- column_property(), composite_property(), and relation() now

accept a single or list of AttributeExtensions using the
"extension" keyword argument.
- Added a Validator AttributeExtension, as well as a
@validates decorator which is used in a similar fashion
as @reconstructor, and marks a method as validating
one or more mapped attributes.
- removed validate_attributes example, the new methodology replaces it

2 files changed, 2 insertions, 118 deletions

diff --git a/examples/custom_attributes/listen_for_events.py b/examples/custom_attributes/listen_for_events.py
index e980e61ed..c028e0fb4 100644
--- a/examples/custom_attributes/listen_for_events.py
+++ b/examples/custom_attributes/listen_for_events.py
@@ -1,5 +1,6 @@
 """
-Illustrates how to use AttributeExtension to listen for change events.
+Illustrates how to use AttributeExtension to listen for change events 
+across the board.
 
 """
 
diff --git a/examples/custom_attributes/validate_attributes.py b/examples/custom_attributes/validate_attributes.py
deleted file mode 100644
index 63b2529fd..000000000
--- a/examples/custom_attributes/validate_attributes.py
+++ /dev/null
@@ -1,117 +0,0 @@
-"""
-Illustrates how to use AttributeExtension to create attribute validators.
-
-"""
-
-from sqlalchemy.orm.interfaces import AttributeExtension, InstrumentationManager
-
-class InstallValidators(InstrumentationManager):
-    """Searches a class for methods with a '_validates' attribute and assembles Validators."""
-    
-    def __init__(self, cls):
-        self.validators = {}
-        for k in dir(cls):
-            item = getattr(cls, k)
-            if hasattr(item, '_validates'):
-                self.validators[item._validates] = item
-                
-    def instrument_attribute(self, class_, key, inst):
-        """Add an event listener to an InstrumentedAttribute."""
-        
-        if key in self.validators:
-            inst.impl.extensions.insert(0, Validator(key, self.validators[key]))
-        return super(InstallValidators, self).instrument_attribute(class_, key, inst)
-        
-class Validator(AttributeExtension):
-    """Validates an attribute, given the key and a validation function."""
-    
-    def __init__(self, key, validator):
-        self.key = key
-        self.validator = validator
-    
-    def append(self, state, value, initiator):
-        return self.validator(state.obj(), value)
-
-    def set(self, state, value, oldvalue, initiator):
-        return self.validator(state.obj(), value)
-
-def validates(key):
-    """Mark a method as validating a named attribute."""
-    
-    def wrap(fn):
-        fn._validates = key
-        return fn
-    return wrap
-
-if __name__ == '__main__':
-
-    from sqlalchemy import *
-    from sqlalchemy.orm import *
-    from sqlalchemy.ext.declarative import declarative_base
-    import datetime
-    
-    Base = declarative_base(engine=create_engine('sqlite://', echo=True))
-    Base.__sa_instrumentation_manager__ = InstallValidators
-
-    class MyMappedClass(Base):
-        __tablename__ = "mytable"
-    
-        id = Column(Integer, primary_key=True)
-        date = Column(Date)
-        related_id = Column(Integer, ForeignKey("related.id"))
-        related = relation("Related", backref="mapped")
-
-        @validates('date')
-        def check_date(self, value):
-            if isinstance(value, str):
-                m, d, y = [int(x) for x in value.split('/')]
-                return datetime.date(y, m, d)
-            else:
-                assert isinstance(value, datetime.date)
-                return value
-        
-        @validates('related')
-        def check_related(self, value):
-            assert value.data == 'r1'
-            return value
-            
-        def __str__(self):
-            return "MyMappedClass(date=%r)" % self.date
-            
-    class Related(Base):
-        __tablename__ = "related"
-
-        id = Column(Integer, primary_key=True)
-        data = Column(String(50))
-
-        def __str__(self):
-            return "Related(data=%r)" % self.data
-    
-    Base.metadata.create_all()
-    session = sessionmaker()()
-    
-    r1 = Related(data='r1')
-    r2 = Related(data='r2')
-    m1 = MyMappedClass(date='5/2/2005', related=r1)
-    m2 = MyMappedClass(date=datetime.date(2008, 10, 15))
-    r1.mapped.append(m2)
-
-    try:
-        m1.date = "this is not a date"
-    except:
-        pass
-    assert m1.date == datetime.date(2005, 5, 2)
-    
-    try:
-        m2.related = r2
-    except:
-        pass
-    assert m2.related is r1
-    
-    session.add(m1)
-    session.commit()
-    assert session.query(MyMappedClass.date).order_by(MyMappedClass.date).all() == [
-        (datetime.date(2005, 5, 2),),
-        (datetime.date(2008, 10, 15),)
-    ]
-    
\ No newline at end of file