class BaseCache(object):
"""
BaseCache is a class that saves and operates on an OrderedDict. It has a
certain capacity, stored in the attribute `maxsize`. Whether this
capacity is reached, can be checked by using the boolean property
`is_full`. To implement a custom cache, inherit from this class and
override the methods ``__getitem__`` and ``__setitem__``.
Call the method `sunpy.database.caching.BaseCache.callback` as soon
as an item from the cache is removed.
"""
__metaclass__ = ABCMeta
def __init__(self, maxsize=float('inf')):
self.maxsize = maxsize
self._dict = OrderedDict()
def get(self, key, default=None): # pragma: no cover
"""Return the corresponding value to `key` if `key` is in the cache,
`default` otherwise. This method has no side-effects, multiple calls
with the same cache and the same passed key must always return the same
value.
"""
try:
return self._dict[key]
except KeyError:
return default
@abstractmethod
def __getitem__(self, key):
"""abstract method: this method must be overwritten by inheriting
subclasses. It defines what happens if an item from the cache is
attempted to be accessed.
"""
return # pragma: no cover
@abstractmethod
def __setitem__(self, key, value):
"""abstract method: this method must be overwritten by inheriting
subclasses. It defines what happens if a new value should be assigned
to the given key. If the given key does already exist in the cache or
not must be checked by the person who implements this method.
"""
@abstractproperty
def to_be_removed(self):
"""The item that will be removed on the next
:meth:`sunpy.database.caching.BaseCache.remove` call.
"""
@abstractmethod
def remove(self):
"""Call this method to manually remove one item from the cache. Which
item is removed, depends on the implementation of the cache. After the
item has been removed, the callback method is called.
"""
def callback(self, key, value):
"""This method should be called (by convention) if an item is removed
from the cache because it is full. The passed key and value are the
ones that are removed. By default this method does nothing, but it
can be customized in a custom cache that inherits from this base class.
"""
@property
def is_full(self):
"""True if the number of items in the cache equals :attr:`maxsize`,
False otherwise.
"""
return len(self._dict) == self.maxsize
def __delitem__(self, key):
self._dict.__delitem__(key)
def __contains__(self, key):
return key in self._dict.keys()
def __len__(self):
return len(self._dict)
def __iter__(self):
for key in self._dict.__iter__():
yield key
def __reversed__(self): # pragma: no cover
for key in self._dict.__reversed__():
yield key
def clear(self): # pragma: no cover
return self._dict.clear()
def keys(self): # pragma: no cover
return self._dict.keys()
def values(self): # pragma: no cover
return self._dict.values()
def items(self): # pragma: no cover
return self._dict.items()
def iterkeys(self): # pragma: no cover
return self._dict.iterkeys()
def itervalues(self): # pragma: no cover
for value in self._dict.itervalues():
yield value
def iteritems(self): # pragma: no cover
for key, value in self._dict.iteritems():
yield key, value
def update(self, *args, **kwds): # pragma: no cover
self._dict.update(*args, **kwds)
def pop(self,
key,
default=MutableMapping._MutableMapping__marker
): # pragma: no cover
return self._dict.pop(key, default)
def setdefault(self, key, default=None): # pragma: no cover
return self._dict.setdefault(key, default)
def popitem(self, last=True): # pragma: no cover
return self._dict.popitem(last)
def __reduce__(self): # pragma: no cover
return self._dict.__reduce__()
def copy(self): # pragma: no cover
return self._dict.copy()
def __eq__(self, other): # pragma: no cover
return self._dict.__eq__(other)
def __ne__(self, other): # pragma: no cover
return self._dict.__ne__(other)
def viewkeys(self): # pragma: no cover
return self._dict.viewkeys()
def viewvalues(self): # pragma: no cover
return self._dict.viewvalues()
def viewitems(self): # pragma: no cover
return self._dict.viewitems()
@classmethod
def fromkeys(cls, iterable, value=None): # pragma: no cover
return OrderedDict.fromkeys(iterable, value)
def __repr__(self): # pragma: no cover
return '{0}({1!r})'.format(self.__class__.__name__, dict(self._dict))
def setdefault(self, key, default=None):
"""Overide .setdefault() to perform case-insensitively"""
return OrderedDict.setdefault(self, key.lower(), default)
class BaseCache(object):
"""
BaseCache is a class that saves and operates on an OrderedDict. It has a
certain capacity, stored in the attribute `maxsize`. Whether this
capacity is reached, can be checked by using the boolean property
`is_full`. To implement a custom cache, inherit from this class and
override the methods ``__getitem__`` and ``__setitem__``.
