import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.net.MalformedURLException;
import java.util.StringTokenizer;
import java.util.Scanner;

/** Here is a simple Web robot that allows the user to lookup a share price.
 *  Let's assume the stock symbol is given as a command-line argument.
 */
public class Driver
{
  public static void main(String [] args)
    throws MalformedURLException, IOException, InterruptedException
  {
    if (args.length == 0)
    {
      System.out.printf("Usage:  java Driver <stock symbol>\n");
      System.exit(1);
    }

    String symbol = args[0];
    String urlString = "http://finance.yahoo.com/q?s=" + symbol;
    URL url = new URL (urlString);
    InputStream urlIn = url.openStream();
    Scanner in = new Scanner(urlIn);
    String line = "";

    // Look for the line from the Web page that says "Last Trade:"
    boolean foundData = false;
    while(in.hasNextLine())
    {
      line = in.nextLine();

      if (line.indexOf("Last Trade:") >= 0)
      {
        foundData = true;
        break;
      }
    }

    // If we've gone thru the whole Web page and found no trade data, exit.
    if (! foundData)
    {
      System.out.printf("I couldn't find %s's trade data, sorry.", symbol);
      System.exit(1);
    }

    // Okay, it's a very long line, but shortly after the string "Last Trade"
    // we should see the share price, as in this example:
    //          8%">Last Trade:</td><td class="yfnc_tabledata1"><big>
    //          <b><span id="yfs_l10_ibm">107.99<
    int position = line.indexOf("Last Trade:");
    line = line.substring(position, position + 100);

    // Now that we have an extract of the Web page containing the desired
    // price:
    // Set up a StringTokenizer to token out the '<' and '>' symbols, and
    // look for the token that has a '.' in it.
    StringTokenizer tok = new StringTokenizer(line, "<>");

    while(tok.hasMoreTokens())
    {
      String token = tok.nextToken();
      if(token.contains("."))
      {
        double latestPrice = Double.parseDouble(token);
        System.out.printf("The latest share price is $ %.2f\n", latestPrice);
        break;
      }
    }
  }
}