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Java > Open Source Codes > smallsql > database > StorePage


1 /* =============================================================
2  * SmallSQL : a free Java DBMS library for the Java(tm) platform
3  * =============================================================
4  *
5  * (C) Copyright 2004-2006, by Volker Berlin.
6  *
7  * Project Info: http://www.smallsql.de/
8  *
9  * This library is free software; you can redistribute it and/or modify it
10  * under the terms of the GNU Lesser General Public License as published by
11  * the Free Software Foundation; either version 2.1 of the License, or
12  * (at your option) any later version.
13  *
14  * This library is distributed in the hope that it will be useful, but
15  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
16  * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
17  * License for more details.
18  *
19  * You should have received a copy of the GNU Lesser General Public
20  * License along with this library; if not, write to the Free Software
21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
22  * USA.
23  *
24  * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
25  * in the United States and other countries.]
26  *
27  * ---------------
28  * StorePage.java
29  * ---------------
30  * Author: Volker Berlin
31  *
32  * Created on 28.08.2004
33  */

34 package smallsql.database;
35
36 import java.io.*;
37 import java.sql.SQLException JavaDoc;
38
39 /**
40  * @author Volker Berlin
41  */

42 class StorePage {
43     byte[] page; // Daten einer Page
44
int pageSize;
45     RandomAccessFile raFile;
46     long fileOffset; // Position in Datei
47

48     StorePage(byte[] page, int pageSize, RandomAccessFile raFile, long fileOffset){
49         this.page = page;
50         this.pageSize = pageSize;
51         this.raFile = raFile;
52         this.fileOffset = fileOffset;
53     }
54     
55     
56     final void setPageData(byte[] data, int size){
57         page = data;
58         pageSize = size;
59     }
60
61
62     long commit() throws SQLException JavaDoc{
63         try{
64             if(raFile != null){
65                 // if new page then append at end of file
66
if(fileOffset < 0){
67                     fileOffset = raFile.length();
68                 }
69                 raFile.seek(fileOffset);
70                 raFile.write(page, 0, pageSize);
71                 //raFile.getFD().sync();
72
}
73             return fileOffset;
74         }catch(Exception JavaDoc e){
75             throw Utils.createSQLException(e);
76         }
77     }
78
79     
80     final void rollback(){
81         raFile = null;
82     }
83     
84     void freeLock(){}
85 }
86
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