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Java > Open Source Codes > com > quadcap > sql > file > NullStore


1 package com.quadcap.sql.file;
2
3 /* Copyright 1997 - 2003 Quadcap Software. All rights reserved.
4  *
5  * This software is distributed under the Quadcap Free Software License.
6  * This software may be used or modified for any purpose, personal or
7  * commercial. Open Source redistributions are permitted. Commercial
8  * redistribution of larger works derived from, or works which bundle
9  * this software requires a "Commercial Redistribution License"; see
10  * http://www.quadcap.com/purchase.
11  *
12  * Redistributions qualify as "Open Source" under one of the following terms:
13  *
14  * Redistributions are made at no charge beyond the reasonable cost of
15  * materials and delivery.
16  *
17  * Redistributions are accompanied by a copy of the Source Code or by an
18  * irrevocable offer to provide a copy of the Source Code for up to three
19  * years at the cost of materials and delivery. Such redistributions
20  * must allow further use, modification, and redistribution of the Source
21  * Code under substantially the same terms as this license.
22  *
23  * Redistributions of source code must retain the copyright notices as they
24  * appear in each source code file, these license terms, and the
25  * disclaimer/limitation of liability set forth as paragraph 6 below.
26  *
27  * Redistributions in binary form must reproduce this Copyright Notice,
28  * these license terms, and the disclaimer/limitation of liability set
29  * forth as paragraph 6 below, in the documentation and/or other materials
30  * provided with the distribution.
31  *
32  * The Software is provided on an "AS IS" basis. No warranty is
33  * provided that the Software is free of defects, or fit for a
34  * particular purpose.
35  *
36  * Limitation of Liability. Quadcap Software shall not be liable
37  * for any damages suffered by the Licensee or any third party resulting
38  * from use of the Software.
39  */
40
41 import java.io.File JavaDoc;
42 import java.io.FileDescriptor JavaDoc;
43 import java.io.IOException JavaDoc;
44 import java.io.RandomAccessFile JavaDoc;
45
46 import java.util.BitSet JavaDoc;
47
48 import com.quadcap.util.collections.LongIterator;
49 import com.quadcap.util.collections.LongMap;
50
51 import com.quadcap.util.Debug;
52 import com.quadcap.util.Util;
53
54 import com.quadcap.sql.Version;
55
56 /**
57  * The null store, which is part of the memory-only implementation.
58  * @author Stan Bailes
59  */
60 public class NullStore extends BlockStore {
61
62     public NullStore() {}
63
64     /**
65      * Initialize a new BlockStore object using the specified file and
66      * blocksize.
67      *
68      * @param file the underlying file.
69      * @param mode "r" for readonly access, otherwise "rw"
70      * @param blocksize the block size to use when creating the file.
71      * @param the synchronization object
72      */
73     public void init(File JavaDoc file, String JavaDoc mode, int blockSize, Object JavaDoc lock)
74         throws IOException JavaDoc
75     {
76     }
77
78     /**
79      * Read a block into a buffer. If the specified block is beyond the
80      * current end of file, then grow the file
81      *
82      * @param blockNum the number of the block to read.
83      * @param buf the buffer into which the data is read.
84      */
85     public void read(long blockNum, byte[] buf, int off)
86     throws IOException JavaDoc
87     {
88         throw new IOException JavaDoc("NullStore.read()");
89     }
90     
91     /**
92      * Write a block from a buffer into the file.
93      *
94      * @param blockNum the number of the block to write.
95      * @param buf the buffer from which the data is written.
96      * @exception IOException if an I/O error occurs.
97      */
98     public void write(long blockNum, byte[] buf)
99     throws IOException JavaDoc
100     {
101         throw new IOException JavaDoc("NullStore.write()");
102     }
103
104     /**
105      * Restore a block image
106      */
107     public void restore(long blockNum, byte[] buf, int off)
108         throws IOException JavaDoc
109     {
110         throw new IOException JavaDoc("NullStore.restore()");
111     }
112
113     public void setLength(long length) throws IOException JavaDoc {
114     }
115
116     public boolean isEncrypted() {
117         return false;
118     }
119     
120     public void close() throws IOException JavaDoc {
121     }
122
123     public void flush() throws IOException JavaDoc {
124     }
125 }
126
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