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
18 package org.apache.commons.lang3.function;
19
20 import java.util.Objects;
21 import java.util.function.IntUnaryOperator;
22
23 /**
24 * A functional interface like {@link IntUnaryOperator} that declares a {@link Throwable}.
25 *
26 * @param <E> The kind of thrown exception or error.
27 * @since 3.11
28 */
29 public interface FailableIntUnaryOperator<E extends Throwable> {
30
31 /** NOP singleton */
32 @SuppressWarnings("rawtypes")
33 FailableIntUnaryOperator NOP = t -> 0;
34
35 /**
36 * Returns a unary operator that always returns its input argument.
37 *
38 * @param <E> The kind of thrown exception or error.
39 * @return a unary operator that always returns its input argument
40 */
41 static <E extends Throwable> FailableIntUnaryOperator<E> identity() {
42 return t -> t;
43 }
44
45 /**
46 * Returns The NOP singleton.
47 *
48 * @param <E> The kind of thrown exception or error.
49 * @return The NOP singleton.
50 */
51 @SuppressWarnings("unchecked")
52 static <E extends Throwable> FailableIntUnaryOperator<E> nop() {
53 return NOP;
54 }
55
56 /**
57 * Returns a composed {@link FailableDoubleUnaryOperator} like {@link IntUnaryOperator#andThen(IntUnaryOperator)}.
58 *
59 * @param after the operator to apply after this one.
60 * @return a composed {@link FailableIntUnaryOperator} like {@link IntUnaryOperator#andThen(IntUnaryOperator)}.
61 * @throws NullPointerException if after is null.
62 * @see #compose(FailableIntUnaryOperator)
63 */
64 default FailableIntUnaryOperator<E> andThen(final FailableIntUnaryOperator<E> after) {
65 Objects.requireNonNull(after);
66 return (final int t) -> after.applyAsInt(applyAsInt(t));
67 }
68
69 /**
70 * Applies this operator to the given operand.
71 *
72 * @param operand the operand
73 * @return the operator result
74 * @throws E Thrown when a consumer fails.
75 */
76 int applyAsInt(int operand) throws E;
77
78 /**
79 * Returns a composed {@link FailableIntUnaryOperator} like {@link IntUnaryOperator#compose(IntUnaryOperator)}.
80 *
81 * @param before the operator to apply before this one.
82 * @return a composed {@link FailableIntUnaryOperator} like {@link IntUnaryOperator#compose(IntUnaryOperator)}.
83 * @throws NullPointerException if before is null.
84 * @see #andThen(FailableIntUnaryOperator)
85 */
86 default FailableIntUnaryOperator<E> compose(final FailableIntUnaryOperator<E> before) {
87 Objects.requireNonNull(before);
88 return (final int v) -> applyAsInt(before.applyAsInt(v));
89 }
90 }