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.core.composite;
018
019 import java.io.Serializable;
020 import java.util.ArrayList;
021 import java.util.Iterator;
022 import java.util.List;
023
024 import org.apache.commons.functor.UnaryProcedure;
025
026 /**
027 * A {@link UnaryProcedure UnaryProcedure}
028 * that {@link UnaryProcedure#run runs} an ordered
029 * sequence of {@link UnaryProcedure UnaryProcedures}.
030 * When the sequence is empty, this procedure is does
031 * nothing.
032 * <p>
033 * Note that although this class implements
034 * {@link Serializable}, a given instance will
035 * only be truly <code>Serializable</code> if all the
036 * underlying functors are. Attempts to serialize
037 * an instance whose delegates are not all
038 * <code>Serializable</code> will result in an exception.
039 * </p>
040 * @version $Revision: 1156320 $ $Date: 2011-08-10 21:14:50 +0200 (Wed, 10 Aug 2011) $
041 * @author Rodney Waldhoff
042 */
043 public class UnarySequence<A> implements UnaryProcedure<A>, Serializable {
044
045 /**
046 * serialVersionUID declaration.
047 */
048 private static final long serialVersionUID = 9194268249717820246L;
049 // attributes
050 // ------------------------------------------------------------------------
051 private List<UnaryProcedure<? super A>> list = new ArrayList<UnaryProcedure<? super A>>();
052
053 // constructor
054 // ------------------------------------------------------------------------
055 /**
056 * Create a new UnarySequence.
057 */
058 public UnarySequence() {
059 super();
060 }
061
062 /**
063 * Create a new UnarySequence instance.
064 *
065 * @param procedures to run sequentially
066 */
067 public UnarySequence(UnaryProcedure<? super A>... procedures) {
068 this();
069 if (procedures != null) {
070 for (UnaryProcedure<? super A> p : procedures) {
071 then(p);
072 }
073 }
074 }
075
076 /**
077 * Create a new UnarySequence instance.
078 *
079 * @param procedures to run sequentially
080 */
081 public UnarySequence(Iterable<UnaryProcedure<? super A>> procedures) {
082 this();
083 if (procedures != null) {
084 for (UnaryProcedure<? super A> p : procedures) {
085 then(p);
086 }
087 }
088 }
089
090 // modifiers
091 // ------------------------------------------------------------------------
092 /**
093 * Fluently add a UnaryProcedure to the sequence.
094 * @param p UnaryProcedure to add
095 * @return this
096 */
097 public UnarySequence<A> then(UnaryProcedure<? super A> p) {
098 list.add(p);
099 return this;
100 }
101
102 // predicate interface
103 // ------------------------------------------------------------------------
104 /**
105 * {@inheritDoc}
106 */
107 public void run(A obj) {
108 for (Iterator<UnaryProcedure<? super A>> iter = list.iterator(); iter.hasNext();) {
109 iter.next().run(obj);
110 }
111 }
112
113 /**
114 * {@inheritDoc}
115 */
116 public boolean equals(Object that) {
117 return that == this || (that instanceof UnarySequence<?> && equals((UnarySequence<?>) that));
118 }
119
120 /**
121 * Learn whether another UnarySequence is equal to this.
122 * @param that UnarySequence to test
123 * @return boolean
124 */
125 public boolean equals(UnarySequence<?> that) {
126 // by construction, list is never null
127 return null != that && list.equals(that.list);
128 }
129
130 /**
131 * {@inheritDoc}
132 */
133 public int hashCode() {
134 // by construction, list is never null
135 return "UnarySequence".hashCode() ^ list.hashCode();
136 }
137
138 /**
139 * {@inheritDoc}
140 */
141 public String toString() {
142 return "UnarySequence<" + list + ">";
143 }
144
145 }