1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one
3 * or more contributor license agreements. See the NOTICE file
4 * distributed with this work for additional information
5 * regarding copyright ownership. The ASF licenses this file
6 * to you under the Apache License, Version 2.0 (the
7 * "License"); you may not use this file except in compliance
8 * with the License. You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing,
13 * software distributed under the License is distributed on an
14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15 * KIND, either express or implied. See the License for the
16 * specific language governing permissions and limitations
17 * under the License.
18 *
19 */
20 package org.apache.directory.server.core.avltree;
21
22
23 import org.apache.directory.server.i18n.I18n;
24
25
26 /**
27 * Stores either a single object or many of them in an AvlTree.
28 *
29 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
30 */
31 public class SingletonOrOrderedSet<V>
32 {
33 private V singleton;
34 private AvlTree<V> orderedSet;
35
36
37 /**
38 * Creates a new instance of SingletonOrOrderedSet with a singleton value.
39 *
40 * @param singleton the singleton value
41 */
42 public SingletonOrOrderedSet( V singleton )
43 {
44 if ( singleton == null )
45 {
46 throw new IllegalArgumentException( I18n.err( I18n.ERR_447 ) );
47 }
48
49 this.singleton = singleton;
50 }
51
52
53 /**
54 * Creates a new instance of SingletonOrOrderedSet with a set of ordered
55 * values.
56 *
57 * @param orderedSet the set of ordered values
58 */
59 public SingletonOrOrderedSet( AvlTree<V> orderedSet )
60 {
61 if ( orderedSet == null )
62 {
63 throw new IllegalArgumentException( I18n.err( I18n.ERR_448 ) );
64 }
65
66 this.orderedSet = orderedSet;
67 }
68
69
70 /**
71 * Gets whether or not the stored value is a singleton.
72 *
73 * @return true if in singleton mode, false otherwise
74 */
75 public boolean isSingleton()
76 {
77 return singleton != null;
78 }
79
80
81 /**
82 * Gets whether or not the stored value is an ordered set.
83 *
84 * @return true if in ordered set mode, false otherwise
85 */
86 public boolean isOrderedSet()
87 {
88 return orderedSet != null;
89 }
90
91
92 /**
93 * Gets the singleton value.
94 *
95 * @return the singleton value
96 * @exception RuntimeException if not in singleton mode
97 */
98 public V getSingleton()
99 {
100 if ( singleton != null )
101 {
102 return singleton;
103 }
104
105 throw new RuntimeException( I18n.err( I18n.ERR_449 ) );
106 }
107
108
109 /**
110 * Sets the singleton if in singleton mode.
111 *
112 * @param singleton the singleton value to set
113 * @return old single value
114 */
115 public V setSingleton( V singleton )
116 {
117 if ( singleton == null )
118 {
119 throw new IllegalArgumentException( I18n.err( I18n.ERR_447 ) );
120 }
121
122 if ( this.orderedSet != null )
123 {
124 throw new RuntimeException( I18n.err( I18n.ERR_450 ) );
125 }
126
127 V retval = this.singleton;
128 this.singleton = singleton;
129 return retval;
130 }
131
132
133 /**
134 * Switches from orderedSet mode to singleton mode, while returning the
135 * ordered set of values before removing them forever.
136 *
137 * @param singleton the singleton value
138 * @return the set of ordered values before nulling it out
139 * @exception RuntimeException if already in singleton mode
140 */
141 public AvlTree<V> switchToSingleton( V singleton )
142 {
143 if ( singleton == null )
144 {
145 throw new IllegalArgumentException( I18n.err( I18n.ERR_447 ) );
146 }
147
148 if ( this.singleton != null )
149 {
150 throw new RuntimeException( I18n.err( I18n.ERR_451 ) );
151 }
152
153 AvlTree<V> retval = this.orderedSet;
154 this.orderedSet = null;
155 this.singleton = singleton;
156 return retval;
157 }
158
159
160 /**
161 * Gets the ordered set.
162 *
163 * @return the ordered set
164 * @exception RuntimeException if in singleton mode
165 */
166 public AvlTree<V> getOrderedSet()
167 {
168 if ( orderedSet != null )
169 {
170 return orderedSet;
171 }
172
173 throw new RuntimeException( I18n.err( I18n.ERR_452 ) );
174 }
175
176
177 /**
178 * Sets the set of ordered values.
179 *
180 * @param orderedSet the set of ordered values to use
181 * @return the old set of ordered values
182 * @exception RuntimeException if in singleton mode
183 */
184 public AvlTree<V> setOrderedSet( AvlTree<V> orderedSet )
185 {
186 if ( orderedSet == null )
187 {
188 throw new IllegalArgumentException( I18n.err( I18n.ERR_448 ) );
189 }
190
191 if ( this.singleton != null )
192 {
193 throw new RuntimeException( I18n.err( I18n.ERR_453 ) );
194 }
195
196 AvlTree<V> retval = this.orderedSet;
197 this.orderedSet = orderedSet;
198 return retval;
199 }
200
201
202 /**
203 * Switches from orderedSet mode to singleton mode, while returning the
204 * singleton value before removing it forever.
205 *
206 * @param orderedSet the AvlTree to use for orderedSet of values
207 * @return the singleton to return before nulling it out
208 * @throws RuntimeException if the mode is already in orderedSet mode.
209 */
210 public V switchToOrderedSet( AvlTree<V> orderedSet )
211 {
212 if ( orderedSet == null )
213 {
214 throw new IllegalArgumentException( I18n.err( I18n.ERR_448 ) );
215 }
216
217 if ( this.orderedSet != null )
218 {
219 throw new RuntimeException( I18n.err( I18n.ERR_454 ) );
220 }
221
222 V retval = this.singleton;
223 this.orderedSet = orderedSet;
224 this.singleton = null;
225 return retval;
226 }
227 }