Interface & Implementation

Lie Ryan lie.1296 at gmail.com
Fri Dec 12 22:48:09 CET 2008


On Fri, 12 Dec 2008 16:07:26 +0530, J Ramesh Kumar wrote:

> Hi,
> 
> I am new to python. I require some help on implementing interface and
> its implementation. I could not find any sample code in the web. Can you
> please send me some sample code which is similar to the below java code
> ? Thanks in advance for your help.
> 
> ............
> public interface MyIfc
> {
>     public void myMeth1();
>     public void myMeth2();
> }
> ....
> public class MyClass implements MyIfc {
>       public void myMeth1()
>       {
>           //do some implementation
>       }
> 
>      public void myMeth2()
>        {
>            //do some implementation
>        }
> }

There is no need for interface in python due to duck typing 

class MyClass1(object):
    def myMeth1(self): 
        # some implementation
    def myMeth2(self):
        # some implementation
class MyClass2(object):
    def myMeth1(self): 
        # other implementation
    def myMeth2(self):
        # other implementation

cs[0] = MyClass1()
cs[1] = MyClass2()
for c in cs: 
    c.myMeth1()
    c.myMeth2()

but if you really want it, simple inheritance might be better anyway, 
though not really pythonic:

class MyIfc(object):
    def myMeth1(self): return NotImplemented
    def myMeth2(self): return NotImplemented
class MyClass(MyIfc):
    def myMeth1(self): 
        # some implementation
    def myMeth2(self):
        # some implementation

# some might notice the (ab)use of NotImplemented sentinel there




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