- move annotation model and containers to package annotations

- implement AnnotationContainerFactory

annotations/container.py

@@ -0,0 +1,97 @@
+import os
+import fnmatch
+from core.exceptions import ImproperlyConfigured
+
+class AnnotationContainerFactory:
+    def __init__(self, containers):
+        """
+        Initialize the factory with the mappings between file pattern and
+        the container.
+
+        Parameters
+        ==========
+        containers: tuple of tuples (str, str/class)
+            The mapping between file pattern and container class responsible
+            for loading/saving.
+        """
+        self.containers_ = containers
+
+    def create(self, filename, *args, **kwargs):
+        """
+        Create a container for the filename.
+
+        Parameters
+        ==========
+        filename: str
+            Filename for which a matching container should be created.
+        *args, **kwargs:
+            Arguments passed to constructor of the container.
+        """
+        for pattern, container in self.containers_:
+            if fnmatch.fnmatch(filename, pattern):
+                return container(*args, **kwargs)
+        raise ImproperlyConfigured("No container registered for filename %s" % filename)
+
+class AnnotationContainer:
+    def __init__(self):
+        self.clear()
+
+    def filename(self):
+        return self.filename_
+
+    def clear(self):
+        self.annotations_ = []
+        self.filename_    = None
+
+    def load(self, filename):
+        """
+        Load the annotations.  Must be implemented in the subclass.
+        """
+        pass
+
+    def save(self, filename):
+        """
+        Save the annotations.  Must be implemented in the subclass.
+        """
+        pass
+
+    def annotations(self):
+        """
+        Returns the current annotations as python dictionary.
+        """
+        return self.annotations_
+
+    def loadImage(self, filename):
+        """
+        Load the image referenced to by the filename.  In the default
+        implementation this will try to load the image from a path
+        relative to the label files directory.
+        """
+        pass
+
+    def loadVideo(self, filename):
+        """
+        Load the video referenced to by the filename.  In the default
+        implementation this will try to load the video from a path
+        relative to the label files directory.
+        """
+        pass
+
+    def setAnnotations(self, annotations):
+        self.annotations_ = annotations
+
+    def numFiles(self):
+        return len(self.annotations_)
+
+    def numAnnotations(self):
+        if self.annotations_ is None:
+            return 0
+        num = 0
+        for file in self.annotations_:
+            if file['type'] == 'image':
+                num += len(file['annotations'])
+            elif file['type'] == video:
+                for frame in file['frames']:
+                    num += len(frame['annotations'])
+        return num
+