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.core.composite;
18
19 import java.io.Serializable;
20 import java.util.ArrayList;
21 import java.util.Iterator;
22 import java.util.List;
23
24 import org.apache.commons.functor.BinaryProcedure;
25
26 /**
27 * A {@link BinaryProcedure BinaryProcedure}
28 * that {@link BinaryProcedure#run runs} an ordered
29 * sequence of {@link BinaryProcedure BinaryProcedures}.
30 * When the sequence is empty, this procedure is does
31 * nothing.
32 * <p>
33 * Note that although this class implements
34 * {@link Serializable}, a given instance will
35 * only be truly <code>Serializable</code> if all the
36 * underlying functors are. Attempts to serialize
37 * an instance whose delegates are not all
38 * <code>Serializable</code> will result in an exception.
39 * </p>
40 *
41 * @version $Revision: 1171154 $ $Date: 2011-09-15 17:58:38 +0200 (Thu, 15 Sep 2011) $
42 * @author Rodney Waldhoff
43 */
44 public class BinarySequence<L, R> implements BinaryProcedure<L, R>, Serializable {
45 /**
46 * serialVersionUID declaration.
47 */
48 private static final long serialVersionUID = 1371075584406178258L;
49 // attributes
50 // ------------------------------------------------------------------------
51 private final List<BinaryProcedure<? super L, ? super R>> list =
52 new ArrayList<BinaryProcedure<? super L, ? super R>>();
53
54 // constructor
55 // ------------------------------------------------------------------------
56 /**
57 * Create a new BinarySequence.
58 */
59 public BinarySequence() {
60 super();
61 }
62
63 /**
64 * Create a new BinarySequence instance.
65 *
66 * @param procedures to run sequentially
67 */
68 public BinarySequence(BinaryProcedure<? super L, ? super R>... procedures) {
69 this();
70 if (procedures != null) {
71 for (BinaryProcedure<? super L, ? super R> p : procedures) {
72 then(p);
73 }
74 }
75 }
76
77 /**
78 * Create a new BinarySequence instance.
79 *
80 * @param procedures to run sequentially
81 */
82 public BinarySequence(Iterable<BinaryProcedure<? super L, ? super R>> procedures) {
83 this();
84 if (procedures != null) {
85 for (BinaryProcedure<? super L, ? super R> p : procedures) {
86 then(p);
87 }
88 }
89 }
90
91 /**
92 * Fluently add a BinaryProcedure.
93 * @param p BinaryProcedure to add
94 * @return this
95 */
96 public final BinarySequence<L, R> then(BinaryProcedure<? super L, ? super R> p) {
97 list.add(p);
98 return this;
99 }
100
101 // predicate interface
102 // ------------------------------------------------------------------------
103 /**
104 * {@inheritDoc}
105 */
106 public final void run(L left, R right) {
107 for (Iterator<BinaryProcedure<? super L, ? super R>> iter = list.iterator(); iter.hasNext();) {
108 iter.next().run(left, right);
109 }
110 }
111
112 /**
113 * {@inheritDoc}
114 */
115 public final boolean equals(Object that) {
116 return that == this || (that instanceof BinarySequence<?, ?> && equals((BinarySequence<?, ?>) that));
117 }
118
119 /**
120 * Learn whether another BinarySequence is equal to this.
121 * @param that BinarySequence to test
122 * @return boolean
123 */
124 public final boolean equals(BinarySequence<?, ?> that) {
125 // by construction, list is never null
126 return null != that && list.equals(that.list);
127 }
128
129 /**
130 * {@inheritDoc}
131 */
132 public int hashCode() {
133 // by construction, list is never null
134 return "BinarySequence".hashCode() ^ list.hashCode();
135 }
136
137 /**
138 * {@inheritDoc}
139 */
140 public String toString() {
141 return "BinarySequence<" + list + ">";
142 }
143
144 }