001 /*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 * http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017 package org.apache.commons.functor.adapter;
018
019 import java.io.Serializable;
020
021 import org.apache.commons.functor.UnaryFunction;
022 import org.apache.commons.functor.UnaryProcedure;
023
024 /**
025 * Adapts a {@link UnaryFunction UnaryFunction}
026 * to the {@link UnaryProcedure UnaryProcedure}
027 * interface by ignoring the value returned
028 * by the function.
029 * <p/>
030 * Note that although this class implements
031 * {@link Serializable}, a given instance will
032 * only be truly <code>Serializable</code> if the
033 * underlying function is. Attempts to serialize
034 * an instance whose delegate is not
035 * <code>Serializable</code> will result in an exception.
036 *
037 * @param <A> the argument type.
038 * @version $Revision: 1157651 $ $Date: 2011-08-14 22:24:05 +0200 (Sun, 14 Aug 2011) $
039 * @author Rodney Waldhoff
040 */
041 public final class UnaryFunctionUnaryProcedure<A> implements UnaryProcedure<A>, Serializable {
042
043 /**
044 * serialVersionUID declaration.
045 */
046 private static final long serialVersionUID = -3578673875995684811L;
047 /** The {@link UnaryFunction UnaryFunction} I'm wrapping. */
048 private final UnaryFunction<? super A, ?> function;
049
050 /**
051 * Create an {@link UnaryProcedure UnaryProcedure} wrapping
052 * the given {@link UnaryFunction UnaryFunction}.
053 * @param function the {@link UnaryFunction UnaryFunction} to wrap
054 */
055 public UnaryFunctionUnaryProcedure(UnaryFunction<? super A, ?> function) {
056 if (function == null) {
057 throw new IllegalArgumentException("UnaryFunction argument was null");
058 }
059 this.function = function;
060 }
061
062 /**
063 * {@link UnaryFunction#evaluate Evaluate} my function, but
064 * ignore its returned value.
065 * {@inheritDoc}
066 */
067 public void run(A obj) {
068 function.evaluate(obj);
069 }
070
071 /**
072 * {@inheritDoc}
073 */
074 public boolean equals(Object that) {
075 return that == this
076 || (that instanceof UnaryFunctionUnaryProcedure<?> && equals((UnaryFunctionUnaryProcedure<?>) that));
077 }
078
079 /**
080 * Learn whether a specified UnaryFunctionUnaryPredicate is equal to this.
081 * @param that the UnaryFunctionUnaryPredicate to test
082 * @return boolean
083 */
084 public boolean equals(UnaryFunctionUnaryProcedure<?> that) {
085 return null != that && (null == function ? null == that.function : function.equals(that.function));
086 }
087
088 /**
089 * {@inheritDoc}
090 */
091 public int hashCode() {
092 int hash = "UnaryFunctionUnaryProcedure".hashCode();
093 if (null != function) {
094 hash ^= function.hashCode();
095 }
096 return hash;
097 }
098
099 /**
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 }