bento_meta.entity

This module contains * Entity, the base class for metamodel objects, * the CollValue class to manage collection-valued attributes, and * the ArgError exception.

Module Contents

Classes

Entity	Base class for all metamodel objects.
CollValue	A UserDict for housing Entity collection attributes.

exception bento_meta.entity.ArgError

Bases: Exception

Exception for method argument errors

class bento_meta.entity.Entity(init=None)

Bases: object

Base class for all metamodel objects.

Entity contains all the magic for metamodel objects such as bento_meta.objects.Node and ‘bento_meta.object.Edge`. It will rarely be used directly. Entity redefines __setattr__ and __getattr__ to enable necessary bookkeeping for model versioning and graph database object mapping under the hood.

The Entity class also defines private and declared attributes that are common to all metamodel objects. It provides the machinery to manage private attributes separately from declared attributes, and to raise exceptions when attempts are made to access attributes that are not declared.

property dirty

Flag whether this instance has been changed since retrieval from the database Set to -1, ensure that the next time an attribute is accessed, the instance will retrieve itself from the database.

property versioned

Is this instance versioned?

property removed_entities

property object_map

property belongs

Dict that stores information on the owners (referents) of this instance in the model

pvt_attr = ['pvt', 'neoid', 'dirty', 'removed_entities', 'attspec', 'mapspec', 'belongs']

defaults = ()

attspec_

attspec

mapspec_

object_map

version_count

versioning_on = False

classmethod mapspec()

The object to database mapping specification. Is a class method, not a property.

classmethod versioning(on=None)

Get or set whether versioning is applied to object manipulations :param boolean on: True, apply versioning. False, do not.

classmethod set_version_count(ct)

Set the integer version counter. This will usually be accessed via a bento_meta.Model instance :param int ct: Set version counter to this value

classmethod default(propname)

Returns a default value for the property named, or None if no default defined.

get_by_id(id)

Get an object from the db with the id attribute (not the Neo4j id). Returns a new object. :param string id: value of id for desired object

clear_removed_entities()

set_with_dict(init)

set_with_node(init)

set_with_entity(ent)

__getattribute__(name)

Return getattr(self, name).

__getattr__(name)

__setattr__(name, value)

Implement setattr(self, name, value).

version_me()

_set_declared_attr(name, value)

__delattr__(name)

Implement delattr(self, name).

_check_init(init)

_check_value(att, value)

dup()

Duplicate the object, but not too deeply. Mainly for use of the versioning machinery.

delete()

Delete self from the database. If versioning is active, this will ‘deprecate’ the entity, but not actually remove it from the db

dget(refresh=False)

Update self from the database :param boolean refresh: if True, force a retrieval from db; if False, retrieve from cache; don’t disrupt changes already made

dput()

Put self to the database. This will set the neoid property if not yet set.

rm(force)

Delete self from the database. The object instance survives.

classmethod attr_doc()

Create a docstring for declared attributes on class as configured

class bento_meta.entity.CollValue(init=None, *, owner, owner_key)

Bases: collections.UserDict

A UserDict for housing Entity collection attributes. This class contains a hook for recording the Entity that owns the value that is being set. The value is marked as belonging to the containing object, not this collection object. It also protects against adding arbitrarily typed elements to the collection; it throws unless a value to set is an Entity. __setitem__ is instrumented for managing versioning.

Parameters:

• owner – Entity object of which this collection is an attribute

• owner_key – the attribute name of this collection on the owner

property owner

The entity instance of which this collection is an attribute

property owner_key

The attribute name of this collection on the owner

version_me()

__setitem__(name, value)

__getitem__(name)

__delitem__(name)