/*

 * StringGrabber.java 

 *

 * Example code.  Use it as you will.

 *

 */


import java.io.*;

import java.net.*;



public class StringGrabber {


	public static void main(String[] args)

	{
	//do nothing - avoids compile error
	}



	//====================================================================

	// In order to call this method from ASP we must make it public

	//====================================================================

	public String GetString(String urlString, String preString, String postString)

	{

		// Get the web page from the url defined by urlString

		String webPageHTML;

		String DesiredString;

		try {

			webPageHTML = GetWebPageFromUrl(urlString);

			DesiredString = GetStringFromHTML(webPageHTML, preString, postString);

		}

		catch (GetStringException e)

		{

			return "GetString exception: " + e.getMessage();

		}

		catch (Exception e1)

		{

			// Catch any other exception that might occur

			return "Other exception: " + e1.getMessage();

		}

		

		return DesiredString;

	}

	

	//====================================================================

	// Worker methods -- these can be private since we're not 

	// calling them from ASP

	//====================================================================

	
	//====================================================================

	// GetWebPageFromUrl()

	//====================================================================

	private String GetWebPageFromUrl(String urlString) throws GetStringException

	{

		// Create a URL object from urlString

		URL PageURL;

		try {

			PageURL = new URL(urlString);

		}

		catch (MalformedURLException e)

		{

			String msg = "Invalid url: " + urlString;

			throw new GetStringException(msg);

		}

		

		// Open a connection to the URL

		URLConnection PageConnection;

		try {

			PageConnection = PageURL.openConnection();

		}

		catch (IOException e)

		{

			String msg = "Can't open connection to " + urlString;

			throw new GetStringException(msg);

		}

		

		// Get the InputStream from the URL connection

		InputStream webPageInputStream;

		try {

			webPageInputStream = PageConnection.getInputStream();

		}

		catch (IOException e)

		{

			// Could be any server error, but the most likely is 404

			String msg = "404 File Not Found: " + urlString;

			throw new GetStringException(msg);

		}

		

		// Read the web page via the InputStream

		StringBuffer webPageData = new StringBuffer(32000);	

		int totalBytesRead = 0;

		boolean moreToRead = true;

		byte[] readBuf = new byte[4096]; // Read the web page in 4K chunks

		

		while (moreToRead)

		{

			int numBytesRead = 0;

			try {

				numBytesRead = webPageInputStream.read(readBuf);

			}

			catch (IOException e)

			{

				moreToRead = false;

				numBytesRead = -1;

			}

						

			if (numBytesRead > 0)

			{

				totalBytesRead += numBytesRead;

				webPageData.append(new String(readBuf, 0, numBytesRead));

			}

			else

				moreToRead = false;

		}

	

		try {

			webPageInputStream.close();

		}

		catch (IOException e)

		{

			// Ignore any exception that might occur

		}



		webPageData.setLength(totalBytesRead);

			

		return webPageData.toString();

	}

	

	//====================================================================

	// GetStringFromHTML()

	//====================================================================

	private String GetStringFromHTML(String webPageHTML, String preString, String postString) throws GetStringException

	{

		// Look for the preString

		int preStringLoc = webPageHTML.indexOf(preString);

		if (preStringLoc == -1)

		{

			String msg = "Couldn't find the preString " + preString;

			throw new GetStringException(msg);

		}



		// Found the preString, so look for the postString

		int postStringLoc = webPageHTML.indexOf(postString, preStringLoc);

		if (postStringLoc == -1)

		{

			String msg = "Couldn't find the postString " + postString;

			throw new GetStringException(msg);

		}

		

		// The stock price is between the preString and postString

		String DesiredString = webPageHTML.substring(preStringLoc + preString.length(), postStringLoc);

		return DesiredString;

	}

}



//====================================================================

// 

//  class GetStringException

// 

//  Convenience class to make it easy to return errors from our

//  worker methods.  This let's us separate StockGrabber errors

//  from coding errors (what, coding errors?!).

//

//====================================================================





class GetStringException extends Exception

{

	public GetStringException (String msg)

    {

		super(msg);

    }

}