class CoapLFUCache(Cache):
def __init__(self, mode, max_dim):
"""
Initialise an LFU cache for the Coap.
:param max_dim: max number of elements in the cache
:param mode: used to differentiate between a cache used in a forward-proxy or in a reverse-proxy
"""
Cache.__init__(self, mode, max_dim)
self.cache = LFUCache(maxsize=max_dim)
def __str__(self):
msg = []
for e in list(self.cache.values()):
msg.append(str(e))
return ("Cache Size: {sz}\n" + "\n".join(msg))
def debug_print(self):
"""
:return: a debug printout for the current cache.
"""
return ("size = %s\n%s" % (
self.cache.currsize,
'\n'.join([
( "element.max age %s\n"\
"element.uri %s\n"\
"element.freshness %s" ) % (
element.max_age,
element.uri,
element.freshness )
for key, element
in list(self.cache.items())
])))
class TwitterListener(StreamListener):
def __init__(self):
self.cache = LFUCache(maxsize=50)
self.cache2 = LFUCache(maxsize=50)
Timer(interval=60, function=self.print_keys)
Timer(interval=30, function=self.check_cached_words)
def on_data(self, data):
data_lst = json.loads(data)
data_lst = data_lst.get('text', '').split()
if self.cache.currsize == self.cache.maxsize:
for key in list(self.cache.keys()):
if self.cache[key] == 0:
del self.cache[key]
for word in data_lst:
if word in self.cache.keys():
self.cache[word] += 1
else:
self.cache[word] = 1
if self.cache[word] < 0:
del self.cache[word]
return True
def print_keys(self):
"""
print recent words and update the second cache every 60 seconds
"""
print(list(self.cache.items()))
self.cache2.update(self.cache)
return True
def check_cached_words(self):
"""
Decrease score of word by 1 if the score does not change within
60 seconds
"""
for word in list(self.cache.keys()):
if self.cache.get(word) == self.cache2.get(word):
self.cache[word] -= 1
return True
class CoapLFUCache(CoapCache):
def __init__(self, max_dim):
"""
:param max_dim:
"""
print "Using LFU Cache with dimension : " + str(max_dim)
self.cache = LFUCache(maxsize=max_dim)
def update(self, key, element):
"""
:param key:
:param element:
:return:
"""
print "updating cache"
print "key: ", key.hashkey
print "element: ", element
self.cache.update([(key.hashkey, element)])
def get(self, key):
"""
:param key:
:return: CacheElement
"""
try:
response = self.cache[key.hashkey]
except KeyError:
print "problem here"
response = None
return response
def is_full(self):
"""
:return:
"""
if self.cache.currsize == self.cache.maxsize:
return True
return False
def is_empty(self):
"""
:return:
"""
if self.cache.currsize == 0:
return True
return False
def debug_print(self):
"""
:return:
"""
print "size = ", self.cache.currsize
list = self.cache.items()
for key, element in list:
print "element.max age ", element.max_age
print "element.uri", element.uri
print "element.freshness ", element.freshness
