public static Vector formatDecimal(Collection c, String pattern) {
    DecimalFormat f = new DecimalFormat(pattern);
    Vector v = new Vector();
    for (Object o : c) {
      if (o instanceof Double) {
        v.add(f.format(o));
      } else {
        v.add(o);
      }
    }
    return v;
  }
Centers the given string on the <code>PrintWriter</code>

@param s the string to center
@param pw the <code>PrintWriter</code> to print with
geode-junit/src/main/java/perffmwk/Formatter.java