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1 package com.quadcap.sql;
2
3
40
41 import java.io.BufferedOutputStream  ;
42 import java.io.Externalizable ;
43 import java.io.IOException ;
44 import java.io.ObjectInput ;
45 import java.io.ObjectOutput ;
46 import java.io.OutputStream ;
47
48 import java.util.Enumeration ;
49 import java.util.Vector ;
50
51 import java.sql.SQLException ;
52
53 import com.quadcap.sql.io.ObjectInputStream;
54 import com.quadcap.sql.io.ObjectOutputStream;
55 import com.quadcap.sql.io.Extern;
56
57 import com.quadcap.sql.file.BlockAccess;
58 import com.quadcap.sql.file.BlockFile;
59 import com.quadcap.sql.file.PageManager;
60 import com.quadcap.sql.file.SubPageManager;
61
62 import com.quadcap.sql.types.Value;
63
64 import com.quadcap.util.Debug;
65
66
71 public class DropTable extends LogStep implements Externalizable {
72 Relation table;
73 Vector bases;
74
75 public DropTable() {}
76
77 public DropTable(Session session, Relation table) {
78 super(session);
79 this.table = table;
80 }
81
82 public void undo(Session session) throws IOException , SQLException {
83 Database db = session.getDatabase();
84 db.addRelation(table);
85 if (bases != null) {
86 for (int i = 0; i < bases.size(); i++) {
87 db.addViewDependency(bases.elementAt(i).toString(),
88 table.getName());
89 }
90 }
91 }
92
93 public void redo(Session session) throws IOException , SQLException {
94 Database db = session.getDatabase();
95 db.removeRelation(table.getName());
96 }
97
98 public void prepare(Session session) throws IOException , SQLException {
99 Database db = session.getDatabase();
100 Enumeration b = db.getBases(table.getName());
101 this.bases = new Vector ();
102 while (b.hasMoreElements()) {
103 bases.addElement(b.nextElement());
104 }
105 }
106
107 public void readExternal(ObjectInput in)
108 throws IOException , ClassNotFoundException
109 {
110 super.readExternal(in);
111 table = (Relation)in.readObject();
112 this.bases = (Vector )in.readObject();
113 }
114
115 public void writeExternal(ObjectOutput out) throws IOException {
116 super.writeExternal(out);
117 out.writeObject(table);
118 out.writeObject(bases);
119 }
120
121 public String toString() {
123 StringBuffer sb = new StringBuffer (super.toString());
124 sb.append(" DropTable(");
125 sb.append(table.toString());
126 sb.append(')');
127 return sb.toString();
128 }
129
131 static Extern extern;
132 public void setExtern(Extern extern) { DropTable.extern = extern; }
133 public Extern getExtern() { return extern; }
134 }
135 |
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