code: public Integer evaluate(float fraction, Integer startValue, Integer endValue) {
          int startInt = startValue;
          return (int)(startInt + fraction * (endValue - startInt));
      }
docs: This function returns the result of linearly interpolating the start and end values, with
  <code>fraction</code> representing the proportion between the start and end values. The
  calculation is a simple parametric calculation: <code>result = x0 + t * (v1 - v0)</code>,
  where <code>x0</code> is <code>startValue</code>, <code>x1</code> is <code>endValue</code>,
  and <code>t</code> is <code>fraction</code>.
  
  @param fraction   The fraction from the starting to the ending values
  @param startValue The start value; should be of type <code>int</code> or
  <code>Integer</code>
  @param endValue   The end value; should be of type <code>int</code> or <code>Integer</code>
  @return A linear interpolation between the start and end values, given the
  <code>fraction</code> parameter.