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
  30                 return true;
  31         }
  32
  33         public abstract ResultSet selectColumnsFromWhere(Column[] columns, Table[] tables, String where);
  34
  35         protected String typeName(Type type) {
  36                 return type.toString();
  37         }
  38
  39         protected String createColumnSql(Column column)
  40         {
  41                 String result = column.getName() + " " + typeName(column.getType());
  42                 if (column.getWidth() > 0) {
  43                         result += "(" + column.getWidth() + ")";
  44                 }
  45
  46                 if (NOT_NULL == column.getNull()) {
  47                         result += " NOT NULL";
  48                 }
  49                 else {
  50                         result += " NULL";
  51                 }
  52
  53                 return result;
  54         }
  55
  56         protected String createTableSql(Table table)
  57         {
  58                 assert(null != table);
  59                 assert(null != table.getName());
  60                 assert(table.getNumColumns() > 0);
  61
  62                 StringBuilder sb = new StringBuilder();
  63
  64                 sb.append("CREATE TABLE ")
  65                   .append(table.getName())
  66                   .append("(");
  67
  68                 for (int idx = 0; idx < table.getNumColumns(); ++idx) {
  69                         if (idx > 0) {
  70                                 sb.append(", ");
  71                         }
  72                         sb.append(createColumnSql(table.getColumn(idx)));
  73                 }
  74
  75                 sb.append(")");
  76
  77                 return sb.toString();
  78         }
  79 }