"""
data_provider
-------------
The :code:`data_provider` module provides a base class for data provider
classes. This class provides utility function for the composition of data providers
as well as the overriding of get functions.
"""
import numpy as np
################################################################################
# Data provider classes
################################################################################
[docs]class DataProviderBase:
"""
The :code:`DataProviderBase` implements generic functionality for
- The overriding of get methods with attributes
- Composition of data providers
When a data provider inherits from :code:`DataProviderBase`, the values
returned from a :code:`get_<attribute>` can be overriding simply setting
the attribute with the name :code:`<attribute>` of the object.
The DataProviderBase also allows composing data provider by adding sub-
providers to a data provider object. If a simulation queries a get_method
from the data provider that the data provider doesn't provide, the query
is forwarded to the subproviders in the order they were added. The get
method from the first that provides such a method is returned.
"""
def __init__(self):
self.owner = None
self.subproviders = []
[docs] def add(self, subprovider):
"""
Add a subprovider to the data provider.
Arguments:
subprovider: The subprovider to add. Must inherit
from :code:`DataProviderBase`.
Raises:
Exception: If :code: `subprovider` argument doesn´t inherit
from :code:`DataProviderBase`.
"""
if not isinstance(subprovider, DataProviderBase):
raise Exception("Subprovider objects must inherit from DataProviderBase.")
subprovider.owner = self
self.subproviders += [subprovider]
def __getattribute__(self, name):
if not name[:4] == "get_":
return object.__getattribute__(self, name)
else:
attribute_name = name[4:]
#
# Get name from self with priority for the attribute.
#
try:
x = object.__getattribute__(self, attribute_name)
def wrapper(*args, **kwargs):
return x
return wrapper
except:
pass
try:
return object.__getattribute__(self, name)
except:
pass
#
# Get name from first list provider which has any of the
# has either a fitting attribute or get_method.
#
for p in self.subproviders:
try:
return getattr(p, name)
except:
pass
raise AttributeError("'{0}' object has no attribute '{1}'."\
.format(type(self).__name__, name))
[docs]class CombinedProvider(DataProviderBase):
"""
The :code:`CombinedProvider` allows the combination of multiple data
providers. If a get method is requested from the data provider it is
forwarded to the combined providers. The lookup is performed in the
same order as the providers are provided to the constructor and the
first hit is returned.
"""
def __init__(self, *args):
self.super()
self.providers = list(*args)
[docs] def add(self, provider):
"""
Add a provider to the combined data provider.
Arguments:
provider: The data provider to add. Must inherit
from :code:`DataProviderBase`.
Raises:
Exception: If :code: `provider` argument doesn´t inherit
from :code:`DataProviderBase`.
"""
if not isinstance(subprovider, DataProviderBase):
raise Exception("Data provider to add objects must inherit from "
"DataProviderBase.")
subprovider.owner = self
self.providers += [provider]
def __getattribute__(self, name):
if not name[:4] == "get_":
return object.__getattribute__(self, name)
else:
#
# Get name from first list provider which has any of the
# has either a fitting attribute or get_method.
#
for p in self.providers:
try:
return getattr(p, name)
except:
pass
raise AttributeError("'{0}' object has no attribute '{1}'."\
.format(type(self).__name__, name))