varargs don’t seem to work

[flying-sheep]

>>> from jnius import autoclass
>>> syso = autoclass('java.lang.System').out
>>> syso.println("hi")
hi
>>> syso.printf("hi\n")
/usr/lib/python2.7/site-packages/jnius/jnius.so in jnius.JavaMultipleMethod.__call__ (jnius/jnius.c:14462)()
JavaException: No methods matching your arguments
>>> syso.printf("hi %s\n", "jnius")
/usr/lib/python2.7/site-packages/jnius/jnius.so in jnius.JavaMultipleMethod.__call__ (jnius/jnius.c:14462)()
JavaException: No methods matching your arguments

[flying-sheep]

also System.out.print is a syntax error without from __future__ import print_function, but that isn’t important ;)

if we’d really need it, we could use autoclass('java.lang.System').out.__getattribute__("print")("woo")

[tshirtman]

Confirmed, thanks for reporting, looking into how to add this to our method signature lookup :)

[flying-sheep]

nice. please remember to create tags as soon as bigger features like that (or the upcoming import hook) come in, they help with knowing when to package a new version.

[jishi9]

As an aid for adding this feature (and also as a work around) you can do the following:

# Empty vararg
System = autoclass('java.lang.System')
System.out.printf('string' ,[])

# Note: Using python strings does NOT work
String = autoclass('java.lang.String')
System.out.printf('my string is %s', [ String('this') ])

The reason for this is that Java internally converts the varargs into a single array parameter.

Also note that in addition to getting printed to stdout/stderr, calling printf also seems to return a PrintStream object. I am assuming that some special-case code ensures that this does not happen with print and println?

[tshirtman]

Thanks for the list tip, i was there too :)

Our parser currently doesn't know if a list in signature is a varargs list or not, seems we are not the first ones to run into this issue, if we can detect that, it should be easy enought to adjust our calculate_score method.

For the unability to build a list of python strings directly, i was about to open a bug report, at least to discuss those workarounds and if we can find a better solution (same issue with building lists of numbers and probably other things).

edit: found about isVarArgs, that allow at least to know if a method is varargs… :)

[flying-sheep]

We should convert between python and Java strings always and implicitly. Trying to use autoclass on java.lang.String should yield a warning that you'll be dealing with python strings no matter what you do.

Reason is that python strings can do anything Java strings can do, and this change would make anything easier.

Btw.: so you already translate toString to __str__?

[tshirtman]

Ok! sorry it took so long, but we now have at least some basic support of varargs in the varargs_support branch, test case for printf as been added, more test cases with more exotic objects welcome :)

[tshirtman]

I'll close this since support has been added, feel free to reopen if support is incomplete.