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.functors;
18
19 import java.io.Serializable;
20 import java.util.Collection;
21 import java.util.Objects;
22
23 import org.apache.commons.collections4.Closure;
24
25 /**
26 * Closure implementation that chains the specified closures together.
27 *
28 * @since 3.0
29 */
30 public class ChainedClosure<E> implements Closure<E>, Serializable {
31
32 /** Serial version UID */
33 private static final long serialVersionUID = -3520677225766901240L;
34
35 /**
36 * Factory method that performs validation and copies the parameter array.
37 *
38 * @param <E> the type that the closure acts on
39 * @param closures the closures to chain, copied, no nulls
40 * @return the {@code chained} closure
41 * @throws NullPointerException if the closures array is null
42 * @throws NullPointerException if any closure in the array is null
43 */
44 public static <E> Closure<E> chainedClosure(final Closure<? super E>... closures) {
45 FunctorUtils.validate(closures);
46 if (closures.length == 0) {
47 return NOPClosure.<E>nopClosure();
48 }
49 return new ChainedClosure<>(closures);
50 }
51
52 /**
53 * Create a new Closure that calls each closure in turn, passing the
54 * result into the next closure. The ordering is that of the iterator()
55 * method on the collection.
56 *
57 * @param <E> the type that the closure acts on
58 * @param closures a collection of closures to chain
59 * @return the {@code chained} closure
60 * @throws NullPointerException if the closures collection is null
61 * @throws NullPointerException if any closure in the collection is null
62 */
63 @SuppressWarnings("unchecked")
64 public static <E> Closure<E> chainedClosure(final Collection<? extends Closure<? super E>> closures) {
65 Objects.requireNonNull(closures, "closures");
66 if (closures.isEmpty()) {
67 return NOPClosure.<E>nopClosure();
68 }
69 // convert to array like this to guarantee iterator() ordering
70 final Closure<? super E>[] cmds = new Closure[closures.size()];
71 int i = 0;
72 for (final Closure<? super E> closure : closures) {
73 cmds[i++] = closure;
74 }
75 FunctorUtils.validate(cmds);
76 return new ChainedClosure<>(false, cmds);
77 }
78
79 /** The closures to call in turn */
80 private final Closure<? super E>[] iClosures;
81
82 /**
83 * Hidden constructor for the use by the static factory methods.
84 *
85 * @param clone if {@code true} the input argument will be cloned
86 * @param closures the closures to chain, no nulls
87 */
88 private ChainedClosure(final boolean clone, final Closure<? super E>... closures) {
89 iClosures = clone ? FunctorUtils.copy(closures) : closures;
90 }
91
92 /**
93 * Constructor that performs no validation.
94 * Use {@code chainedClosure} if you want that.
95 *
96 * @param closures the closures to chain, copied, no nulls
97 */
98 public ChainedClosure(final Closure<? super E>... closures) {
99 this(true, closures);
100 }
101
102 /**
103 * Execute a list of closures.
104 *
105 * @param input the input object passed to each closure
106 */
107 @Override
108 public void execute(final E input) {
109 for (final Closure<? super E> iClosure : iClosures) {
110 iClosure.execute(input);
111 }
112 }
113
114 /**
115 * Gets the closures.
116 *
117 * @return a copy of the closures
118 * @since 3.1
119 */
120 public Closure<? super E>[] getClosures() {
121 return FunctorUtils.<E>copy(iClosures);
122 }
123
124 }