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.collections4;
18
19 /**
20 * Defines a functor interface implemented by classes that do something.
21 * <p>
22 * A {@code Closure} represents a block of code which is executed from
23 * inside some block, function or iteration. It operates an input object.
24 * </p>
25 * <p>
26 * Standard implementations of common closures are provided by
27 * {@link ClosureUtils}. These include method invocation and for/while loops.
28 * </p>
29 *
30 * @param <T> the type that the closure acts on
31 * @since 1.0
32 */
33 @FunctionalInterface
34 public interface Closure<T> {
35
36 /**
37 * Performs an action on the specified input object.
38 *
39 * @param input the input to execute on
40 * @throws ClassCastException (runtime) if the input is the wrong class
41 * @throws IllegalArgumentException (runtime) if the input is invalid
42 * @throws FunctorException (runtime) if any other error occurs
43 */
44 void execute(T input);
45
46 }