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.Function;
22 import org.apache.commons.functor.Procedure;
23 import org.apache.commons.lang3.Validate;
24
25 /**
26 * Adapts a {@link Function Function}
27 * to the {@link Procedure Procedure}
28 * interface by ignoring the value returned
29 * by the function.
30 * <p/>
31 * Note that although this class implements
32 * {@link Serializable}, a given instance will
33 * only be truly <code>Serializable</code> if the
34 * underlying function is. Attempts to serialize
35 * an instance whose delegate is not
36 * <code>Serializable</code> will result in an exception.
37 *
38 * @version $Revision: 1365377 $ $Date: 2012-07-24 21:59:23 -0300 (Tue, 24 Jul 2012) $
39 */
40 public final class FunctionProcedure implements Procedure, Serializable {
41 /**
42 * serialVersionUID declaration.
43 */
44 private static final long serialVersionUID = -7300031015086684901L;
45 /** The {@link Function Function} I'm wrapping. */
46 private final Function<?> function;
47
48 /**
49 * Create an {@link Procedure Procedure} wrapping
50 * the given {@link Function Function}.
51 * @param function the {@link Function Function} to wrap
52 */
53 public FunctionProcedure(Function<?> function) {
54 this.function = Validate.notNull(function, "Function argument was null");
55 }
56
57 /**
58 * {@inheritDoc}
59 * {@link Function#evaluate Evaluate} my function,
60 * but ignore its returned value.
61 */
62 public void run() {
63 function.evaluate();
64 }
65
66 /**
67 * {@inheritDoc}
68 */
69 @Override
70 public boolean equals(Object that) {
71 return that == this || (that instanceof FunctionProcedure && equals((FunctionProcedure) that));
72 }
73
74 /**
75 * Learn whether another FunctionProcedure is equal to this.
76 * @param that FunctionProcedure to test
77 * @return boolean
78 */
79 public boolean equals(FunctionProcedure that) {
80 return null != that && function.equals(that.function);
81 }
82
83 /**
84 * {@inheritDoc}
85 */
86 @Override
87 public int hashCode() {
88 int hash = "FunctionProcedure".hashCode();
89 hash ^= function.hashCode();
90 return hash;
91 }
92
93 /**
94 * {@inheritDoc}
95 */
96 @Override
97 public String toString() {
98 return "FunctionProcedure<" + function + ">";
99 }
100
101 /**
102 * Adapt the given, possibly-<code>null</code>,
103 * {@link Function Function} to the
104 * {@link Procedure Procedure} interface.
105 * When the given <code>Function</code> is <code>null</code>,
106 * returns <code>null</code>.
107 *
108 * @param function the possibly-<code>null</code>
109 * {@link Function Function} to adapt
110 * @return a {@link Procedure Procedure} wrapping the given
111 * {@link Function Function}, or <code>null</code>
112 * if the given <code>Function</code> is <code>null</code>
113 */
114 public static FunctionProcedure adapt(Function<?> function) {
115 return null == function ? null : new FunctionProcedure(function);
116 }
117
118 }