Java Reference
In-Depth Information
L
ISTING
22.7
Continued
request.setAttribute(“price”, rs.getString(“price”));
request.setAttribute(“bid”, rs.getString(“bid”));
request.setAttribute(“ask”, rs.getString(“ask”));
}
}
}
finally {
// release the database connection back into the pool
pool.releaseConnection(con);
22
}
}
}
The
Buy
Service
The
Buy
class is also an implementation of the
Service
interface. Its
execute()
method starts
its execution when a user selects the Buy radio button and fills in symbol and price informa-
tion from the
tradeform.jsp
page. It then gets the symbol and price from the request and per-
forms a
select
statement on the
stocks
table, returning a
ResultSet
containing the stock's
attributes. It then checks for an existing ask price that is either less than or equal to the submit-
ted bid price. If there is a satisfying ask price, the current price is set to the bid price and the
ask price is reset to 0. Otherwise the new bid is updated. The source for the Buy service is in
Listing 22.8.
L
ISTING
22.8
Buy.java
import java.sql.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.ServletContext;
import Service;
import ConnectionPool.ConnectionPool;
public class Buy implements Service {
public Buy() {
}
