add component manager

dygraph/cvlibs/manager.py

+# -*- encoding: utf-8 -*-
+# Copyright (c) 2020 PaddlePaddle Authors. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import collections
+import inspect
+
+
+class ComponentManager:
+    """
+    Implement a manager class to add the new component properly.
+    For example:
+        >>> model_manager = ComponentManager()
+        >>> class AlexNet: ...
+        >>> class ResNet: ...
+        >>> model_manager.add_component(AlexNet)
+        >>> model_manager.add_component(ResNet)
+        or pass a sequence alliteratively:
+        >>> model_manager.add_component([AlexNet, ResNet])
+        >>> print(model_manager.components)
+    output: {'AlexNet': <class '__main__.AlexNet'>, 'ResNet': <class '__main__.ResNet'>}
+
+    Or a easier way, using it as a Python decorator, while just add it above the class declaration.
+        >>> model_manager = ComponentManager()
+        >>> @model_manager.add_component
+        >>> class AlexNet: ...
+        >>> @model_manager.add_component
+        >>> class ResNet: ...
+        >>> print(model_manager.components)
+    output: {'AlexNet': <class '__main__.AlexNet'>, 'ResNet': <class '__main__.ResNet'>}
+    """
+
+    def __init__(self):
+        self._components_dict = dict()
+
+    @property
+    def components(self):
+        return self._components_dict
+
+    def _add_single_component(self, component):
+        """
+        Add a single component into the corresponding manager
+
+        :param component (class): a new component
+        :return: None
+        """
+
+        # only support a class type
+        if not inspect.isclass(component):
+            raise TypeError("Expect class type, but received {}".format(type(component)))
+
+        # obtain the internal name of the component
+        component_name = component.__name__
+
+        # check whether the component was added already
+        if component_name in self._components_dict.keys():
+            raise KeyError("{} exists already!".format(component_name))
+        else:
+            # take the internal name of the component as its key
+            self._components_dict[component_name] = component
+
+    def add_component(self, components):
+        """
+        Add component(s) into the corresponding manager
+
+        :param components (class | list | tuple): support three types of components
+        :return: None
+        """
+
+        # check whether the type is a sequence
+        if isinstance(components, collections.Sequence):
+            for component in components:
+                self._add_single_component(component)
+        else:
+            component = components
+            self._add_single_component(component)
+
+    def __len__(self):
+        return len(self._components_dict)
+
+    def __str__(self):
+        print_str = "{}({})".format(self.__class__.__name__, self._components_dict)
+        return print_str
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