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 * https://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
18 package org.apache.commons.lang3.function;
19
20 import java.util.function.Predicate;
21
22 /**
23 * Factory for {@link Predicate}.
24 *
25 * @since 3.18.0
26 */
27 public class Predicates {
28
29 private static final Predicate<?> TRUE = t -> true;
30 private static final Predicate<?> FALSE = t -> false;
31
32 /**
33 * Gets the Predicate singleton that always returns false.
34 *
35 * @param <T> the type of the input to the predicate.
36 * @return the Predicate singleton.
37 */
38 @SuppressWarnings("unchecked")
39 // method name cannot be "false".
40 public static <T> Predicate<T> falsePredicate() {
41 return (Predicate<T>) FALSE;
42 }
43
44 /**
45 * Gets the Predicate singleton that always returns true.
46 *
47 * @param <T> the type of the input to the predicate.
48 * @return the Predicate singleton.
49 */
50 @SuppressWarnings("unchecked")
51 // method name cannot be "true".
52 public static <T> Predicate<T> truePredicate() {
53 return (Predicate<T>) TRUE;
54 }
55
56 /**
57 * No instances needed.
58 */
59 private Predicates() {
60 // empty
61 }
62 }