptionPredicate(final Predicate<? super T> predicate) {
60 super();
61 iPredicate = predicate;
62 }
63
64 /**
65 * Evaluates the predicate returning the result of the decorated predicate
66 * once a null check is performed.
67 *
68 * @param object the input object
69 * @return true if decorated predicate returns true
70 * @throws FunctorException if input is null
71 */
72 public boolean evaluate(final T object) {
73 if (object == null) {
74 throw new FunctorException("Input Object must not be null");
75 }
76 return iPredicate.evaluate(object);
77 }
78
79 /**
80 * Gets the predicate being decorated.
81 *
82 * @return the predicate as the only element in an array
83 * @since 3.1
84 */
85 @SuppressWarnings("unchecked")
86 public Predicate<? super T>[] getPredicates() {
87 return new Predicate[] { iPredicate };
88 }
89
90 }