from datetime import date, time, timedelta
def make_immutable(value):
if isinstance(value, (int, long, date, time, timedelta, basestring, buffer)): return value
if isinstance(value, (list, tuple)): return tuple([make_immutable(x) for x in value])
if isinstance(value, dict):
class DictTuple(tuple): pass
return DictTuple([(make_immutable(k), make_immutable(v)) for k, v in value.iteritems()])
raise NotImplemented()
class CacheCaller(object):
def __init__(self, acallable):
self.acallable = acallable
self.cache = {}
def __call__(self, *args, **kwargs):
key = (make_immutable(args), make_immutable(kwargs))
if key in self.cache:
result = self.cache[key]
else:
result = self.acallable(*args, **kwargs)
self.cache[key] = result
return result
def example():
# slow operation
def get_value(param1, param2, param3, param4):
from time import sleep
sleep(1)
return '%s %s %s %s' % (param1, param2, param3, param4)
# not a good idea to do it repeatly
print get_value(1, 'string', [1,2,3], {'one': 1, 'two': 2, 'three': 3})
print get_value(1, 'string', [1,2,3], {'one': 1, 'two': 2, 'three': 3})
print get_value(1, 'string', [1,2,3], {'one': 1, 'two': 2, 'three': 3})
print get_value(1, 'string', [1,2,3], {'one': 1, 'two': 2, 'three': 3})
print get_value(1, 'string', [1,2,3], {'one': 1, 'two': 2, 'three': 3})
# make it faster with cache
caller = CacheCaller(get_value)
print caller(1, 'string', [1,2,3], {'one': 1, 'two': 2, 'three': 3})
print caller(1, 'string', [1,2,3], {'one': 1, 'two': 2, 'three': 3})
print caller(1, 'string', [1,2,3], {'one': 1, 'two': 2, 'three': 3})
print caller(1, 'string', [1,2,3], {'one': 1, 'two': 2, 'three': 3})
print caller(1, 'string', [1,2,3], {'one': 1, 'two': 2, 'three': 3})
