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−#!/usr/bin/python2.5
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−#
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−# Copyright 2009 the Melange authors.
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−#
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−# Licensed under the Apache License, Version 2.0 (the "License");
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−# you may not use this file except in compliance with the License.
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−# You may obtain a copy of the License at
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−#
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−#   http://www.apache.org/licenses/LICENSE-2.0
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−#
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−# Unless required by applicable law or agreed to in writing, software
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−# distributed under the License is distributed on an "AS IS" BASIS,
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−# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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−# See the License for the specific language governing permissions and
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−# limitations under the License.
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−
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−"""RankerRoot (Model) query functions.
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−"""
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−
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−__authors__ = [
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−  '"Lennard de Rijk" <ljvderijk@gmail.com>',
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−  ]
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−
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−from google.appengine.api import datastore
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−
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−from ranklist.ranker import Ranker
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−
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−from soc.logic.models import base
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−
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−import soc.models.ranker_root
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−
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−
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−class Logic(base.Logic):
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−  """Logic methods for the RankerRoot model.
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−  """
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−
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−  def __init__(self, model=soc.models.ranker_root.RankerRoot, 
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−               base_model=None, scope_logic=None):
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−    """Defines the name, key_name and model for this entity.
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−    """
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−
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−    super(Logic, self).__init__(model=model, base_model=base_model,
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−                                scope_logic=scope_logic)
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−
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−  def create(self, name, scope, scores, branching_factor):
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−    """Creates a new RankerRoot with a new Ranker.
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−
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−    Args:
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−      name: the Link ID of the ranker root
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−      scope: the entity owning the ranker
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−      score_range: A list showing the range of valid scores, in the form:
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−          [most_significant_score_min, most_significant_score_max,
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−          less_significant_score_min, less_significant_score_max, ...]
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−          Ranges are [inclusive, exclusive)
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−      branching_factor: The branching factor of the tree.  The number of
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−          datastore Gets is Theta(1/log(branching_factor)), and the amount of data
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−          returned by each Get is Theta(branching_factor). 
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−
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−    """
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−    ranker = Ranker.Create(scores, branching_factor)
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−
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−    fields = {'link_id': name,
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−        'scope': scope,
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−        'scope_path': scope.key().id_or_name(),
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−        'root': ranker.rootkey}
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−
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−    key_name = self.getKeyNameFromFields(fields)
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−    self.updateOrCreateFromKeyName(fields, key_name)
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−
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−  def getRootFromEntity(self, entity):
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−    """Returns a Ranker object created from a RankerRoot entity.
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−
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−    Args:
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−      entity: A RankerRoot entity which the root should be retrieved of
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−    """
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−
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−    return Ranker(datastore.Get(entity.key())['root'])
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−
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−
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−logic = Logic()