Re: [Jython-users] Static methods?

[Kevin B. <kb...@ca...>]

Humbel Otmar wrote:
> 
> [ John Goerzen ]
> >
> > Another question (sorry about all of these!)
> >
> > I'm porting more Java code to Jython.  I've got a case like:
> >
> > public static String myfunc(String id)
> >
> > I'm unsure how to do a static method in Jython.  Do I declare it in my
> > .py oustide the class: area with a @sig that has static in it?
> 
> Just inside the class, but **without** the self parameter. Given file
> Foo.py:

No - this does _not_ work in any version of Python/Jython I've used:

Jython 2.1a1 on java1.3.0 (JIT: null)
Type "copyright", "credits" or "license" for more information.
>>> class X:
...   def go( id ):
...     print "called:", id
... 
>>> X.go( "asdf" )
Traceback (innermost last):
  File "<console>", line 1, in ?
TypeError: unbound method go() must be called with instance as first argument
>>>

The 'self' parameter is not a keyword - it is a convention.  Methods on class X require an X instance:

>>> X.go( X() )
called: <__main__.X instance at 5991085>
>>> 

What you can do is cheat in one of two ways:

class XGo:
    """Callable object to act as a static method"""
    def __call__( self, id ):
        print "called XGo(%s)" % id

class XStatics:
    def go( self, id ):
        """Use the bound method as a static method"""
        print "called XStatics.go(%s)" % id
    # ... and other "static" methods


class X:
    go = XGo()
    __xstatics = XStatics()
    go2=__xstatics.go
    # ... and other static methods

X.go( "asdf" )
X.go2( "zxcv")

Then executing that from emacs:

Jython 2.1a1 on java1.3.0 (JIT: null)
Type "copyright", "credits" or "license" for more information.
## working on region in file d:/TEMP/python-289AX1...
>>> called XGo(asdf)
called XStatics.go(zxcv)
>>> 

kb