prod/net/jaekl/cfb/db/driver/DbDriver.java

   1 package net.jaekl.cfb.db.driver;
   2
   3 import static net.jaekl.cfb.db.Column.Null.*;
   4
   5 import java.sql.Connection;
   6 import java.sql.PreparedStatement;
   7 import java.sql.ResultSet;
   8 import java.sql.SQLException;
   9
  10 import net.jaekl.cfb.db.Column;
  11 import net.jaekl.cfb.db.Column.Type;
  12 import net.jaekl.cfb.db.Table;
  13
  14 public abstract class DbDriver {
  15         DbDriver() {
  16
  17         }
  18
  19         // Load the JDBC driver
  20         public abstract void load() throws ClassNotFoundException;
  21
  22         public abstract Connection connect(String host, int port, String dbName, String user, String pass) throws SQLException;
  23
  24         public boolean createTable(Connection con, Table table) throws SQLException {
  25                 String sql = createTableSql(table);
  26                 try (PreparedStatement ps = con.prepareStatement(sql)) {
  27                         ps.executeUpdate();
  28                 }
  29                 catch (SQLException exc) {
  30                         throw new SQLException("Failed to executeUpdate:  " + sql, exc);
  31                 }
  32
  33                 return true;
  34         }
  35
  36         public abstract ResultSet selectColumnsFromWhere(Column[] columns, Table[] tables, String where);
  37
  38         protected String typeName(Type type) {
  39                 return type.toString();
  40         }
  41
  42         protected String createColumnSql(Column column)
  43         {
  44                 String result = column.getName() + " " + typeName(column.getType());
  45                 if (column.getWidth() > 0) {
  46                         result += "(" + column.getWidth() + ")";
  47                 }
  48
  49                 if (NOT_NULL == column.getNull()) {
  50                         result += " NOT NULL";
  51                 }
  52                 else {
  53                         result += " NULL";
  54                 }
  55
  56                 return result;
  57         }
  58
  59         protected String createTableSql(Table table)
  60         {
  61                 assert(null != table);
  62                 assert(null != table.getName());
  63                 assert(table.getNumColumns() > 0);
  64
  65                 StringBuilder sb = new StringBuilder();
  66
  67                 sb.append("CREATE TABLE ")
  68                   .append(table.getName())
  69                   .append("(");
  70
  71                 for (int idx = 0; idx < table.getNumColumns(); ++idx) {
  72                         if (idx > 0) {
  73                                 sb.append(", ");
  74                         }
  75                         sb.append(createColumnSql(table.getColumn(idx)));
  76                 }
  77
  78                 sb.append(")");
  79
  80                 return sb.toString();
  81         }
  82 }