rebased "Introduction of ItemSource interface" patch

cellxgene_gateway/items/item.py

@@ -0,0 +1,41 @@
+# Copyright 2019 Novartis Institutes for BioMedical Research Inc. 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.
+
+from abc import ABC, abstractmethod
+from enum import Enum
+from typing import List
+
+
+class ItemType(Enum):
+    annotation = "annotation"
+    h5ad = "h5ad"
+
+
+class Item(ABC):
+    def __init__(self, name: str, type: ItemType, annotations: List["Item"] = None):
+        self.name = name
+        self.type = type
+        self.annotations = annotations
+
+    @property
+    @abstractmethod
+    def descriptor(self):
+        raise Exception('"descriptor" not implemented')
+
+
+class ItemTree:
+    def __init__(
+        self,
+        descriptor: str,
+        items: List[Item] = None,
+        branches: List["ItemTree"] = None,
+    ):
+        self.descriptor = descriptor
+        self.items = items
+        self.branches = branches