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.UnaryFunction;
22 import org.apache.commons.functor.UnaryProcedure;
23
24 /**
25 * Adapts a {@link UnaryFunction UnaryFunction}
26 * to the {@link UnaryProcedure UnaryProcedure}
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 <A> the argument type.
38 * @version $Revision: 1157651 $ $Date: 2011-08-14 22:24:05 +0200 (Sun, 14 Aug 2011) $
39 * @author Rodney Waldhoff
40 */
41 public final class UnaryFunctionUnaryProcedure<A> implements UnaryProcedure<A>, Serializable {
42
43 /**
44 * serialVersionUID declaration.
45 */
46 private static final long serialVersionUID = -3578673875995684811L;
47 /** The {@link UnaryFunction UnaryFunction} I'm wrapping. */
48 private final UnaryFunction<? super A, ?> function;
49
50 /**
51 * Create an {@link UnaryProcedure UnaryProcedure} wrapping
52 * the given {@link UnaryFunction UnaryFunction}.
53 * @param function the {@link UnaryFunction UnaryFunction} to wrap
54 */
55 public UnaryFunctionUnaryProcedure(UnaryFunction<? super A, ?> function) {
56 if (function == null) {
57 throw new IllegalArgumentException("UnaryFunction argument was null");
58 }
59 this.function = function;
60 }
61
62 /**
63 * {@link UnaryFunction#evaluate Evaluate} my function, but
64 * ignore its returned value.
65 * {@inheritDoc}
66 */
67 public void run(A obj) {
68 function.evaluate(obj);
69 }
70
71 /**
72 * {@inheritDoc}
73 */
74 public boolean equals(Object that) {
75 return that == this
76 || (that instanceof UnaryFunctionUnaryProcedure<?> && equals((UnaryFunctionUnaryProcedure<?>) that));
77 }
78
79 /**
80 * Learn whether a specified UnaryFunctionUnaryPredicate is equal to this.
81 * @param that the UnaryFunctionUnaryPredicate to test
82 * @return boolean
83 */
84 public boolean equals(UnaryFunctionUnaryProcedure<?> that) {
85 return null != that && (null == function ? null == that.function : function.equals(that.function));
86 }
87
88 /**
89 * {@inheritDoc}
90 */
91 public int hashCode() {
92 int hash = "UnaryFunctionUnaryProcedure".hashCode();
93 if (null != function) {
94 hash ^= function.hashCode();
95 }
96 return hash;
97 }
98
99 /**
100 * {@inheritDoc}
101 */
102 public String toString() {
103 return "UnaryFunctionUnaryProcedure<" + function + ">";
104 }
105
106 /**
107 * Adapt the given, possibly-<code>null</code>,
108 * {@link UnaryFunction UnaryFunction} to the
109 * {@link UnaryProcedure UnaryProcedure} interface.
110 * When the given <code>UnaryFunction</code> is <code>null</code>,
111 * returns <code>null</code>.
112 *
113 * @param <A> the argument type.
114 * @param function the possibly-<code>null</code>
115 * {@link UnaryFunction UnaryFunction} to adapt
116 * @return a {@link UnaryProcedure UnaryProcedure} wrapping the given
117 * {@link UnaryFunction UnaryFunction}, or <code>null</code>
118 * if the given <code>UnaryFunction</code> is <code>null</code>
119 */
120 public static <A> UnaryFunctionUnaryProcedure<A> adapt(UnaryFunction<? super A, ?> function) {
121 return null == function ? null : new UnaryFunctionUnaryProcedure<A>(function);
122 }
123
124 }