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Java > Open Source Codes > org > hsqldb > SequenceManager


1 /* Copyright (c) 2001-2005, The HSQL Development Group
2  * All rights reserved.
3  *
4  * Redistribution and use in source and binary forms, with or without
5  * modification, are permitted provided that the following conditions are met:
6  *
7  * Redistributions of source code must retain the above copyright notice, this
8  * list of conditions and the following disclaimer.
9  *
10  * Redistributions in binary form must reproduce the above copyright notice,
11  * this list of conditions and the following disclaimer in the documentation
12  * and/or other materials provided with the distribution.
13  *
14  * Neither the name of the HSQL Development Group nor the names of its
15  * contributors may be used to endorse or promote products derived from this
16  * software without specific prior written permission.
17  *
18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
19  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21  * ARE DISCLAIMED. IN NO EVENT SHALL HSQL DEVELOPMENT GROUP, HSQLDB.ORG,
22  * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
23  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
24  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
25  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
26  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
28  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29  */
30
31
32 package org.hsqldb;
33
34 import org.hsqldb.HsqlNameManager.HsqlName;
35 import org.hsqldb.lib.HashMappedList;
36 import org.hsqldb.persist.Logger;
37
38 /**
39  * Manages SEQUENCE objects for a Database instance. <p>
40  *
41  * @author fredt@users
42  * @version 1.7.2
43  * @since 1.7.2
44  */
45 public class SequenceManager {
46
47     HashMappedList sequenceMap;
48
49     SequenceManager() {
50         sequenceMap = new HashMappedList();
51     }
52
53     /**
54      * Drops a sequence with the specified name from this Database
55      *
56      * @param name of the sequence to drop
57      * @throws HsqlException if a database access error occurs
58      */
59     void dropSequence(String JavaDoc name) throws HsqlException {
60
61         boolean found = sequenceMap.containsKey(name);
62
63         Trace.check(found, Trace.SEQUENCE_NOT_FOUND, name);
64         sequenceMap.remove(name);
65     }
66
67     public NumberSequence getSequence(String JavaDoc name) {
68         return (NumberSequence) sequenceMap.get(name);
69     }
70
71     NumberSequence createSequence(HsqlName hsqlname, long start,
72                                   long increment,
73                                   int type) throws HsqlException {
74
75         Trace.check(!sequenceMap.containsKey(hsqlname.name),
76                     Trace.SEQUENCE_ALREADY_EXISTS);
77
78         NumberSequence sequence = new NumberSequence(hsqlname, start,
79             increment, type);
80
81         sequenceMap.put(hsqlname.name, sequence);
82
83         return sequence;
84     }
85
86     String JavaDoc logSequences(Session c, Logger logger) throws HsqlException {
87
88         for (int i = 0; i < sequenceMap.size(); i++) {
89             NumberSequence seq = (NumberSequence) sequenceMap.get(i);
90
91             if (seq.wasUsed()) {
92                 logger.writeSequenceStatement(c, seq);
93                 seq.resetWasUsed();
94             }
95         }
96
97         return null;
98     }
99 }
100
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