/*
 * $Id: Console.java,v 1.1.1.1 2002/06/05 21:56:32 root Exp $
 *
 * Developed for "Rethinking CS101", a project of Lynn Andrea Stein's AP Group.
 * For more information, see <a href="http://www.ai.mit.edu/projects/cs101/">the
 * CS101 homepage</a> or email <las@ai.mit.edu>.
 *
 * Copyright (C) 1998 Massachusetts Institute of Technology.
 * Please do not redistribute without obtaining permission.
 */
package cs101.io;
import java.io.*;

/**
 * A helper class for Java Console IO.  Contains appropriate console read
 * and print methods.
 *
 * <P>Exists mostly to make System.In palatable by transforming it into a 
 * readLine-able BufferedReader.  Out is included for completeness
 * and uniformity.
 *
 * <P>Copyright 1998 Massachusetts Institute of Technology
 *
 * @see      java.lang.System
 *
 * @author   Lynn Andrea Stein, las@ai.mit.edu
 * @version  $Id: Console.java,v 1.1.1.1 2002/06/05 21:56:32 root Exp $
 * 
 */
public class Console {

  /** A console Reader; e.g., allows you to readLine() from the console. */
  private static final BufferedReader in = 
    new BufferedReader(new InputStreamReader(System.in));
  
  /** A console Writer; e.g., allows you to println() to the console */
  private static final PrintWriter out = 
    new PrintWriter ( System.out , true);
  
  /** The special console Writer for error messages. */
  private static final PrintWriter err = 
    new PrintWriter( System.err , true);
  
  /** Read a line from Console.  The String returned is not terminated
   * with a newline. */  
  public static final String readln() {
    try {
      return Console.in.readLine();
    } catch (java.io.IOException ioe) {
      // Something strange has happened.  Report error and continue.
      Console.err.println("Console.readLine() threw IOException.  Has System.in been redirected?");
      return "";
    }
  }

  /** Write a line to Console.  The String writen is concatenated with a 
   * newline. */
  public static final void println(String s) {
    Console.out.println(s);
  }

  /** Write a blank line to Console. */
  public static final void println() {
    Console.out.println();
  }

  /** Write a line to Console.  The String written is not concatenated with
   * a newline. */
  public static final void print(String s) {
    Console.out.print(s);
    Console.out.flush();
  }

  /**
   * Prevent instantiation
   */
  private Console() {}
}

/* Comments:
 *
 * History:
 *     $Log: Console.java,v $
 *     Revision 1.1.1.1  2002/06/05 21:56:32  root
 *     CS101 comes to Olin finally.
 *
 *     Revision 1.10  1999/07/28 22:22:04  las
 *     Added files providing utility classes for stringTransformer pset
 *     (mostly interfaces concerning connectors).  Also modified Console to
 *     fix a bug in print (i.e., needed to force flush()).
 *
 *     Revision 1.9  1999/01/25 15:30:03  tparnell
 *     fix javadoc to reflect file movement between packages
 *
 *     Revision 1.8  1998/08/11 22:30:54  tparnell
 *     added println() [no args]
 *
 *     Revision 1.7  1998/07/28 18:55:54  tparnell
 *     removed refrences to (now defunct) java.io.FriendlyReader
 *
 *     Revision 1.6  1998/07/24 17:07:29  tparnell
 *     Placate new javadoc behavior
 *
 *     Revision 1.5  1998/07/22 20:24:46  tparnell
 *     made in, out, and err private
 *
 *     Revision 1.4  1998/07/22 15:37:13  tparnell
 *     moved to cs101.io
 *
 *     Revision 1.3  1998/07/21 19:24:54  tparnell
 *     added private Console()
 *
 *     Revision 1.2  1998/07/20 21:57:02  tparnell
 *     Added readLine(), print(), and println()
 *
 *     Revision 1.1  1998/06/08 18:11:52  tparnell
 *     added files from Lynn
 *
 */