test classmethod

contextDecorator3.py

#!/usr/bin/env python

from abc import ABCMeta, abstractmethod
from functools import wraps
import time


class ContextDecorator(object):

    _built = False

    def __init__(self, *args, **kwargs):
        self.args = args
        self.__dict__.update(kwargs)
        self._contextExists = False
        self._rebuild = kwargs.get('rebuild', False)

    @abstractmethod
    def _build(self):
        pass

    @abstractmethod
    def _destroy(self):
        pass

    def clear_built(self):
        ContextDecorator._built = False

    def __enter__(self):

        if not ContextDecorator._built or self._rebuild:
            try:
                self._build()
            except:
                self.clear_built()
                raise
            ContextDecorator._built = True
            print 'call _build first time'
        else:
            print 'skip _build'
            self._contextExists = True

        return self

    def __exit__(self, typ, val, traceback):
        if not self._contextExists or self._rebuild:
            try:
                self._destroy()
            except:
                self.clear_built()
                raise

            self.clear_built()
            print 'call _destroy first time'
        else:
            print 'skip _destroy'
            self._contextExists = False

    def __call__(self, f):
        self.function = f

        @wraps(f)
        def wrapper(*args, **kw):

            with self:
                try:
                    return f(*args, **kw)
                except:
                    self.clear_built()
                    raise
        return wrapper


class CustomContext(ContextDecorator):

    def __init__(self, *args, **kwargs):
        super(CustomContext, self).__init__(*args, **kwargs)

    def _build(self):
        pass

    def _destroy(self):
        pass


print 'context manager test'
try:
    with CustomContext():
        for i in range(3):
            with CustomContext():
                time.sleep(0.01)

except:
    print 'caught exception'
    print CustomContext._built


print '-' * 10
print 'context manager test always rebuild'

try:
    with CustomContext(rebuild=True):
        for i in range(3):
            with CustomContext(rebuild=True):
                time.sleep(0.01)
except:
    print 'caught exception'
    print CustomContext._built

print '-' * 10
print 'decorator test', CustomContext._built, ContextDecorator._built
# print CustomContext._built


@CustomContext()
@CustomContext()
def test():
    print 'in side test func'

try:
    test()
except:
    print 'caught exception', CustomContext._built


print '-' * 10
print 'decorator test rebuild=True', CustomContext._built, ContextDecorator._built


@CustomContext(rebuild=True)
@CustomContext(rebuild=True)
def test1():
    print 'in side test func'

try:
    test1()
except:
    print 'caught exception', CustomContext._built
    # raise