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 /**
21 * A functional interface like a {@code ToBooleanFunction} that declares a {@link Throwable}.
22 *
23 * @param <T> the type of the argument to the function
24 * @param <E> The kind of thrown exception or error.
25 * @since 3.18
26 */
27 @FunctionalInterface
28 public interface FailableToBooleanFunction<T, E extends Throwable> {
29
30 /** NOP singleton */
31 @SuppressWarnings("rawtypes")
32 FailableToBooleanFunction NOP = t -> false;
33
34 /**
35 * Gets the NOP singleton.
36 *
37 * @param <T> the type of the argument to the function
38 * @param <E> The kind of thrown exception or error.
39 * @return The NOP singleton.
40 */
41 @SuppressWarnings("unchecked")
42 static <T, E extends Throwable> FailableToBooleanFunction<T, E> nop() {
43 return NOP;
44 }
45
46 /**
47 * Applies this function to the given arguments.
48 *
49 * @param t the first function argument
50 * @return the function result
51 * @throws E Thrown when the function fails.
52 */
53 boolean applyAsBoolean(T t) throws E;
54 }