/*
 * Sample Java program for "DB2 Tutorial: Using DB2 Client on the 
 * TeragGrid Cluster". 
 * A complete tutorial can be found at:
 *			http://www.teragrid.org/userinfo/guide_software.html
 *
 * This sample program shows how to load DB2 Type 2 JDBC driver,
 * connect to a database, and execute a simple query.
 *
 * Last Update: 07/22/04
 * 
 */

import java.sql.*;
import java.lang.*;
import java.io.*;
import COM.ibm.db2.jdbc.app.*; //DB2 UDB JDBC classes. Do not need this if
                              //are using type 4 driver
public class tgsample {
  static
  {
  	try 
	{
	  //Loads Type 2 Driver	
  	  Class.forName("COM.ibm.db2.jdbc.app.DB2Driver");   		  		
	  
	  //For type 4 Driver: Class.forName("com.ibm.db2.jcc.DB2Driver");
	} 
	catch (ClassNotFoundException e)
	{
	   System.err.println("Could not load DB2 driver \n");
	   System.err.println(e.getMessage());
   	   System.exit(1);
	}
  }


  public static void main(String args[]) 
  {
			
	/* Type 4 driver url */
	//String url = "jdbc:db2j:net://machine-name:port-number/TGSAMPLE";

	/* Type 2 driver url */
	String url = "jdbc:db2:tgsample";
	String uname = null, psswrd = null;

	/* Our query from the tutorial */
	String query = "SELECT lastname,salary FROM viswanat.employee WHERE bonus = 500";	

	/* We need username and password before we can connect */
	try
	{
	  BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
	  System.out.print("Enter your username on DataStar: ");
	  uname = br.readLine();

          PasswordField pf = new PasswordField();
	  psswrd = pf.getPassword("Enter your password: ");

	} catch (IOException e) {
	  System.out.print("Failed to get uname/passwd"); 
 	  System.out.println(":" + e.getMessage());
	  System.exit(1);
	}
			
	try
	{
	  //Connect to a database	
	  Connection conn = DriverManager.getConnection(url, uname, psswrd);
	  
	  //Create statement for the connections
	  Statement stmt = conn.createStatement();
	  
	  //Execute the query
	  ResultSet rs = stmt.executeQuery(query);

	  //Loop through the result and print it out
	  System.out.println(query);
	  System.out.println("\nLASTNAME      \tSALARY");
	  System.out.println("----------------------------");
					  
	  while (rs.next())
	  {
	    System.out.print(rs.getString(1) + "     \t" );
		System.out.println(rs.getString(2));
	  }
 		
	  rs.close();
	  stmt.close();
	  conn.close();
	}
	catch (SQLException e) 
	{
	  System.out.println("SQL Exception: ");
	  System.err.println(e.getMessage());
	}
  }//main
} //class


/**
 * This class prompts the user for a password and attempts to mask input with ""
 * This code is taken from: http://java.sun.com/features/2002/09/pword_mask.html
 * Note: you do not need this class in order to connect to a database; 
 * this is here only for your convenience.
 * 
 */

class PasswordField {

  /**
   *@param prompt The prompt to display to the user.
   *@return The password as entered by the user.
   */

   String getPassword(String prompt) throws IOException {
      // password holder
      String password = "";
	  int counter = 0;
      MaskingThread maskingthread = new MaskingThread(prompt);
      Thread thread = new Thread(maskingthread);
      thread.start();
      // block until enter is pressed
      while (true) {
         char c = (char)System.in.read();
         // assume enter pressed, stop masking
		System.out.flush();
         maskingthread.stopMasking();

         if (c == '\r') {
            c = (char)System.in.read();
            if (c == '\n') {
               break;
            } else {
               continue;
            }
         } else if (c == '\n') {
            break;
         } else {
            // store the password
            password += c;
         }
      }
      return password;
   }
}


/**
 * This class attempts to erase characters echoed to the console. It's made to
 *  work with PasswordField class (see above).
 */

class MaskingThread extends Thread {
   private boolean stop = false;
   private int index;
   private String prompt;


  /**
   *@param prompt The prompt displayed to the user
   */
   public MaskingThread(String prompt) {
      this.prompt = prompt;
   }

  /**
   * Begin masking until asked to stop.
   */
   public void run() {
      while(!stop) {
         try {
            // attempt masking at this rate
            this.sleep(1);
         }catch (InterruptedException iex) {
            iex.printStackTrace();
         }
         if (!stop) {
            System.out.print("\r" + prompt +  " \r" + prompt );
         }
         System.out.flush();
      }
   }

  /**
   * Instruct the thread to stop masking.
   */
   public void stopMasking() {
      this.stop = true;
   }
}