rename EvictionCause to RemovalCause

[uncle-lv]

In most caches(redis、caffeine and etc.), eviction means the entry is removed due to maxsize limit. But on_delete callback will be executed in all removal cases. EvictionCause can lead to a misunderstanding, RemovalCause should be a better name.

[coveralls]

coverage: 100.0%. remained the same when pulling 8a9cdca on uncle-lv:rename-EvictionCause into 51c88ba on dgilland:master.

[uncle-lv]

Another reason is expired_count evicted_count deleted_count will be three different figures in statistics. But EvictionCause includes all three cases, what can lead to a misunderstanding too.

[dgilland]

Just a minor nit to align the docstring of the class with the class rename.

[dgilland]

nit: Can replace "eviction" with "removal".

Suggested change

	An enum to represent the cause for the eviction of a cache entry.
	An enum to represent the cause for the removal of a cache entry.

[uncle-lv]

Updated usage.

Usage

set on_delete callback.

cache = Cache(on_delete=on_delete)

on_delete is a callable object.

Callable[[key: Hashable, value: Any, cause: RemovalCause],  None]

First parameter is the key of cache entry has been deleted.

Second is the value.

Third is the cause of cache entry removal.

RemovalCause is an enum.

class RemovalCause(Enum):
    DELETE = auto()
    SET = auto()
    EXPIRED = auto()
    FULL = auto()
    POPITEM = auto()

• DELETE: indicates that the cache entry was deleted by delete() or delete_many() explicitly.
• SET: indicates that the cache entry was replaced with a new value by set() or set_many().
• EXPIRED: indicates that the cache entry was removed because it expired.
• FULL: indicates that the cache entry was removed because cache has been full (reached the maximum size limit).
• POPITEM: indicates that the cache entry was deleted by popitem().

Trigger

The table shows methods will trigger on_delete.

cause	trigger
DELETE	The cache entry was removed explicitly by delete() or delete_many()
SET	The cache entry was replaced by set() or set_many()
POPITEM	The cache entry was deleted by popitem()
EXPIRED	Implicit. When the cache entry was removed because it expired
FULL	Implicit. The cache entry was removed because cache has reached the maximum size limit

⚠ clear() never triggers on_delete.