Reading Data from a File

This chapter discusses Java's FileReader and BufferedReader classes in detail. FileReader and BufferedReader classes are used together when reading data from an external file. The use of the BufferedReader class allows data to be buffered as it is read from a file before manipulating it. The readLine() method of the BufferedReader class reads a line of text from a character-oriented input stream, and puts it into a new String object.

9. Skeleton Program



Answer:
Yes.






Skeleton Program



    
        

        

        

            
                
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");
  }

}

            		
        

    


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:
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.







Question 9:
If the files open successfully but there is a problem in making the copy, should the program close the files?