diff --git a/IPython/core/component.py b/IPython/core/component.py
index 2be6db6..d2659d8 100644
--- a/IPython/core/component.py
+++ b/IPython/core/component.py
@@ -23,9 +23,9 @@ Authors:
from weakref import WeakValueDictionary
+from IPython.utils.ipstruct import Struct
from IPython.utils.traitlets import (
- HasTraitlets, TraitletError, MetaHasTraitlets,
- Int, Float, Str, Bool, Unicode
+ HasTraitlets, TraitletError, MetaHasTraitlets, Instance, This
)
@@ -34,10 +34,6 @@ from IPython.utils.traitlets import (
#-----------------------------------------------------------------------------
-class Config(object):
- pass
-
-
class MetaComponentTracker(type):
"""A metaclass that tracks instances of Components and its subclasses."""
@@ -47,9 +43,9 @@ class MetaComponentTracker(type):
cls.__numcreated = 0
def __call__(cls, *args, **kw):
- """Called when class is called (instantiated)!!!
+ """Called when *class* is called (instantiated)!!!
- Then a Component or subclass is instantiated, this is called and
+ When a Component or subclass is instantiated, this is called and
the instance is saved in a WeakValueDictionary for tracking.
"""
@@ -60,32 +56,34 @@ class MetaComponentTracker(type):
c.__instance_refs[c.__numcreated] = instance
return instance
- def get_instances(cls):
- """Get all instances of cls and its subclasses."""
- return cls.__instance_refs.values()
+ def get_instances(cls, name=None, klass=None, root=None):
+ """Get all instances of cls and its subclasses.
- def get_instances_by_name(cls, name):
- """Get all instances of cls and its subclasses by name."""
- return [i for i in cls.get_instances() if i.name == name]
-
- def get_instances_by_subclass(cls, thisclass):
- """Get all instances of cls that are instances of thisclass.
-
- This includes all instances of subclasses of thisclass.
+ Parameters
+ ----------
+ name : str
+ Limit to components with this name.
+ klass : class
+ Limit to components having isinstance(component, klass)
+ root : Component or subclass
+ Limit to components having this root.
"""
- return [i for i in cls.get_instances() if isinstance(i, thisclass)]
-
- def get_instances_by_class(cls, thisclass):
- """Get all instances of cls that are instances of thisclass.
-
- This exclused instances of thisclass subclasses.
+ instances = cls.__instance_refs.values()
+ if name is not None:
+ instances = [i for i in instances if i.name == name]
+ if klass is not None:
+ instances = [i for i in instances if isinstance(i, klass)]
+ if root is not None:
+ instances = [i for i in instances if i.root == root]
+ return instances
+
+ def get_instances_by_condition(cls, call, name=None, klass=None, root=None):
+ """Get all instances of cls, i such that call(i)==True.
+
+ This also takes the ``name``, ``klass`` and ``root`` arguments of
+ :meth:`get_instance`
"""
-
- return [i for i in cls.get_instances() if type(i) is thisclass]
-
- def get_instances_by_condition(cls, call):
- """Get all instances of cls, i such that call(i)==True."""
- return [i for i in cls.get_instances() if call(i)]
+ return [i for i in cls.get_instances(name,klass,root) if call(i)]
class ComponentNameGenerator(object):
@@ -117,7 +115,10 @@ class Component(HasTraitlets):
__metaclass__ = MetaComponent
- config = Config()
+ # Traitlets are fun!
+ config = Instance(Struct)
+ parent = This(allow_none=True)
+ root = This(allow_none=True)
def __init__(self, parent, name=None, config=None):
"""Create a component given a parent.
@@ -140,11 +141,13 @@ class Component(HasTraitlets):
to this argument. We might think about changing this behavior.
"""
super(Component, self).__init__()
+ self._children = []
if name is None:
- self._name = ComponentNameGenerator()
+ self.name = ComponentNameGenerator()
else:
- self._name = name
- self.parent = parent # this uses the property and handles None
+ self.name = name
+ self.root = self # This is the default, it is set when parent is set
+ self.parent = parent
if config is not None:
self.config = config
else:
@@ -152,33 +155,35 @@ class Component(HasTraitlets):
self.config = self.parent.config
#-------------------------------------------------------------------------
- # Properties
+ # Static traitlet notifiations
#-------------------------------------------------------------------------
- def _set_name(self, name):
- # This should use the ComponentNameGenerator to test for uniqueness
- self._name = name
-
- def _get_name(self):
- return self._name
+ def _parent_changed(self, name, old, new):
+ if old is not None:
+ old._remove_child(self)
+ if new is not None:
+ new._add_child(self)
- name = property(_get_name, _set_name)
-
- def _set_parent(self, parent):
- if parent is None:
- self._parent = None
- self._root = self
+ if new is None:
+ self.root = self
else:
- assert isinstance(parent, Component), 'parent must be a component'
- self._parent = parent
- self._root = parent.root
-
- def _get_parent(self):
- return self._parent
-
- parent = property(_get_parent, _set_parent)
+ self.root = new.root
@property
- def root(self):
- return self._root
-
+ def children(self):
+ """A list of all my child components."""
