# ___________________________________________________________________________ # # Pyomo: Python Optimization Modeling Objects # Copyright 2017 National Technology and Engineering Solutions of Sandia, LLC # Under the terms of Contract DE-NA0003525 with National Technology and # Engineering Solutions of Sandia, LLC, the U.S. Government retains certain # rights in this software. # This software is distributed under the 3-clause BSD License. # ___________________________________________________________________________ # # This module was originally developed as part of the PyUtilib project # Copyright (c) 2008 Sandia Corporation. # This software is distributed under the BSD License. # Under the terms of Contract DE-AC04-94AL85000 with Sandia Corporation, # the U.S. Government retains certain rights in this software. # ___________________________________________________________________________ class Factory(object): """ A class that is used to define a factory for objects. Factory objects may be cached for future use. """ def __init__(self, description=None): self._description = description self._cls = {} self._doc = {} def __call__(self, name, **kwds): if 'exception' in kwds: exception = kwds['exception'] del kwds['exception'] else: exception = False name = str(name) if not name in self._cls: if not exception: return None if self._description is None: raise ValueError("Unknown factory object type: '%s'" % name) raise ValueError("Unknown %s: '%s'" % (self._description, name)) return self._cls[name](**kwds) def __iter__(self): for name in self._cls: yield name def __contains__(self, name): return str(name) in self._cls def get_class(self, name): return self._cls[name] def doc(self, name): return self._doc[name] def unregister(self, name): name = str(name) if name in self._cls: del self._cls[name] del self._doc[name] def register(self, name, doc=None): def fn(cls): self._cls[name] = cls self._doc[name] = doc return cls return fn