app/DB/baseorm.py

   1 import abc
   2
   3 class QueryException(Exception):
   4     pass
   5
   6 class OrmSubject(object, metaclass=abc.ABCMeta):
   7     @abc.abstractmethod
   8     def addObserver(self, ormObserver):
   9         pass
  10
  11     @abc.abstractmethod
  12     def removeObserver(self, ormObserver):
  13         pass
  14
  15     @abc.abstractmethod
  16     def notify(self, subject):
  17         pass
  18
  19 class Observer(object, metaclass=abc.ABCMeta):
  20     @abc.abstractmethod
  21     def update(self, subject):
  22         pass
  23
  24 class BaseOrm(OrmSubject):
  25
  26     def __init__(self):
  27         self.__observers = []
  28         self.__oldValues = {}
  29
  30     def addObserver(self, ormObserver):
  31         print("Added: {0}".format(ormObserver))
  32         self.__observers.append(ormObserver)
  33
  34     def removeObserver(self, ormObserver):
  35         self.__observers.remove(ormObserver)
  36
  37     def notify(self, object):
  38         for observer in self.__observers:
  39             observer.update(object)
  40
  41     @classmethod
  42     def query(cls, **kwargs):
  43         objects = []
  44         from app import db
  45         if kwargs:
  46             if hasattr(cls, '__tablename__'):
  47                 table = cls.__tablename__
  48             else:
  49                 table = cls.__name__
  50             o = db.query(table, **kwargs)
  51             if table.lower() == 'user':
  52                 for user in o:
  53                     objects.append(cls(user[1], user[2], user[3], user[4], user[0]))
  54             elif table.lower() == 'portfolio':
  55                 for portfolio in o:
  56                     user = db.query('user', id = portfolio[2])[0]
  57                     objects.append(cls(portfolio[1], user, portfolio[3], portfolio[4], portfolio[0]))
  58         else:
  59             raise QueryException("{0}: Missing at least one query parameter".format(cls))
  60         return objects
  61
  62     def commit(self):
  63         self.notify(self)
  64         self.__oldValues = {}
  65
  66     def rollback(self):
  67         for k, v in self.__oldValues.items():
  68             setattr(self, k, v)
  69         self.__oldValues = {}
  70
  71     @property
  72     def id(self):
  73         return self.__id
  74
  75     @id.setter
  76     def id(self, id):
  77         try:
  78             self.__oldValues['id'] = self.id
  79         except AttributeError:
  80             pass
  81         self.__id = id