/**
   A class that can compute the value of an arithmetic expression.
*/
public class Evaluator
{
   /**
      Constructs an evaluator.
      @param anExpression a string containing the expression
      to be evaluated
   */
   public Evaluator(String anExpression)
   {
      tokenizer = new ExpressionTokenizer(anExpression);
   }

   /**
      Evaluates the expression.
      @return the value of the expression.
   */
   public int getExpressionValue()
   {
   }

   /**
      Evaluates the next term found in the expression.
      @return the value of the term
   */
   public int getTermValue()
   {
   }

   /**
      Evaluates the next factor found in the expression.
      @return the value of the factor
   */
   public int getFactorValue()
   {
   }

   private ExpressionTokenizer tokenizer;
}