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


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 import java.io.OutputStream JavaDoc;
46
47 import java.sql.SQLException JavaDoc;
48
49 import com.quadcap.util.Debug;
50 import com.quadcap.sql.io.Extern;
51
52 /**
53  * Log step to add a table to a database.
54  *
55  * @author Stan Bailes
56  */
57 public class AddTable extends LogStep implements Externalizable JavaDoc {
58     Relation table;
59
60     /**
61      * Default constructor
62      */
63     public AddTable() {}
64
65     /**
66      * Explicit constructor from table
67      */
68     public AddTable(Session session, Relation table) {
69         super(session);
70     this.table = table;
71     }
72
73     /**
74      * LogStep.redo(): Add the table to the database
75      */
76     public void redo(Session session) throws IOException JavaDoc, SQLException JavaDoc {
77     Database db = session.getDatabase();
78     db.addRelation(table);
79     }
80
81     /**
82      * LogStep.undo(): Remove the table from the database
83      */
84     public void undo(Session session) throws IOException JavaDoc, SQLException JavaDoc {
85     Database db = session.getDatabase();
86     db.removeRelation(table.getName());
87     }
88
89     /**
90      * LogStep.prepare(): We check for already-existing table and throw
91      * exception early, rather than let the user proceed under false
92      * illusions.
93      */
94     public void prepare(Session session) throws IOException JavaDoc, SQLException JavaDoc {
95     Database db = session.getDatabase();
96         if (db.getRelation(table.getName()) != null) {
97             throw new SQLException JavaDoc("Table/view already exists: " +
98                                    table.getName(),
99                                    "42000");
100         }
101     }
102
103     /**
104      * Read me from a stream
105      */
106     public void readExternal(ObjectInput JavaDoc in)
107     throws IOException JavaDoc, ClassNotFoundException JavaDoc
108     {
109     super.readExternal(in);
110     table = (Relation)in.readObject();
111     }
112
113     /**
114      * Write me to a stream
115      */
116     public void writeExternal(ObjectOutput JavaDoc out) throws IOException JavaDoc {
117     super.writeExternal(out);
118     out.writeObject(table);
119     }
120
121     //#ifdef DEBUG
122 /**
123      * Return a displayable representation for debugging
124      */
125     public String JavaDoc toString() {
126     StringBuffer JavaDoc sb = new StringBuffer JavaDoc(super.toString());
127     sb.append(" AddTable(");
128     sb.append(table.toString());
129     sb.append(')');
130     return sb.toString();
131     }
132     //#endif
133
134     static Extern extern;
135     public void setExtern(Extern extern) { AddTable.extern = extern; }
136     public Extern getExtern() { return extern; }
137 }
138
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