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.BinaryProcedure;
022 import org.apache.commons.functor.UnaryProcedure;
023
024 /**
025 * Adapts a
026 * {@link BinaryProcedure BinaryProcedure}
027 * to the
028 * {@link UnaryProcedure UnaryProcedure} interface
029 * using a constant left-side argument.
030 * <p/>
031 * Note that although this class implements
032 * {@link Serializable}, a given instance will
033 * only be truly <code>Serializable</code> if the
034 * underlying objects are. Attempts to serialize
035 * an instance whose delegates are not
036 * <code>Serializable</code> will result in an exception.
037 *
038 * @param <A> the argument type.
039 * @version $Revision: 1157644 $ $Date: 2011-08-14 22:19:52 +0200 (Sun, 14 Aug 2011) $
040 * @author Rodney Waldhoff
041 */
042 public final class RightBoundProcedure<A> implements UnaryProcedure<A>, Serializable {
043 /**
044 * serialVersionUID declaration.
045 */
046 private static final long serialVersionUID = 3267188080481758226L;
047 /** The {@link BinaryProcedure BinaryProcedure} I'm wrapping. */
048 private final BinaryProcedure<? super A, Object> procedure;
049 /** The parameter to pass to {@code procedure}. */
050 private final Object param;
051
052 /**
053 * Create a new RightBoundProcedure.
054 * @param <R> bound arg type
055 * @param procedure the procedure to adapt
056 * @param arg the constant argument to use
057 */
058 @SuppressWarnings("unchecked")
059 public <R> RightBoundProcedure(BinaryProcedure<? super A, ? super R> procedure, R arg) {
060 if (procedure == null) {
061 throw new IllegalArgumentException("BinaryProcedure argument was null");
062 }
063 this.procedure = (BinaryProcedure<? super A, Object>) procedure;
064 this.param = arg;
065 }
066
067 /**
068 * {@inheritDoc}
069 */
070 public void run(A obj) {
071 procedure.run(obj, param);
072 }
073
074 /**
075 * {@inheritDoc}
076 */
077 public boolean equals(Object that) {
078 return that == this || (that instanceof RightBoundProcedure<?> && equals((RightBoundProcedure<?>) that));
079 }
080
081 /**
082 * Learn whether another RightBoundProcedure is equal to this.
083 * @param that RightBoundProcedure to test
084 * @return boolean
085 */
086 public boolean equals(RightBoundProcedure<?> that) {
087 return null != that
088 && (null == procedure ? null == that.procedure : procedure.equals(that.procedure))
089 && (null == param ? null == that.param : param.equals(that.param));
090 }
091
092 /**
093 * {@inheritDoc}
094 */
095 public int hashCode() {
096 int hash = "RightBoundProcedure".hashCode();
097 if (null != procedure) {
098 hash <<= 2;
099 hash ^= procedure.hashCode();
100 }
101 if (null != param) {
102 hash <<= 2;
103 hash ^= param.hashCode();
104 }
105 return hash;
106 }
107
108 /**
109 * {@inheritDoc}
110 */
111 public String toString() {
112 return "RightBoundProcedure<" + procedure + "(?," + param + ")>";
113 }
114
115 /**
116 * Get a UnaryProcedure from <code>procedure</code>.
117 * @param <L> the left argument type.
118 * @param <R> the right argument type.
119 * @param procedure to adapt
120 * @param arg right side argument
121 * @return RightBoundProcedure
122 */
123 public static <L, R> RightBoundProcedure<L> bind(BinaryProcedure<? super L, ? super R> procedure, R arg) {
124 return null == procedure ? null : new RightBoundProcedure<L>(procedure, arg);
125 }
126
127 }