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Java > Open Source Codes > com > quadcap > sql > DeleteIndexEntry


1 package com.quadcap.sql;
2
3 /* Copyright 1999 - 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.Externalizable JavaDoc;
42 import java.io.IOException JavaDoc;
43 import java.io.ObjectInput JavaDoc;
44 import java.io.ObjectOutput JavaDoc;
45
46 import java.sql.SQLException JavaDoc;
47
48 import com.quadcap.sql.file.BlockFile;
49 import com.quadcap.sql.file.ByteUtil;
50 import com.quadcap.sql.file.SubPageManager;
51 import com.quadcap.sql.io.Extern;
52
53 import com.quadcap.sql.index.Btree;
54
55 import com.quadcap.util.Debug;
56 import com.quadcap.util.Util;
57
58 /**
59  * Log step to delete an index entry.
60  *
61  * @author Stan Bailes
62  */
63 public class DeleteIndexEntry extends ModIndexEntry
64 implements Externalizable JavaDoc {
65     byte[] data;
66
67     /**
68      * Default constructor
69      */
70     public DeleteIndexEntry() {}
71
72     /**
73      * Explicit constructor
74      */
75     public DeleteIndexEntry(Session session, Constraint constraint,
76                             byte[] key) {
77     super(session, constraint, key);
78     }
79
80     public void redo(Session session) throws IOException JavaDoc, SQLException JavaDoc {
81     if (index == null) getIndex(session);
82     index.delete(key);
83     }
84
85     public void undo(Session session) throws IOException JavaDoc {
86         if (data != null) {
87             if (index == null) getIndex(session);
88             long rowId = ByteUtil.getLong(data, 0);
89             ByteUtil.putLong(data, 0, session.getLog().getRowMap(rowId));
90             index.set(key, data);
91         }
92     }
93
94     public void prepare(Session session) throws IOException JavaDoc {
95     if (index == null) getIndex(session);
96     this.data = index.get(key);
97     }
98
99     /**
100      * Read me from a stream
101      *
102      * @exception IOException may be thrown
103      */
104     public void readExternal(ObjectInput JavaDoc in)
105     throws IOException JavaDoc, ClassNotFoundException JavaDoc
106     {
107     super.readExternal(in);
108         this.data = null;
109     int cnt = in.readInt();
110         if (cnt > 0) {
111             data = new byte[cnt];
112             in.read(data);
113         }
114     }
115     
116     /**
117      * Write me to a stream
118      *
119      * @exception IOException may be thrown
120      */
121     public void writeExternal(ObjectOutput JavaDoc out) throws IOException JavaDoc {
122     super.writeExternal(out);
123     if (data == null) {
124         out.writeInt(0);
125     } else {
126         out.writeInt(data.length);
127         out.write(data);
128     }
129     }
130
131     //#ifdef DEBUG
132 /**
133      * Return string representation for debugging
134      */
135     public String JavaDoc toString() {
136     return "Del: " + super.toString() + ", rowId = " +
137             (data != null && data.length >= 8
138              ? SubPageManager.toString(ByteUtil.getLong(data, 0))
139              : "<NULL>");
140     }
141     //#endif
142
143     /**
144      * My class's extern object
145      */
146     static Extern extern;
147     public void setExtern(Extern extern) { DeleteIndexEntry.extern = extern; }
148     public Extern getExtern() { return extern; }
149 }
150
151
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