// Updated version for 2011
 
 /*************************************************************************
  *  Compilation:  javac StdIn.java
  *  Execution:    java StdIn
  *
  *  Reads in data of various types from standard input.
  *
  *************************************************************************/
 
 import java.util.Scanner;
 import java.util.Locale;
 import java.io.BufferedInputStream;
 import java.io.FileInputStream;
 import java.io.InputStream;
 
 /**
  *  <i>Standard input</i>. This class provides methods for reading strings
  *  and numbers from standard input.
  *  <p>
  *  The Locale used is: language = English, country = US. This is consistent
  *  with the formatting conventions with Java floating-point literals,
  *  command-line arguments (via <tt>Double.parseDouble()</tt>)
  *  and standard output (via <tt>System.out.print()</tt>). It ensures that
  *  standard input works with the input files used in the textbook.
  *  <p>
  *  For additional documentation, see <a href="http://www.cs.princeton.edu/introcs/15inout">Section 1.5</a> of
  *  <i>Introduction to Programming in Java: An Interdisciplinary Approach</i> by Robert Sedgewick and Kevin Wayne. 
  *
  * Modified to allow input from a file -- Dan Powell 2011   
  */
 public final class StdIn {
 
 	// Added by DP. Maintains state of where input is coming from
 	private static boolean readingFromFile = false;
 	private static boolean assumeReadingFromFile = false;
 	
 	// assume Unicode UTF-8 encoding
     private static String charsetName = "UTF-8";
 
     // assume language = English, country = US for consistency with System.out.
     private static Locale usLocale = new Locale("en", "US");
 
     // the scanner object
     private static Scanner scanner = new Scanner(new BufferedInputStream(System.in), charsetName);
 
     // static initializer
     static { scanner.useLocale(usLocale); }
 
     // singleton pattern - can't instantiate
     private StdIn() { }
 
 
     /**
      * Is there only whitespace left on standard input?
      */
     public static boolean isEmpty() {
          return !scanner.hasNext();
     }
 
     /**
      * Return next string from standard input
      */
     public static String readString() {
         return scanner.next();
     }
 
     /**
      * Return next int from standard input
      */
     public static int readInt() {
         return scanner.nextInt();
     }
 
     /**
      * Return next double from standard input
      */
     public static double readDouble() {
         return scanner.nextDouble();
     }
 
     /**
      * Return next float from standard input
      */
     public static float readFloat() {
          return scanner.nextFloat();
     }
 
     /**
      * Return next short from standard input
      */
     public static short readShort() {
          return scanner.nextShort();
     }
 
     /**
      * Return next long from standard input
      */
     public static long readLong() {
         return scanner.nextLong();
     }
 
     /**
      * Return next byte from standard input
      */
     public static byte readByte() {
         return scanner.nextByte();
     }
 
     /**
      * Return next boolean from standard input, allowing "true" or "1" for true,
      * and "false" or "0" for false
      */
     public static boolean readBoolean() {
         String s = readString();
         if (s.equalsIgnoreCase("true"))  return true;
         if (s.equalsIgnoreCase("false")) return false;
         if (s.equals("1"))               return true;
         if (s.equals("0"))               return false;
         throw new java.util.InputMismatchException();
     }
 
     /**
      * Does standard input have a next line?
      */
     public static boolean hasNextLine() {
         return scanner.hasNextLine();
     }
 
     /**
      * Return rest of line from standard input
      */
     public static String readLine() {
         return scanner.nextLine();
     }
 
     /**
      * Return next char from standard input
      */
     // a complete hack and inefficient - email me if you have a better
     public static char readChar() {
         // (?s) for DOTALL mode so . matches a line termination character
         // 1 says look only one character ahead
         // consider precompiling the pattern
         String s = scanner.findWithinHorizon("(?s).", 1);
         return s.charAt(0);
     }
 
     /**
      * Return rest of input from standard input
      */
     public static String readAll() {
         if (!scanner.hasNextLine()) return null;
 
         // reference: http://weblogs.java.net/blog/pat/archive/2004/10/stupid_scanner_1.html
         return scanner.useDelimiter("\\A").next();
     }
 
     /**
      * Code to allow a junit test to assume that the correct file
      * has been opened
      */
     public static void assumeReadingFromFile(String filename) {
 
         InputStream is = null;
         try {
             is = new FileInputStream(filename);
             assumeReadingFromFile = true;
         } catch (java.io.FileNotFoundException e) {
             throw new FileNotFoundException("File Not Found: " + filename);
         }
 
         System.setIn(is);
         scanner = new Scanner(new BufferedInputStream(System.in), charsetName);
 
     }
     
     /**
      * Added code for reading from a file -- Dan Powell
      */
     public static void redirectInput(String filename) {
 
         if (assumeReadingFromFile) {
         	readingFromFile = true;
         	return; 
         }
     	
     	InputStream is = null;
         try {
             is = new FileInputStream(filename);
             readingFromFile = true;
         } catch (java.io.FileNotFoundException e) {
             throw new FileNotFoundException("File Not Found: " + filename);
         }
 
         System.setIn(is);
         scanner = new Scanner(new BufferedInputStream(System.in), charsetName);
 
     }
     
     public static boolean isReadingFromFile() {
     	return readingFromFile;
     }
     
     public static class FileNotFoundException extends RuntimeException {
 
 		private static final long serialVersionUID = 1L;
 		
 		public FileNotFoundException(String s) {
 			super(s);
 		}
 		
 		public FileNotFoundException() {
 			super();
 		}
     	
     }
 
 
     /**
      * Unit test
      */
     public static void main(String[] args) {
 
         System.out.println("Type a string: ");
         String s = StdIn.readString();
         System.out.println("Your string was: " + s);
         System.out.println();
 
         System.out.println("Type an int: ");
         int a = StdIn.readInt();
         System.out.println("Your int was: " + a);
         System.out.println();
 
         System.out.println("Type a boolean: ");
         boolean b = StdIn.readBoolean();
         System.out.println("Your boolean was: " + b);
         System.out.println();
 
         System.out.println("Type a double: ");
         double c = StdIn.readDouble();
         System.out.println("Your double was: " + c);
         System.out.println();
 
     }
 
 }