cached_getter

lsst.utils.classes.cached_getter(func: Callable[[_S], _R]) → Callable[[_S], _R]

Decorate a method to cache the result.

Only works on methods that take only self as an argument, and returns the cached result on subsequent calls.

Parameters

funcCallable

Method from which the result should be cached.

Returns

Callable

Decorated method.

Notes

This is intended primarily as a stopgap for Python 3.8’s more sophisticated functools.cached_property, but it is also explicitly compatible with the immutable decorator, which may not be true of cached_property.

cached_getter guarantees that the cached value will be stored in an attribute named _cached_{name-of-decorated-function}. Classes that use cached_getter are responsible for guaranteeing that this name is not otherwise used, and is included if __slots__ is defined.