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.functor.core.composite;
18
19 import java.io.Serializable;
20
21 import org.apache.commons.functor.Function;
22 import org.apache.commons.functor.Procedure;
23 import org.apache.commons.functor.UnaryProcedure;
24
25 /**
26 * A Procedure composed of a Function whose result is then run through a UnaryProcedure.
27 * @version $Revision: 1171154 $ $Date: 2011-09-15 17:58:38 +0200 (Thu, 15 Sep 2011) $
28 * @author Matt Benson
29 */
30 public class TransformedProcedure implements Procedure, Serializable {
31 /**
32 * serialVersionUID declaration.
33 */
34 private static final long serialVersionUID = -4111958123789033410L;
35
36 /** Base hash integer used to shift hash */
37 private static final int HASH_SHIFT = 2;
38
39 /**
40 * Type-remembering helper
41 * @param <X>
42 */
43 private static final class Helper<X> implements Procedure, Serializable {
44 /**
45 * serialVersionUID declaration.
46 */
47 private static final long serialVersionUID = -4093503167446891318L;
48 private Function<? extends X> function;
49 private UnaryProcedure<? super X> procedure;
50
51 /**
52 * Create a new Helper.
53 * @param function Function
54 * @param procedure UnaryFunction
55 */
56 private Helper(Function<? extends X> function, UnaryProcedure<? super X> procedure) {
57 this.function = function;
58 this.procedure = procedure;
59 }
60
61 /**
62 * {@inheritDoc}
63 */
64 public void run() {
65 procedure.run(function.evaluate());
66 }
67 }
68
69 private final Helper<?> helper;
70
71 /**
72 * Create a new TransformedProcedure.
73 * @param <X>
74 * @param function Function
75 * @param procedure UnaryProcedure
76 */
77 public <X> TransformedProcedure(Function<? extends X> function, UnaryProcedure<? super X> procedure) {
78 this.helper = new Helper<X>(function, procedure);
79 }
80
81 /**
82 * {@inheritDoc}
83 */
84 public final void run() {
85 helper.run();
86 }
87
88 /**
89 * {@inheritDoc}
90 */
91 @Override
92 public final boolean equals(Object obj) {
93 return obj == this || obj instanceof TransformedProcedure
94 && equals((TransformedProcedure) obj);
95 }
96
97 /**
98 * Learn whether another TransformedProcedure is equal to <code>this</code>.
99 * @param that instance to test
100 * @return whether equal
101 */
102 public final boolean equals(TransformedProcedure that) {
103 return that != null && that.helper.function.equals(this.helper.function)
104 && that.helper.procedure.equals(this.helper.procedure);
105 }
106
107 /**
108 * {@inheritDoc}
109 */
110 @Override
111 public int hashCode() {
112 int result = "TransformedProcedure".hashCode();
113 result <<= HASH_SHIFT;
114 result |= helper.procedure.hashCode();
115 result <<= HASH_SHIFT;
116 result |= helper.function.hashCode();
117 return result;
118 }
119
120 /**
121 * {@inheritDoc}
122 */
123 @Override
124 public String toString() {
125 return "TransformedProcedure<" + helper.function + "; " + helper.procedure + ">";
126 }
127 }