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package example.corba;
import java.sql.*;
/**
* This class handles the JDBC side of things. It opens a connection to
* the database, and performes queries on that database.
*
* In essence, you could use this class on it's own. The rest of the classes
* in this example handle either the CORBA mechanism, or the frontend.
*
* Note: Before you ask, why perform a query on each call, you have to remember
* that an object could be changed by another client, and we need to ensure that
* the returned data is live and accurate.
*
* $Id: StockDB.java,v 1.1 1999/01/25 21:22:03 scrappy Exp $
*/
public class StockDB
{
Connection con;
Statement st;
// the current stock number
int id = -1;
public void connect(String url,String usr,String pwd) throws Exception {
Class.forName("postgresql.Driver");
System.out.println("Connecting to "+url);
con = DriverManager.getConnection(url,usr,pwd);
st = con.createStatement();
}
public void closeConnection() throws Exception {
con.close();
}
public void fetchItem(int id) throws Exception {
this.id = id;
}
public int newItem() throws Exception {
// tba
return -1;
}
public String getDescription() throws SQLException {
ResultSet rs = st.executeQuery("select description from stock where id="+id);
if(rs!=null) {
rs.next();
String s = rs.getString(1);
rs.close();
return s;
}
throw new SQLException("No ResultSet");
}
public int getAvailable() throws SQLException {
ResultSet rs = st.executeQuery("select avail from stock where id="+id);
if(rs!=null) {
rs.next();
int v = rs.getInt(1);
rs.close();
return v;
}
throw new SQLException("No ResultSet");
}
public int getOrdered() throws SQLException {
ResultSet rs = st.executeQuery("select ordered from stock where id="+id);
if(rs!=null) {
rs.next();
int v = rs.getInt(1);
rs.close();
return v;
}
throw new SQLException("No ResultSet");
}
public boolean isItemValid() throws SQLException {
ResultSet rs = st.executeQuery("select valid from stock where id="+id);
if(rs!=null) {
rs.next();
boolean b = rs.getBoolean(1);
rs.close();
return b;
}
throw new SQLException("No ResultSet");
}
public void addNewStock(int amount) throws SQLException {
st.executeUpdate("update stock set avail=avail+"+amount+
", ordered=ordered-"+amount+
" where id="+id+" and ordered>="+amount);
}
public void removeStock(int amount) throws SQLException {
st.executeUpdate("update stock set avail=avail-"+amount+
" where id="+id);
}
public void orderStock(int amount) throws SQLException {
st.executeUpdate("update stock set ordered=ordered+"+amount+
" where id="+id);
}
public int getLastID() throws SQLException {
ResultSet rs = st.executeQuery("select max(id) from stock");
if(rs!=null) {
rs.next();
int v = rs.getInt(1);
rs.close();
return v;
}
throw new SQLException("No ResultSet");
}
}
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