[java] Method signature precision

pycoucou · 06-17-2004, 06:11 AM

I used to believe that the java method signature was basically
- return type
- name of the method
- parameters

But the following error:

Matrix.java:851: convertArray(float[][]) is already defined in Matrix
public static double[][] convertArray (float[][] array) {

indicates that finally, it's rather name of the method + parameters!

Have you a tip to overgo this issue to use convertArray without thinking of the type of data I'm handling...

Cheers,
PY

moeminhtun · 06-17-2004, 09:39 PM

What u wanna do exactly?

pycoucou · 06-18-2004, 03:30 AM

Well... is there a way to create a convertArray method that typecast each elements (ie float[] -> double[], float[] ->int[] +rounding for this one, etc...)

I want to be able to define:
public double[][] convertArray(float[][] array)
public int[][] convertArray(float[][] array)

But it seems, according to javac, it's not possible... Has someone an idea on that? ie is it possible or I'll have to use a method with another name (float2int)...

Cheers,
PY

deiussum · 06-18-2004, 08:20 AM

Yes, that's right. You cannot overload functions to have the same name/parameters, but different return types. For instance, if you took your 2 methods there, and simply tried to call them w/o storing the return types like so:

convertArray(someFloatArray);

How would the compiler know which overload to call?

Anyway, a solution to your problem could be just to give the functions different names, such as convertArrayToDouble and convertArrayToInt.

pycoucou · 06-18-2004, 08:33 AM

Quote:

Originally posted by deiussum
Yes, that's right. You cannot overload functions to have the same name/parameters, but different return types. For instance, if you took your 2 methods there, and simply tried to call them w/o storing the return types like so:

convertArray(someFloatArray);

How would the compiler know which overload to call?

Anyway, a solution to your problem could be just to give the functions different names, such as convertArrayToDouble and convertArrayToInt.

I agree with you... I believed that i could overload this function as soon as the return type was different, it seems that not... Thanks for this precision. I'm disappointed that my first guess was wrong

eric.r.turner · 06-19-2004, 10:39 PM

Overloading resolution only cares about the method name and argument types, not the return type. There is no getting around "...thinking of the data type [you're] handling." Perhaps you could have methods like:

public double[][] convertArrayToDouble( float[][] f );
public double[][] convertArrayToDouble( int[][] i );
public int[][] convertArrayToInt( float[][] f );

coolman0stress · 06-20-2004, 11:31 AM

Yes, just have more accurate method descriptions. Or put them in different classes.