/**
 *  <PRE>
 *  FileChanger.java
 *
 *  Revisions: 1.0 Oct. 05, 2002
 *               Created the FileChanger class
 *			   1.1 Oct. 06, 2002
 *				 Compiled, Commented
 *			   2.0 Oct. 06, 2002
 *				 Deleted all, start from scratch, clean up code
 *			   2.1 Oct. 06, 2002
 *				 Completed classes
 *			   2.2 Oct. 06, 2002
 *				 Commented
 *  </PRE>
 *
 *	Collaboration Statement:
 *    I worked on the homework assignment alone, using only             
 *    course materials.
 *  
 *  Created with JCreatorLE, some indents are off when viewed through notepad
 *    or EMACS
 *
 *  @author <A HREF="mailto:gtg184g@mail.gatech.edu">Jose Manuel Caban</A>
 *  @version Version 2.2, Oct. 06, 2002
 */

import java.io.*;

public class FileChanger {
  
  //variables
  private String strFileName;
  
  //readers and writers
  FileInputStream 		fis;
  ObjectInputStream 	ois;
  
  FileOutputStream		fos;
  ObjectOutputStream	oos;
  
  public static final boolean bDebug = false; //there's nothing to debug
  											  //that bDebug can handle
  
  ////////////////
  //Constructors//
  ////////////////
  
  /**
   *Constructor for FileChanger
   *@param strFileName the name to be given to the output file
   */
  public FileChanger(String strFileName){
  	this.strFileName = strFileName;
  }
  
  ////////////////////////////
  //Initializers/Destructors//
  ////////////////////////////
  
  /**
   *Initialize the reader streams
   *@return true if successful, false if file not found
   */
  public boolean initReader(){
  	
  	//init file input stream
  	try{
  		fis = new FileInputStream(strFileName);
  	}
  	catch(FileNotFoundException fnfe){
  		return false;
  	}
  	
  	//init obj input stream
  	try{
  		ois = new ObjectInputStream(fis);
  	}
  	catch(IOException ioe){
  		return false;
  	}
  	return true;	
  }
  
  /**
   *Initialize the write streams
   */
  public void initWriter(){
  	
  	//init file output stream
  	try{
  		fos = new FileOutputStream(strFileName);
  	}
  	catch(FileNotFoundException fnfe){
  		System.err.println("File not Found! - initWriter()");
  	}
  	
  	//init obj output stream
  	try{
  		oos = new ObjectOutputStream(fos);
  	}
  	catch(IOException ioe){
  		System.err.println("IOException - initWriter()");
  	}  	  	
  }
  
  /**
   *Close read streams
   */
  public void closeRead(){
  	
  	try{
  		fis.close();
  	}
  	catch(IOException ioe){
  		System.err.println("IOException - closeRead()");
  	}  	
  }
  
  /**
   *Close write streams
   */
  public void closeWrite(){
  	
  	try{
  		oos.flush();
  	}
  	catch(IOException ioe){
  		System.err.println("IOException - flush objstream - closeWrite()");
  	}
  	
  	try{
  		fos.close();
  	}
  	catch(IOException ioe){
  		System.err.println("IOException - close filestream - closeWrite()");
  	}
  }
  
  ///////////
  //Methods//
  ///////////
  
  /**
   *Retrieve the next object in the file
   */
  public Object nextObject(){
  	try{
  		return ois.readObject();
  	}
  	catch(EOFException eof){
  		return null;
  	}
  	catch(ClassNotFoundException cnfe){
  		System.err.println("Class not found - nextObject()");
  		return null;
  	}
  	catch(IOException ioe){
  		System.err.println("IO Exception - nextObject()");
  		return null;
  	}
  	catch(NullPointerException npe){
  		System.err.println("Null Pointer Exception - nextObject()");
  		return null;
  	}
  		
  }
  
  /**
   *Write an Object to the file
   *@param toWrite, the object to be written
   */
  public void writeObject(Object toWrite){
  	try{
  		oos.writeObject(toWrite);
  	}
  	catch(IOException ioe){
  		System.err.println("IO Exception - writeObject()");
  	}
  }
  
  /**********************************************************/
  
  /**
   *  Debugging main for class FileChanger.  
   *  This method will rigorously test my code.
   *
   *  <br><br>
   *  @param args a String array of command line arguments.
   */
  public static void main(String[] args) {
    FileChanger fg = new FileChanger("This stinks.txt");
    
    fg.initReader();
    fg.initWriter();
    
    fg.writeObject(new Integer(7));
    fg.writeObject(new Integer(6));
    fg.writeObject(new String("Bob is a person too"));
    fg.writeObject(new Boolean(false));
    
    System.out.println(fg.nextObject());
    System.out.println(fg.nextObject());
    System.out.println(fg.nextObject());
    System.out.println(fg.nextObject());
    System.out.println(fg.nextObject());
    
    fg.closeRead();
    fg.closeWrite();
    
    
  }// end of main(String[] args)

}// end of class FileChanger