Skeleton Program

The program must work correctly with an empty file. This may seem dumb, but there is no reason to have a program break when it is used in an unexpected fashion. Here is the copy program with pieces left out:

class CopyMaker
{
  String sourceName, destName;
  BufferedReader source;
  PrintWriter dest;
  String line;

  CopyMaker ( String source, String dest )
  {
    sourceName = source;
    destName   = dest;
  }
  
  private boolean openFiles()  // return true if files open, else false
  {
  }

  private void copyFiles()
  {
  }

  private void closeFiles() 
  {
  }

  public static void main ( String[] args ) 
  {
    if ( args.length == 3 && args[1].toUpperCase().equals("TO") )
    {
      CopyMaker cp = new CopyMaker( args[0], args[2] );
      if ( cp.openFiles() )
      {
        cp.copyFiles() ; 
        cp.closeFiles() ;
       }
    }
    else
      System.out.println("java CopyTextFile source to destination");
  }

}

Rather than write one big main() it is convenient to define an object whose several methods implement the steps in copying files. Potentially the object could be used as a component of a larger program.

The main() method collects information from the user. If the information looks correct, it creates a CopyMaker object and calls its methods.