package jspexamples;

import java.util.*;
import java.io.*;

/**
 * Computes the fiboacci series, returns the next value as a bean.
 * Developed as an example for SWE 642, November 2000
 *
 * @author Jeff Offutt
 * @version 2.0
 * 22-March-2009
*/

public class fiboBean
{
// These are inner variables, not class variables.
private int N, Nminus1, Nminus2;


public static void main (String args[])
{  // for testing.
   int fib_val;
   fiboBean fb = new fiboBean();

   for (int i=0;/* loop until exception */ ;i++)
   {
      try
      {
         fib_val = fb.getFibo ();
	 System.out.println (i + ": " + fib_val);
      }
      catch (overflowException e)
      {
         System.out.println (e);
	 break; // from for loop
      }
   }  // for
} // end of main

/**
 * Default constructor initializes the recursion.
 * Nminus1 and Nminus2 are the previous two values.
 * N counts how many Fibonacci values have been returned.
 * @author Jeff Offutt
 */
public fiboBean ()
{
   Nminus1 = 1;
   Nminus2 = 1;
   N = 0;
}

/**
 * The getter computes and returns the next value
 * in the Fibonacci series. When we overflow, that tells
 * the client that we are finished.
 * @author Jeff Offutt
 */
public int getFibo () throws overflowException
{
   int ret_val;
   if (N==0 || N==1)
   {
      N++;
      ret_val = 1;
   }
   else
   {
      ret_val = Nminus1+Nminus2;
      if (ret_val < 0)
         throw new overflowException ("Integer overflow");
      N++;
      Nminus2 = Nminus1;
      Nminus1 = ret_val;
   }
   return (ret_val);
}  // end of GetFibo

} //end of class