1 files changed, 55 insertions, 0 deletions
diff --git a/azure/aria/aria-extension-cloudify/src/aria/aria/parser/presentation/source.py b/azure/aria/aria-extension-cloudify/src/aria/aria/parser/presentation/source.py
new file mode 100644
index 0000000..4bfb8e1
--- /dev/null
+++ b/azure/aria/aria-extension-cloudify/src/aria/aria/parser/presentation/source.py
@@ -0,0 +1,55 @@
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements.  See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.
+# The ASF licenses this file to You 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.
+
+
+from ...extension import parser
+
+from .exceptions import PresenterNotFoundError
+
+
+class PresenterSource(object):
+    """
+    Base class for ARIA presenter sources.
+
+    Presenter sources provide appropriate :class:`Presenter` classes for agnostic raw data.
+    """
+
+    def get_presenter(self, raw):  # pylint: disable=unused-argument,no-self-use
+        raise PresenterNotFoundError('presenter not found')
+
+
+class DefaultPresenterSource(PresenterSource):
+    """
+    The default ARIA presenter source.
+    """
+
+    def __init__(self, classes=None):
+        if classes is None:
+            classes = parser.presenter_class()
+        self.classes = classes
+
+    def get_presenter(self, raw):
+        for cls in self.classes:
+            if cls.can_present(raw):
+                return cls
+
+        if 'tosca_definitions_version' in raw:
+            if raw['tosca_definitions_version'] is None:
+                raise PresenterNotFoundError("'tosca_definitions_version' is not specified")
+            if not isinstance(raw['tosca_definitions_version'], basestring):
+                raise PresenterNotFoundError("'tosca_definitions_version' is not a string")
+            if not raw['tosca_definitions_version']:
+                raise PresenterNotFoundError("'tosca_definitions_version' is not specified")
+        return super(DefaultPresenterSource, self).get_presenter(raw)