--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/app/soc/logic/models/ranker_root.py	Wed Mar 04 17:04:25 2009 +0000
@@ -0,0 +1,80 @@
+#!/usr/bin/python2.5
+#
+# Copyright 2009 the Melange authors.
+#
+# 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.
+
+"""RankerRoot (Model) query functions.
+"""
+
+__authors__ = [
+  '"Lennard de Rijk" <ljvderijk@gmail.com>',
+  ]
+
+from google.appengine.api import datastore
+
+from ranklist.ranker import Ranker
+
+from soc.logic.models import base
+
+import soc.models.ranker_root
+
+
+class Logic(base.Logic):
+  """Logic methods for the RankerRoot model.
+  """
+
+  def __init__(self, model=soc.models.ranker_root.RankerRoot, 
+               base_model=None, scope_logic=None):
+    """Defines the name, key_name and model for this entity.
+    """
+
+    super(Logic, self).__init__(model=model, base_model=base_model,
+                                scope_logic=scope_logic)
+
+  def create(self, name, scope, scores, branching_factor):
+    """Creates a new RankerRoot with a new Ranker.
+
+    Args:
+      name: the Link ID of the ranker root
+      scope: the entity owning the ranker
+      score_range: A list showing the range of valid scores, in the form:
+          [most_significant_score_min, most_significant_score_max,
+          less_significant_score_min, less_significant_score_max, ...]
+          Ranges are [inclusive, exclusive)
+      branching_factor: The branching factor of the tree.  The number of
+          datastore Gets is Theta(1/log(branching_factor)), and the amount of data
+          returned by each Get is Theta(branching_factor). 
+
+    """
+    ranker = Ranker.Create(scores, branching_factor)
+
+    fields = {'link_id': name,
+        'scope': scope,
+        'scope_path': scope.key().name(),
+        'root': ranker.rootkey}
+
+    key_name = self.getKeyNameFromFields(fields)
+    self.updateOrCreateFromKeyName(fields, key_name)
+
+  def getRootFromEntity(self, entity):
+    """Returns a Ranker object created from a RankerRoot entity.
+
+    Args:
+      entity: A RankerRoot entity which the root should be retrieved of
+    """
+
+    return Ranker(datastore.Get(entity.key())['root'])
+
+
+logic = Logic()