core.cache

Lightweight Least Recently Used (LRU) cache used by core components.

This module provides a minimal LRU cache implementation backed by collections.OrderedDict. It is intended for small, fast caches such as operation-result caching inside FuzznumStrategy instances.

class axisfuzzy.core.cache.LruCache(maxsize=None)

Bases: object

Simple Least Recently Used (LRU) cache.

The cache stores mapping from keys to values and evicts the least recently used item when capacity is exceeded.

Parameters:

maxsize (int, optional) – Maximum number of items to hold in the cache. If None, the value from axisfuzzy.config.get_config().CACHE_SIZE is used.

maxsize

Configured maximum number of entries.

Type:

int

_cache

Internal mapping preserving access/insertion order.

Type:

collections.OrderedDict

Notes

• Keys must be hashable.

• get returns None for missing keys (no exception raised).

Examples

>>> from axisfuzzy.core.cache import LruCache
>>> c = LruCache(maxsize=2)
>>> c.put('a', 1)
>>> c.put('b', 2)
>>> c.get('a')
1
>>> c.put('c', 3)  # least recently used ('b') evicted if 'a' was accessed
>>> 'b' in c
False

get(key)

Retrieve a value and mark the key as recently used.

Parameters:

key (str) – Key to lookup in the cache.

Returns:

The stored value if the key exists, otherwise None.

Return type:

Any or None

Examples

>>> c = LruCache(maxsize=2)
>>> c.put('x', 10)
>>> c.get('x')
10
>>> c.get('missing') is None
True

put(key, value)

Insert or update a key-value pair in the cache.

If the key already exists, it is updated and moved to the most-recently-used position. If adding a new item causes the cache to exceed maxsize, the least recently used item is evicted.

Parameters:

• key (str) – Cache key to insert or update.

• value (Any) – Value to associate with the key.

Raises:

ValueError – If maxsize is configured as a non-positive integer (depends on config).

Return type:

None

Examples

>>> c = LruCache(maxsize=1)
>>> c.put('a', 1)
>>> c.put('a', 2)  # update existing key
>>> c.get('a')
2