Source Code for Module madrona.manipulators.models

 1  from django.db import models 
 2  from django.contrib.gis.db import models 
 3   
 4   
 5 -class BaseManipulatorGeometryManager(models.GeoManager): 
 6      """Returns the currently active data layer (determined by the active attribute). 
 7      """ 
 8 -    def current(self): 
 9          return self.get(active=True) 
10   
11 -class BaseManipulatorGeometry(models.Model): 
12      """Abstract Model in which an inheriting subclass can be used for storing a data layer used by a Manipulator 
13   
14          ======================  ============================================== 
15          Attribute               Description 
16          ======================  ============================================== 
17          ``creation_date``       When the layer was created. Is not changed on 
18                                  updates. 
19   
20          ``active``              Whether this layer represents the current  
21                                  data layer. If set to true and and another 
22                                  layer is active, that old layer will be  
23                                  deactivated. 
24          ======================  ============================================== 
25      """     
26      creation_date = models.DateTimeField(auto_now=True)  
27   
28      active = models.BooleanField(default=True, help_text=""" 
29          Checking here indicates that this layer list should be the one used in 
30          the application. Copies of other layer lists are retained in the 
31          system so you can go back to an old version if necessary. 
32      """) 
33   
34      objects = BaseManipulatorGeometryManager() 
35   
36 -    def save(self, *args, **kwargs): 
37          super(BaseManipulatorGeometry, self).save(*args, **kwargs) 
38          if self.active and self.__class__.objects.filter(active=True).count() > 1: 
39              # Ensure that any previously active layer is deactivated -- There can be only one! 
40              self.__class__.objects.filter(active=True).exclude(pk=self.pk).update(active=False) 
41   
42 -    class Meta: 
43          abstract = True 
44