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.ToDoubleBiFunction;
21
22 /**
23 * A functional interface like {@link ToDoubleBiFunction} that declares a {@link Throwable}.
24 *
25 * @param <T> the type of the first argument to the function
26 * @param <U> the type of the second argument to the function
27 * @param <E> The kind of thrown exception or error.
28 * @since 3.11
29 */
30 @FunctionalInterface
31 public interface FailableToDoubleBiFunction<T, U, E extends Throwable> {
32
33 /** NOP singleton */
34 @SuppressWarnings("rawtypes")
35 FailableToDoubleBiFunction NOP = (t, u) -> 0d;
36
37 /**
38 * Gets the NOP singleton.
39 *
40 * @param <T> the type of the first argument to the function
41 * @param <U> the type of the second argument to the function
42 * @param <E> The kind of thrown exception or error.
43 * @return The NOP singleton.
44 */
45 @SuppressWarnings("unchecked")
46 static <T, U, E extends Throwable> FailableToDoubleBiFunction<T, U, E> nop() {
47 return NOP;
48 }
49
50 /**
51 * Applies this function to the given arguments.
52 *
53 * @param t the first function argument
54 * @param u the second function argument
55 * @return the function result
56 * @throws E Thrown when the function fails.
57 */
58 double applyAsDouble(T t, U u) throws E;
59 }