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.BinaryFunction;
022 import org.apache.commons.functor.BinaryProcedure;
023
024 /**
025 * Adapts a {@link BinaryFunction BinaryFunction}
026 * to the {@link BinaryProcedure BinaryProcedure}
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 <L> the left argument type.
038 * @param <R> the right argument type.
039 * @version $Revision: 1156760 $ $Date: 2011-08-11 21:34:07 +0200 (Thu, 11 Aug 2011) $
040 * @author Rodney Waldhoff
041 */
042 public final class BinaryFunctionBinaryProcedure<L, R> implements BinaryProcedure<L, R>, Serializable {
043
044 /**
045 * serialVersionUID declaration.
046 */
047 private static final long serialVersionUID = 4498276997127058865L;
048 /** The {@link BinaryFunction BinaryFunction} I'm wrapping. */
049 private final BinaryFunction<? super L, ? super R, ?> function;
050
051 /**
052 * Create an {@link BinaryProcedure BinaryProcedure} wrapping
053 * the given {@link BinaryFunction BinaryFunction}.
054 * @param function the {@link BinaryFunction BinaryFunction} to wrap
055 */
056 public BinaryFunctionBinaryProcedure(BinaryFunction<? super L, ? super R, ?> function) {
057 this.function = function;
058 }
059
060 /**
061 * {@link BinaryFunction#evaluate Evaluate} my function, but
062 * ignore its returned value.
063 * {@inheritDoc}
064 */
065 public void run(L left, R right) {
066 function.evaluate(left, right);
067 }
068
069 /**
070 * {@inheritDoc}
071 */
072 public boolean equals(Object that) {
073 return that == this
074 || (that instanceof BinaryFunctionBinaryProcedure<?, ?>
075 && equals((BinaryFunctionBinaryProcedure<?, ?>) that));
076 }
077
078 /**
079 * Learn whether a given BinaryFunctionBinaryPredicate is equal to this.
080 * @param that BinaryFunctionBinaryPredicate to compare
081 * @return boolean
082 */
083 public boolean equals(BinaryFunctionBinaryProcedure<?, ?> that) {
084 return null != that && (null == function ? null == that.function : function.equals(that.function));
085 }
086
087 /**
088 * {@inheritDoc}
089 */
090 public int hashCode() {
091 int hash = "BinaryFunctionBinaryProcedure".hashCode();
092 if (null != function) {
093 hash ^= function.hashCode();
094 }
095 return hash;
096 }
097
098 /**
099 * {@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 }