Value class inheritanced by StringValue, IntValue FloatValue

1 files changed, 43 insertions, 9 deletions

diff --git a/ebus/web/model.py b/ebus/web/model.py
index e9fc04c..04b15ed 100644
--- a/ebus/web/model.py
+++ b/ebus/web/model.py
@@ -19,8 +19,7 @@ class Sensor(ModelBase):
     def __repr__(self):
         return "<Sensor('%s','%s','%s')>" % (self.id, self.name, self.description)
 
-
-
+# http://www.sqlalchemy.org/docs/05/reference/ext/declarative.html#inheritance-configuration
 class Value(ModelBase):
     __tablename__ = 'value'
 
@@ -29,17 +28,52 @@ class Value(ModelBase):
     sensor_id = Column(Integer, ForeignKey("sensor.id"))
     sensor = relationship(Sensor, backref=backref('values', order_by=timestamp))
 
-    value_float = Column(Float(precision=4))
-    value_int = Column(Integer)
-    value_string = Column(String)
+    discriminator = Column('type', String(50))
+    __mapper_args__ = {'polymorphic_on': discriminator}
 
-    def __init__(self, sensor, value_float=None, value_int=None, value_string=None, timestamp=datetime.now()):
+    def __init__(self, sensor, timestamp=datetime.now()):
         self.timestamp = timestamp
         self.sensor  = sensor
-        self.value_float = value_float
-        self.value_int = value_int
-        self.value_string = value_string
 
     def __repr__(self):
         return "<Value('%s','%s','%s','%s'>" % (self.id, self.sensor, self.value, self.timestamp)
 
+    def value(self):
+        raise NotImplementedException()
+
+class ValueInt(Value):
+    __mapper_args__ = {'polymorphic_identity': 'value'}
+    value_float = Column(Float(precision=4))
+    
+    def __init__(self, sensor, value, timestamp=datetime.now()):
+        Value.__init__(self, sensor, timestamp)
+        self.value_float = value
+
+    def value(self):
+        return self.value_float
+
+class ValueInt(Value):
+    __mapper_args__ = {'polymorphic_identity': 'value'}
+    value_int = Column(Integer)
+
+    def __init__(self, sensor, value, timestamp=datetime.now()):
+        Value.__init__(self, sensor, timestamp)
+        self.value_int = value
+
+    def value(self):
+        return self.value_int
+
+class ValueString(Value):
+    __mapper_args__ = {'polymorphic_identity': 'value'}
+    value_string = Column(String)
+
+    def __init__(self, sensor, value, timestamp=datetime.now()):
+        Value.__init__(self, sensor, timestamp)
+        self.value_int = value
+
+    def value(self):
+        return self.value_string
+
+
+
+