Call the method `sunpy.database.caching.BaseCache.callback` as soon
as an item from the cache is removed.
"""
__metaclass__ = ABCMeta
def __init__(self, maxsize=float('inf')):
self.maxsize = maxsize
self._dict = OrderedDict()
def get(self, key, default=None): # pragma: no cover
"""Return the corresponding value to `key` if `key` is in the cache,
`default` otherwise. This method has no side-effects, multiple calls
with the same cache and the same passed key must always return the same
value.
"""
try:
return self._dict[key]
except KeyError:
return default
@abstractmethod
def __getitem__(self, key):
"""abstract method: this method must be overwritten by inheriting
subclasses. It defines what happens if an item from the cache is
attempted to be accessed.
"""
return # pragma: no cover
@abstractmethod
def __setitem__(self, key, value):
"""abstract method: this method must be overwritten by inheriting
subclasses. It defines what happens if a new value should be assigned
to the given key. If the given key does already exist in the cache or
not must be checked by the person who implements this method.
"""
@abstractproperty
def to_be_removed(self):
"""The item that will be removed on the next
:meth:`sunpy.database.caching.BaseCache.remove` call.
"""
@abstractmethod
def remove(self):
"""Call this method to manually remove one item from the cache. Which
item is removed, depends on the implementation of the cache. After the
item has been removed, the callback method is called.
"""
def callback(self, key, value):
"""This method should be called (by convention) if an item is removed
from the cache because it is full. The passed key and value are the
ones that are removed. By default this method does nothing, but it
can be customized in a custom cache that inherits from this base class.
"""
@property
def is_full(self):
"""True if the number of items in the cache equals :attr:`maxsize`,
False otherwise.
"""
return len(self._dict) == self.maxsize
def __delitem__(self, key):
self._dict.__delitem__(key)
def __contains__(self, key):
return key in self._dict.keys()
def __len__(self):
return len(self._dict)
def __iter__(self):
for key in self._dict.__iter__():
yield key
def __reversed__(self): # pragma: no cover
for key in self._dict.__reversed__():
yield key
def clear(self): # pragma: no cover
return self._dict.clear()
def keys(self): # pragma: no cover
return self._dict.keys()
def values(self): # pragma: no cover
return self._dict.values()
def items(self): # pragma: no cover
return self._dict.items()
def iterkeys(self): # pragma: no cover
return self._dict.iterkeys()
def itervalues(self): # pragma: no cover
for value in self._dict.itervalues():
yield value
def iteritems(self): # pragma: no cover
for key, value in self._dict.iteritems():
yield key, value
def update(self, *args, **kwds): # pragma: no cover
self._dict.update(*args, **kwds)
def pop(self, key, default=MutableMapping._MutableMapping__marker): # pragma: no cover
return self._dict.pop(key, default)
def setdefault(self, key, default=None): # pragma: no cover
return self._dict.setdefault(key, default)
def popitem(self, last=True): # pragma: no cover
return self._dict.popitem(last)
def __reduce__(self): # pragma: no cover
return self._dict.__reduce__()
def copy(self): # pragma: no cover
return self._dict.copy()
def __eq__(self, other): # pragma: no cover
return self._dict.__eq__(other)
def __ne__(self, other): # pragma: no cover
return self._dict.__ne__(other)
def viewkeys(self): # pragma: no cover
return self._dict.viewkeys()
def viewvalues(self): # pragma: no cover
return self._dict.viewvalues()
def viewitems(self): # pragma: no cover
return self._dict.viewitems()
@classmethod
def fromkeys(cls, iterable, value=None): # pragma: no cover
return OrderedDict.fromkeys(iterable, value)
def __repr__(self): # pragma: no cover
return '{0}({1!r})'.format(self.__class__.__name__, dict(self._dict))
def setdefault(self, key, default=None):
"""Overide .setdefault() to perform case-insensitively"""
return OrderedDict.setdefault(self, key.lower(), default)