// File: FormatWriter.java from the package edu.colorado.io // Complete documentation is available from the FormatWriter link in: // http://www.cs.colorado.edu/~main/docs package edu.colorado.io; import java.text.NumberFormat; /****************************************************************************** * The FormatWriter class has a collection of static methods for * writing formatted output to System.out. * *

Java Source Code for this class:

* * http://www.cs.colorado.edu/~main/edu/colorado/io/FormatWriter.java * * * @author * Michael Main (main@colorado.edu) with help from Judy Abbott. * * @version * Jan 22, 1999 * * @see EasyReader ******************************************************************************/ public class FormatWriter { // Note: getNumberInstance( ) creates a NumberFormat object using local // information about the characters for a decimal point and separators. private static NumberFormat form = NumberFormat.getNumberInstance( ); /** * Make the computation pause for a specified number of milliseconds. * @param milliseconds * the number of milliseconds to pause *

Postcondition:

* The computation has paused for the specified time. **/ public static void pause(long milliseconds) { try { Thread.sleep(milliseconds); } catch (InterruptedException e) { // Resume execution } } /** * Print a number to System.out, using a specified format. * @param d * the number to be printed * @param minimumWidth * the minimum number of characters in the entire output * @param fractionDigits * the number of digits to print on the right side of the decimal point *

Precondition:

* fractionDigits is not negative. *

Postcondition:

* The number d has been printed to System.out. * This printed number is rounded to the specified number of digits on the * right of the decimal. If fractionDigits is 0, then only the * integer part of d is printed. If necessary, spaces appear * at the front of the number to raise the total number of printed * characters to the minimum. Additional formatting details are obtained * from the current locale. For example, in the United States, a period is * used for the decimal and commas are used to separate groups of * integer digits. * @exception IllegalArgumentException * Indicates that fractionDigits is negative. *

Example:

printNumber(12345.27, 8, 1);
   *   

   *   Prints 12,345.3 in the U.S.
   **/
   public static void printNumber(double d, int minimumWidth, int fractionDigits)
   {
      String output;
      int i;

      // Set the number of digits to appear on the right of the decimal.
      if (fractionDigits < 0)
         throw new IllegalArgumentException("fractionDigits < 0:" + fractionDigits);
      form.setMinimumFractionDigits(fractionDigits);
      form.setMaximumFractionDigits(fractionDigits);
        
      // Round and format the number.
      output = form.format(d);
            
      printRight(output, minimumWidth);
   }


   /**
   * Print an Object (such as a String) to 
   * System.out, using left justification.
   * @param output
   *   the Object to be printed
   * @param minimumWidth
   *   the minimum number of characters in the entire output
   *

Postcondition:


   *   The Object has been printed to System.out.
   *   If necessary, spaces appear
   *   at the front of the Object to raise the total number of printed
   *   characters to the minimum.
   *

Example:


   *   printNumber("Foo", 8);
   *   

   *   Prints "Foo     " (with 5 spaces).
   **/
   public static void printLeft(Object output, int minimumWidth)
   {
      int i;
      String s = output.toString( );
         
      // Print any trailing spaces and the Object itself.
      System.out.print(s);   
      for (i = s.length( ); i < minimumWidth; i++)
         System.out.print(' ');

   }
     
        
   
   /**                    
   * Print an Object (such as a String) to 
   * System.out, using right justification.
   * @param output
   *   the Object to be printed
   * @param minimumWidth
   *   the minimum number of characters in the entire output
   *

Postcondition:


   *   The Object has been printed to System.out.
   *   If necessary, spaces appear
   *   at the front of the Object to raise the total number of printed
   *   characters to the minimum.
   *

Example:


   *   printNumber("Foo", 8);
   *   

   *   Prints "     Foo" (with 5 spaces).
   **/
   public static void printRight(Object output, int minimumWidth)
   {
      int i;
      String s = output.toString( );
            
      // Print any leading spaces and the Object itself.
      for (i = s.length( ); i < minimumWidth; i++)
         System.out.print(' ');
      System.out.print(s);
   }
     
     
   /**
   * Print a whole number to System.out, using a specified format.
   * @param d
   *   the number to be printed
   * @param minimumWidth
   *   the minimum number of characters in the entire output
   *

Postcondition:


   *   The number n has been printed to System.out.
   *   If necessary, spaces appear
   *   at the front of the number to raise the total number of printed
   *   characters to the minimum. Additional formatting details are obtained
   *   from the current locale. For example, in the United States
   *   commas are used to separate groups of
   *   integer digits.
   *

Example:


   *   printNumber(12345, 8);
   *   

   *   Prints "  12,345" in the U.S. (with 2 spaces in front)
   **/
   public static void printWhole(long n, int minimumWidth)
   {
      String output;
        
      // Format the number.
      output = form.format(n);
            
      // Print any leading spaces and the number itself.
      printRight(output, minimumWidth);
   }
   
   
   /**
   * A demonstration program.
   * To run the demonstration: 
   * 
java edu.colorado.io.FormatWriter
   **/
   public static void main(String[ ] args)
   { 
      System.out.println("Each example has output between the square brackets.");
      System.out.println( );
            
      System.out.print("Output of printNumber(12345.27, 8, 1) is: [");
      printNumber(12345.27, 8, 1);
      System.out.println(']');
      
      System.out.print("Output of printNumber(12345.22, 8, 1) is: [");
      printNumber(12345.22, 8, 1);
      System.out.println(']');
      
      System.out.print("Output of printNumber(-2345.27, 8, 1) is: [");
      printNumber(-2345.27, 8, 1);
      System.out.println(']');
      
      System.out.print("Output of printNumber(-2345.22, 8, 1) is: [");
      printNumber(-2345.22, 8, 1);
      System.out.println(']');
      
      System.out.print("Output of printNumber(-2345.22, 8, 0) is: [");
      printNumber(-2345.22, 8, 0);
      System.out.println(']');
      
      System.out.print("Output of printLeft(\"Foo\", 8) is:         [");
      printLeft("Foo", 8);
      System.out.println(']');

      System.out.print("Output of printRight(\"Foo\", 8) is:        [");
      printRight("Foo", 8);
      System.out.println(']');

      System.out.print("Output of printWhole(12345, 8) is:        [");
      printWhole(12345, 8);
      System.out.println(']');
   }
   
    
}