Parsing String Representation of Number Literal with Suffices

[Joshua Smith]

Here are examples of parsing String literal representations of numeric literals with suffixes. Why does parsing a float from 1f and 1d work, but parsing a float from 1L fail and parsing bytes from 1L, 1f and 1d all fail?

  
float f1 = Float.parseFloat("1L"); // compiles, but throws NumberFormatException: For input string: "1L"
float f2 = Float.parseFloat("1f"); // fine (result 1.0)
float f3 = Float.parseFloat("1d"); // fine (result 1.0)
 
byte b1 = Byte.parseByte("1L"); // compiles, but throws NumberFormatException: For input string: "1L"
byte b2 = Byte.parseByte("1f"); // compiles, but throws NumberFormatException: For input string: "1f"
byte b3 = Byte.parseByte("1d"); // compiles, but throws NumberFormatException: For input string: "1d"

Thanks,
Josh

[Ryan Kade]

The parse functions of the wrapper classes require that the input string be parseable text that is equivalent to the corresponding primitive. You couldn't actually assign a double, long, or float to a byte, so why should Byte let you do it via a String?
[ August 24, 2005: Message edited by: Ryan Kade ]

[Joshua Smith]

I guess I was expecting a different error message since the String is technically parsable as a number.

Still you're right. Those assignments can't be made without an explicit cast.

Josh

[Ryan Kade]

True, the strings are technically parseable as a number, but that's not what the contract specifies.

The SDK docs for Integer.parseInt say an exception is thrown if "The value represented by the string is not a value of type int." You'll find similar language in each of the wrapper class docs.

[Joshua Smith]

Excellent. Thanks Ryan.