LSST Applications  21.0.0-172-gfb10e10a+18fedfabac,22.0.0+297cba6710,22.0.0+80564b0ff1,22.0.0+8d77f4f51a,22.0.0+a28f4c53b1,22.0.0+dcf3732eb2,22.0.1-1-g7d6de66+2a20fdde0d,22.0.1-1-g8e32f31+297cba6710,22.0.1-1-geca5380+7fa3b7d9b6,22.0.1-12-g44dc1dc+2a20fdde0d,22.0.1-15-g6a90155+515f58c32b,22.0.1-16-g9282f48+790f5f2caa,22.0.1-2-g92698f7+dcf3732eb2,22.0.1-2-ga9b0f51+7fa3b7d9b6,22.0.1-2-gd1925c9+bf4f0e694f,22.0.1-24-g1ad7a390+a9625a72a8,22.0.1-25-g5bf6245+3ad8ecd50b,22.0.1-25-gb120d7b+8b5510f75f,22.0.1-27-g97737f7+2a20fdde0d,22.0.1-32-gf62ce7b1+aa4237961e,22.0.1-4-g0b3f228+2a20fdde0d,22.0.1-4-g243d05b+871c1b8305,22.0.1-4-g3a563be+32dcf1063f,22.0.1-4-g44f2e3d+9e4ab0f4fa,22.0.1-42-gca6935d93+ba5e5ca3eb,22.0.1-5-g15c806e+85460ae5f3,22.0.1-5-g58711c4+611d128589,22.0.1-5-g75bb458+99c117b92f,22.0.1-6-g1c63a23+7fa3b7d9b6,22.0.1-6-g50866e6+84ff5a128b,22.0.1-6-g8d3140d+720564cf76,22.0.1-6-gd805d02+cc5644f571,22.0.1-8-ge5750ce+85460ae5f3,master-g6e05de7fdc+babf819c66,master-g99da0e417a+8d77f4f51a,w.2021.48
LSST Data Management Base Package
Public Member Functions | List of all members
lsst.ctrl.pool.pool.SingletonMeta Class Reference

Metaclass to produce a singleton. More...

Inheritance diagram for lsst.ctrl.pool.pool.SingletonMeta:
lsst.ctrl.pool.pool.Debugger lsst.ctrl.pool.pool.PoolNode lsst.ctrl.pool.pool.PoolMaster lsst.ctrl.pool.pool.PoolSlave

Public Member Functions

def __init__ (cls, name, bases, dict_)
 
def __call__ (cls, *args, **kwargs)
 

Detailed Description

Metaclass to produce a singleton.

Doing a singleton mixin without a metaclass (via __new__) is
annoying because the user has to name his __init__ something else
(otherwise it's called every time, which undoes any changes).
Using this metaclass, the class's __init__ is called exactly once.

Because this is a metaclass, note that:
* "self" here is the class
* "__init__" is making the class (it's like the body of the
  class definition).
* "__call__" is making an instance of the class (it's like
  "__new__" in the class).

Definition at line 367 of file pool.py.

Constructor & Destructor Documentation

◆ __init__()

def lsst.ctrl.pool.pool.SingletonMeta.__init__ (   cls,
  name,
  bases,
  dict_ 
)

Definition at line 383 of file pool.py.

383  def __init__(cls, name, bases, dict_):
384  super(SingletonMeta, cls).__init__(name, bases, dict_)
385  cls._instance = None
386 

Member Function Documentation

◆ __call__()

def lsst.ctrl.pool.pool.SingletonMeta.__call__ (   cls,
args,
**  kwargs 
)

Definition at line 387 of file pool.py.

387  def __call__(cls, *args, **kwargs):
388  if cls._instance is None:
389  cls._instance = super(SingletonMeta, cls).__call__(*args, **kwargs)
390  return cls._instance
391 
392 

The documentation for this class was generated from the following file: