/**
 *
 *  Copyright (C) 2001  Enterprise Distributed Technologies Ltd
 *
 *  www.enterprisedt.com
 *
 *  This code is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License as published by the Free Software Foundation; either
 *  version 2.1 of the License, or (at your option) any later version.
 *
 *  This library is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 *  Bug fixes, suggestions and comments should be sent to:
 *
 *  bruce@enterprisedt.com
 *
 *  or by snail mail to:
 *
 *  Bruce P. Blackshaw
 *  53 Wakehurst Road
 *  London SW11 6DB
 *  United Kingdom
 *
 *  Change Log:
 *
 *      $Log$
 *
 */

package com.enterprisedt.demo.oracle;

import java.sql.*;
import java.io.*;
import oracle.jdbc.driver.*;

/**
 *  Class demonstrates how an Oracle stored proc that
 *  returns a result set can be called from Java
 *
 *  @author         Bruce Blackshaw
 *  @version        $Revision: 1.2 $
 */
public class JDBCDemo {

    /**
     *  Compile-time flag for deciding which query to use
     */
    private boolean useOracleQuery = true;

    /**
     *  Class name of Oracle JDBC driver
     */
    private String driver = "oracle.jdbc.driver.OracleDriver";

    /**
     *  Initial url fragment
     */
    private String url = "jdbc:oracle:thin:@";


    /**
     *  Standard Oracle listener port
     */
    private String port = "1521";


    /**
     *  Oracle style of calling a stored procedure
     */
    private String oracleQuery = "begin ? := sp_get_stocks(?); end;";


    /**
     *  JDBC style of calling a stored procedure
     */
    private String genericQuery = "{ call ? := sp_get_stocks(?) }";


    /**
     *  Connection to database
     */
    private Connection conn = null;


    /**
     *  Constructor. Loads the JDBC driver and establishes a connection
     *
     *  @param  host        the host the db is on
     *  @param  db          the database name
     *  @param  user        user's name
     *  @param  password    user's password
     */
    public JDBCDemo(String host, String db, String user, String password)
        throws ClassNotFoundException, SQLException {

        // construct the url
        url = url + host + ":" + port + ":" + db;

        // load the Oracle driver and establish a connection
        try {
            Class.forName(driver);
            conn = DriverManager.getConnection(url, user, password);
        }
        catch (ClassNotFoundException ex) {
            System.out.println("Failed to find driver class: " + driver);
            throw ex;
        }
        catch (SQLException ex) {
            System.out.println("Failed to establish a connection to: " + url);
            throw ex;
        }
    }


    /**
     *  Execute the stored procedure
     *
     *  @param   price  price parameter for stored procedure
     */
    private void execute(float price)
        throws SQLException {

        String query = useOracleQuery ? oracleQuery : genericQuery;
        System.out.println("Query: " + query + "\n");
        CallableStatement stmt = conn.prepareCall(query);

        // register the type of the out param - an Oracle specific type
        stmt.registerOutParameter(1, OracleTypes.CURSOR);

        // set the in param
        stmt.setFloat(2, price);

        // execute and retrieve the result set
        stmt.execute();
        ResultSet rs = (ResultSet)stmt.getObject(1);

        // print the results
        while (rs.next()) {
            System.out.println(rs.getString(1) + "\t" +
                               rs.getFloat(2) + "\t" +
                               rs.getDate(3).toString());
        }

        rs.close();
        stmt.close();
    }


    /**
     *  Cleanup the connection
     */
    private void cleanup() throws SQLException {

        if (conn != null)
            conn.close();
    }


    /**
     *  Prints usage statement on stdout
     */
    static private void usage() {

        System.out.println("java com.enterprisedt.demo.oracle.JDBCDemo " +
            " host db user password price");
    }


    /**
     *  Runs the class
     */
    public static void main(String[] args) throws Exception {

        if (args.length != 5) {
            JDBCDemo.usage();
            System.exit(1);
        }
        else {
            try {
                // assign the args to sensible variables for clarity
                String host = args[0];
                String db = args[1];
                String user = args[2];
                String password = args[3];
                float price = Float.valueOf(args[4]).floatValue();

                // and execute the stored proc
                JDBCDemo jdbc = new JDBCDemo(host, db, user, password);
                jdbc.execute(price);
                jdbc.cleanup();
            }
            catch (ClassNotFoundException ex) {
                System.out.println("Demo failed");
            }
            catch (SQLException ex) {
                System.out.println("Demo failed: " + ex.getMessage());
            }
        }
    }
}