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.adapter;
18
19 import java.io.Serializable;
20
21 import org.apache.commons.functor.BinaryFunction;
22 import org.apache.commons.functor.BinaryProcedure;
23
24 /**
25 * Adapts a {@link BinaryFunction BinaryFunction}
26 * to the {@link BinaryProcedure BinaryProcedure}
27 * interface by ignoring the value returned
28 * by the function.
29 * <p/>
30 * Note that although this class implements
31 * {@link Serializable}, a given instance will
32 * only be truly <code>Serializable</code> if the
33 * underlying function is. Attempts to serialize
34 * an instance whose delegate is not
35 * <code>Serializable</code> will result in an exception.
36 *
37 * @param <L> the left argument type.
38 * @param <R> the right argument type.
39 * @version $Revision: 1156760 $ $Date: 2011-08-11 21:34:07 +0200 (Thu, 11 Aug 2011) $
40 * @author Rodney Waldhoff
41 */
42 public final class BinaryFunctionBinaryProcedure<L, R> implements BinaryProcedure<L, R>, Serializable {
43
44 /**
45 * serialVersionUID declaration.
46 */
47 private static final long serialVersionUID = 4498276997127058865L;
48 /** The {@link BinaryFunction BinaryFunction} I'm wrapping. */
49 private final BinaryFunction<? super L, ? super R, ?> function;
50
51 /**
52 * Create an {@link BinaryProcedure BinaryProcedure} wrapping
53 * the given {@link BinaryFunction BinaryFunction}.
54 * @param function the {@link BinaryFunction BinaryFunction} to wrap
55 */
56 public BinaryFunctionBinaryProcedure(BinaryFunction<? super L, ? super R, ?> function) {
57 this.function = function;
58 }
59
60 /**
61 * {@link BinaryFunction#evaluate Evaluate} my function, but
62 * ignore its returned value.
63 * {@inheritDoc}
64 */
65 public void run(L left, R right) {
66 function.evaluate(left, right);
67 }
68
69 /**
70 * {@inheritDoc}
71 */
72 public boolean equals(Object that) {
73 return that == this
74 || (that instanceof BinaryFunctionBinaryProcedure<?, ?>
75 && equals((BinaryFunctionBinaryProcedure<?, ?>) that));
76 }
77
78 /**
79 * Learn whether a given BinaryFunctionBinaryPredicate is equal to this.
80 * @param that BinaryFunctionBinaryPredicate to compare
81 * @return boolean
82 */
83 public boolean equals(BinaryFunctionBinaryProcedure<?, ?> that) {
84 return null != that && (null == function ? null == that.function : function.equals(that.function));
85 }
86
87 /**
88 * {@inheritDoc}
89 */
90 public int hashCode() {
91 int hash = "BinaryFunctionBinaryProcedure".hashCode();
92 if (null != function) {
93 hash ^= function.hashCode();
94 }
95 return hash;
96 }
97
98 /**
99 * {@inheritDoc}
100 */
101 public String toString() {
102 return "BinaryFunctionBinaryProcedure<" + function + ">";
103 }
104
105 /**
106 * Adapt the given, possibly-<code>null</code>,
107 * {@link BinaryFunction BinaryFunction} to the
108 * {@link BinaryProcedure BinaryProcedure} interface.
109 * When the given <code>BinaryFunction</code> is <code>null</code>,
110 * returns <code>null</code>.
111 *
112 * @param <L> left type
113 * @param <R> right type
114 * @param function the possibly-<code>null</code>
115 * {@link BinaryFunction BinaryFunction} to adapt
116 * @return a <code>BinaryFunctionBinaryProcedure</code> wrapping the given
117 * {@link BinaryFunction BinaryFunction}, or <code>null</code>
118 * if the given <code>BinaryFunction</code> is <code>null</code>
119 */
120 public static <L, R> BinaryFunctionBinaryProcedure<L, R> adapt(BinaryFunction<? super L, ? super R, ?> function) {
121 return null == function ? null : new BinaryFunctionBinaryProcedure<L, R>(function);
122 }
123
124 }