cybertools/util/aop.txt

=======================================
Aspect-oriented Programming for Dummies
=======================================

$Id$

  >>> from cybertools.util.aop import getNotifier

  >>> class Demo(object):
  ...     def foo(self, num):
  ...         return 38 + num

  >>> demo = Demo()
  >>> demo.foo(4)
  42

  >>> wrappedFoo = getNotifier(demo.foo)
  >>> demo.foo is wrappedFoo
  True

Repeated calls of ``getNotifier()`` return the same wrapped object.

  >>> getNotifier(demo.foo) is wrappedFoo
  True

Calling the wrapped method still works.

  >>> demo.foo(8)
  46

We can now get information about the returning of the method by
subscribing to it using some log function.

  >>> def log(result, msg):
  ...     print 'logging: %s, result=%s' % (msg, str(result))

  >>> demo.foo.subscribe(log, None, 'before foo')

  >>> demo.foo(4)
  logging: before foo, result=None
  42

  >>> demo.foo.subscribe(log, log, "that's foo")
  >>> demo.foo(4)
  logging: before foo, result=None
  logging: that's foo, result=None
  logging: that's foo, result=42
  42


Wrapping methods on class level
===============================

  >>> demo = Demo()
  >>> demo.foo(4)
  42

  >>> getNotifier(Demo.foo)
  <...Notifier object ...>
  >>> Demo.foo.subscribe(None, log, 'after foo')
  >>> demo.foo(4)
  logging: after foo, result=42
  42