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comparison src/nabble/model/DbUpdater.java @ 0:7ecd1a4ef557

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author Franklin Schmidt <fschmidt@gmail.com>
date Thu, 21 Mar 2019 19:15:52 -0600
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-1:000000000000 0:7ecd1a4ef557
1 package nabble.model;
2
3 import java.sql.Connection;
4 import java.sql.Statement;
5 import java.sql.ResultSet;
6 import java.sql.SQLException;
7 import java.util.Map;
8 import org.slf4j.Logger;
9 import org.slf4j.LoggerFactory;
10 import fschmidt.db.DbDatabase;
11
12
13 final class DbUpdater {
14 private static final Logger logger = LoggerFactory.getLogger(DbUpdater.class);
15
16 final DbDatabase db;
17 final String schema;
18 private int dbVersion;
19 Connection con;
20 Statement stmt;
21
22 DbUpdater(DbDatabase db,String schema) {
23 this.db = db;
24 this.schema = schema;
25 dbVersion = databaseVersion();
26 }
27
28 int databaseVersion() {
29 return databaseVersion(db,schema);
30 }
31
32 static int databaseVersion(DbDatabase db,String schema) {
33 try {
34 Connection con = db.getConnection();
35 try {
36 Statement stmt = con.createStatement();
37 ResultSet rs = stmt.executeQuery(
38 "select version from "+schema+".version"
39 );
40 rs.next();
41 int dbVersion = rs.getInt("version");
42 stmt.close();
43 return dbVersion;
44 } finally {
45 con.close();
46 }
47 } catch(SQLException e) {
48 throw new RuntimeException(e);
49 }
50 }
51
52 int dbVersion() {
53 return dbVersion;
54 }
55
56 void begin()
57 throws SQLException
58 {
59 con = db.getConnection();
60 con.setAutoCommit(false);
61 stmt = con.createStatement(ResultSet.TYPE_FORWARD_ONLY,ResultSet.CONCUR_UPDATABLE);
62 logger.error(schema+" step "+dbVersion);
63 }
64
65 void commit()
66 throws SQLException
67 {
68 stmt.executeUpdate(
69 "update "+schema+".version set version=" + (++dbVersion)
70 );
71 stmt.close();
72 con.commit();
73 con.close();
74 con = null;
75 }
76
77 void exec(String sql)
78 throws SQLException
79 {
80 if( sql != null ) {
81 if( sql.trim().toLowerCase().startsWith("select ") ) {
82 stmt.executeQuery(sql);
83 } else {
84 stmt.executeUpdate(sql);
85 }
86 }
87 }
88
89 void execStep(String sql)
90 throws SQLException
91 {
92 begin();
93 exec(sql);
94 commit();
95 }
96
97 void close() {
98 if( con != null ) {
99 try {
100 con.close();
101 } catch(SQLException e) {
102 logger.error(schema,e);
103 }
104 con = null;
105 }
106 }
107
108 }