/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

	Copyright (c) John D. Mitchell, 1997 -- All Rights Reserved

PROJECT:	JavaWorld
MODULE:		Tips & Tricks
FILE:		Redirect.java

AUTHOR:		John D. Mitchell, Jun 16, 1997

REVISION HISTORY:
	Name	Date		Description
	----	----		-----------
	JDM	97.06.16   	Initial version.

DESCRIPTION:
	This file highlights the ability to redirect the standard
	input, standard output, and standard error streams using Java
	v1.1.

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/

import	java.io.*;


public class Redirect
{
    public static void main (String args[])
    {
	// Save the current standard input, output, and error streams
	// for later restoration.
	InputStream	origIn	= System.in;
	PrintStream	origOut	= System.out;
	PrintStream	origErr	= System.err;

	// Create a new input stream from a file.
	InputStream	stdin	= null;
	try
	    {
	    stdin = new FileInputStream ("Redirect.in");
	    }
	catch (Exception e)
	    {
	    // Sigh.  Couldn't open the file.
	    System.out.println ("Redirect:  Unable to open input file!");
	    System.exit (1);
	    }

	// Create a new output stream for the standard output.
	PrintStream	stdout	= null;
	try 
	    {
	    stdout = new PrintStream (
		new FileOutputStream ("Redirect.out"));
	    }
	catch (Exception e)
	    {
	    // Sigh.  Couldn't open the file.
	    System.out.println ("Redirect:  Unable to open output file!");
	    System.exit (1);
	    }

	// Create new output stream for the standard error output.
	PrintStream	stderr	= null;
	try
	    {
	    stderr = new PrintStream (
		new FileOutputStream ("Redirect.err"));
	    }
	catch (Exception e)
	    {
	    // Sigh.  Couldn't open the file.
	    System.out.println ("Redirect:  Unable to open error file!");
	    System.exit (1);
	    }

	// Print stuff to the original output and error streams.
	// On most systems all of this will end up on your console when you
	// run this application.
	origOut.println ("\nRedirect:  Round #1");
	System.out.println ("Test output via 'System.out'.");
	origOut.println ("Test output via 'origOut' reference.");
	System.err.println ("Test output via 'System.err'.");
	origErr.println ("Test output via 'origErr' reference.");

	// Set the System out and err streams to use our replacements.
	System.setIn ( stdin );
	System.setOut ( stdout );
	System.setErr ( stderr );

	// Print stuff to the original output and error streams.
	// The stuff printed through the 'origOut' and 'origErr' references
	// should go to the console on most systems while the messages
	// printed through the 'System.out' and 'System.err' will end up in
	// the files we created for them.
	origOut.println ("\nRedirect:  Round #2");
	System.out.println ("Test output via 'System.out'.");
	origOut.println ("Test output via 'origOut' reference.");
	System.err.println ("Test output via 'System.err'.");
	origErr.println ("Test output via 'origErr' reference.");

	// Read some input and dump it to the console.
	origOut.println ("\nRedirect:  Round #3");
	int	inChar	= 0;
	while (-1 != inChar)
	    {
	    try
		{
		inChar = System.in.read();
		}
	    catch (Exception e)
		{
		// Clean up the output and bail.
		origOut.print ("\n");
		break;
		}
	    origOut.write (inChar);
	    }

	// Close the streams.
	try
	    {
	    stdin.close ();
	    stdout.close ();
	    stderr.close ();
	    }
	catch (Exception e)
	    {
	    origOut.println ("Redirect:  Unable to close files!");
	    System.exit (1);
	    }

	System.exit (0);
    }
}