KickJava   Java API By Example, From Geeks To Geeks.

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


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.ByteArrayOutputStream JavaDoc;
42 import java.io.Externalizable JavaDoc;
43 import java.io.IOException JavaDoc;
44 import java.io.ObjectInput JavaDoc;
45 import java.io.ObjectOutput JavaDoc;
46
47 import java.util.Vector JavaDoc;
48
49 import java.sql.ResultSet JavaDoc;
50 import java.sql.SQLException JavaDoc;
51
52 import com.quadcap.sql.index.Btree;
53
54 import com.quadcap.sql.file.BlockFile;
55 import com.quadcap.sql.file.ByteUtil;
56
57 import com.quadcap.util.Debug;
58
59 /**
60  * If a table has no other constraints (e.g., primary key, unique), we
61  * synthesize this constraint to force the creation of an index, since
62  * the table traversal code depends on having an index to iterate.
63  * This is a performance hit for full table scans.
64  *
65  * @author Stan Bailes
66  */
67 public class DefaultTableConstraint extends IndexConstraint
68                                     implements Externalizable JavaDoc
69 {
70     /**
71      * Default constructor
72      */
73     public DefaultTableConstraint() {
74         this.useComparator = false;
75     }
76
77     /**
78      * Externalizable.readExternal(): Read me from a stream.
79      */
80     public void readExternal(ObjectInput JavaDoc in)
81     throws IOException JavaDoc, ClassNotFoundException JavaDoc
82     {
83     super.readExternal(in);
84     }
85     
86     /**
87      * Externalizable.writeExternal(): Write me to a stream.
88      */
89     public void writeExternal(ObjectOutput JavaDoc out) throws IOException JavaDoc {
90     super.writeExternal(out);
91     }
92
93     /**
94      * IndexConstraint.makeKey(): My key is simply the rowId, which is
95      * a short 8-byte quantity guaranteed to be unique. So there.
96      */
97     public byte[] makeKey(Session session, Row row, long rowId) {
98         byte[] key = new byte[8];
99         ByteUtil.putLong(key, 0, rowId);
100         return key;
101     }
102
103     //#ifdef DEBUG
104 /**
105      * Return a string representation for debugging
106      */
107     public String JavaDoc toString() {
108     return getName();
109     }
110     //#endif
111
112     public String JavaDoc constraintType() { return "default table constraint"; }
113 }
114
Popular Tags