X-Git-Url: https://git.madduck.net/etc/taskwarrior.git/blobdiff_plain/5ba0e1105517f8b0e22b0bcf5c79f40a0fb644d9..d66fcc9dcef74ab7cafee718cbb9fa78fec92d03:/tasklib/filters.py

diff --git a/tasklib/filters.py b/tasklib/filters.py
index 1899d1d..0a74c3c 100644
--- a/tasklib/filters.py
+++ b/tasklib/filters.py
@@ -1,7 +1,36 @@
-from tasklib.serializing import SerializingObject
+import abc
+import six
+from .serializing import SerializingObject
 
 
-class TaskFilter(SerializingObject):
+class TaskFilter(object):
+    """
+    Abstract base class that defines interface of a TaskFilter.
+    """
+
+    @abc.abstractmethod
+    def add_filter(self, arg):
+        """
+        Processes an non-keyword filter.
+        """
+        pass
+
+    @abc.abstractmethod
+    def add_filter_param(self, key, value):
+        """
+        Processes a keyword filter.
+        """
+        pass
+
+    @abc.abstractmethod
+    def clone(self):
+        """
+        Returns a new deep copy of itself.
+        """
+        pass
+
+
+class TaskWarriorFilter(TaskFilter, SerializingObject):
     """
     A set of parameters to filter the task list with.
     """