How to determine the type of primitive in a String representation?

Question

I have a String representation of a primitive and my goal is to determine which primitive is it.
My function is as follows:

public Object getPrimitive(String primitiveAsString) {
.....
}

So for example I would like to return an integer in case the input is "223" but a double if the input is "223.1" or even "223.0"(!!). Moreover, I would like to separate between float and double and even between integer and "BigInteger".

I have tried a solution using NumberFormat and it didn't work for me....

Is there an elegant way to do so?

Thanks!

Answer 1

An idea is just trying to return each type in try-catch.

Code: (the error-checking may be less than ideal)

public static void main(String[] args)
{
    System.out.println(getPrimitive("123")); // Byte
    System.out.println(getPrimitive("1233")); // Short
    System.out.println(getPrimitive("1233587")); // Integer
    System.out.println(getPrimitive("123.2")); // Float
    System.out.println(getPrimitive("123.999999")); // Double
    System.out.println(getPrimitive("12399999999999999999999999")); // BigInteger
    System.out.println(getPrimitive("123.999999999999999999999999")); // BigDecimal
}

static public Object getPrimitive(String string)
{
  try { return Byte.valueOf(string);       } catch (Exception e) { };
  try { return Short.valueOf(string);      } catch (Exception e) { };
  try { return Integer.valueOf(string);    } catch (Exception e) { };
  try { return new BigInteger(string);     } catch (Exception e) { };
  try { if (string.matches(".{1,8}"))
          return Float.valueOf(string);    } catch (Exception e) { };
  try { if (string.matches(".{1,17}"))
          return Double.valueOf(string);   } catch (Exception e) { };
  try { return new BigDecimal(string);     } catch (Exception e) { };
  // more stuff ?
  return null;
}

The reasoning behind .{1,8} and .{1,17} is that float and double are accurate to about 7 and 16 digits each (according to some random source). . is a wild-card. {x,y} means repeated between x and y times.

EDIT:

Improved to differentiate float, double and BigDecimal with a basic regex among other things.