// package com.wrox.util;

// From "Professional Java Server Programming", Patzer et al.,
// pp 33-34.

public class JO_LoanTools
{

   public static float stringToFloat (String inputString)
          throws NumberFormatException
   {
      Float f = new Float (inputString);
      return f.floatValue ();
   }

   public static int calculateLoanPeriod (float principal, float interest,
                                          float payment)
          throws IllegalArgumentException
   {
      int months = 0;

      float balance = principal;

      // quick and dirty loop to calculate the loan period
      while (balance > 0)
      {
         balance += ((balance * interest) / 12);  //  Add interest
         balance -= payment;                      //  Subtract payment
         months  += 1;                             //  Increment months

         // check to see if the repayments are working,
         // or if the interest is pushing the balance up higher
         if (balance >= principal)
         {
            throw new IllegalArgumentException ("The values entered will "
                       + "not ever allow the loan to be paid off.");
         }
      }
      return months;
   }
}