+ return self._children
+
+ def _remove_child(self, child):
+ """A private method for removing children componenets."""
+ if child in self._children:
+ index = self._children.index(child)
+ del self._children[index]
+
+ def _add_child(self, child):
+ """A private method for adding children componenets."""
+ if child not in self._children:
+ self._children.append(child)
+
+ def __repr__(self):
+ return "<Component('%s')>" % self.name
\ No newline at end of file
diff --git a/IPython/utils/tests/test_traitlets.py b/IPython/utils/tests/test_traitlets.py
index f9de690..1ca8f1a 100644
--- a/IPython/utils/tests/test_traitlets.py
+++ b/IPython/utils/tests/test_traitlets.py
@@ -31,7 +31,7 @@ from unittest import TestCase
from IPython.utils.traitlets import (
HasTraitlets, MetaHasTraitlets, TraitletType, Any,
Int, Long, Float, Complex, Str, Unicode, Bool, TraitletError,
- Undefined, Type, Instance
+ Undefined, Type, Instance, This
)
@@ -440,6 +440,44 @@ class TestInstance(TestCase):
b = B()
self.assertRaises(TraitletError, getattr, b, 'inst')
+
+class TestThis(TestCase):
+
+ def test_this_class(self):
+ class Foo(HasTraitlets):
+ this = This
+
+ f = Foo()
+ self.assertEquals(f.this, None)
+ g = Foo()
+ f.this = g
+ self.assertEquals(f.this, g)
+ self.assertRaises(TraitletError, setattr, f, 'this', 10)
+
+ def test_this_inst(self):
+ class Foo(HasTraitlets):
+ this = This()
+
+ f = Foo()
+ f.this = Foo()
+ self.assert_(isinstance(f.this, Foo))
+
+ def test_allow_none(self):
+ class Foo(HasTraitlets):
+ this = This(allow_none=False)
+
+ f = Foo()
+ g = Foo()
+ f.this = g
+ self.assertEquals(f.this, g)
+
+ f = Foo()
+ self.assertRaises(TraitletError, getattr, f, 'this')
+
+ f = Foo()
+ self.assertRaises(TraitletError, setattr, f, 'this', None)
+
+
class TraitletTestBase(TestCase):
"""A best testing class for basic traitlet types."""
diff --git a/IPython/utils/traitlets.py b/IPython/utils/traitlets.py
index 07c2929..0dcccab 100644
--- a/IPython/utils/traitlets.py
+++ b/IPython/utils/traitlets.py
@@ -167,19 +167,24 @@ class TraitletType(object):
dv = self.default_value
return dv
- def __get__(self, obj, cls=None):
+ def __get__(self, obj, cls=None, skipset=False):
"""Get the value of the traitlet by self.name for the instance.
-
+
The creation of default values is deferred until this is called the
first time. This is done so instances of the parent HasTraitlets
will have their own default value instances.
+
+ A default value is not validated until it is requested. Thus, if
+ you use an invalid default value, but never request it, you are fine.
"""
if obj is None:
return self
else:
if not obj._traitlet_values.has_key(self.name):
dv = self.get_default_value()
- self.__set__(obj, dv, first=True)
+ # Call __set__ with first=True so we don't get a recursion
+ if not skipset:
+ self.__set__(obj, dv, first=True)
return dv
else:
return obj._traitlet_values[self.name]
@@ -187,7 +192,8 @@ class TraitletType(object):
def __set__(self, obj, value, first=False):
new_value = self._validate(obj, value)
if not first:
- old_value = self.__get__(obj)
+ # Call __get__ with skipset=True so we don't get a recursion
+ old_value = self.__get__(obj, skipset=True)
if old_value != new_value:
obj._traitlet_values[self.name] = new_value
obj._notify_traitlet(self.name, old_value, new_value)
@@ -659,6 +665,40 @@ class Instance(BaseClassResolver):
return dv
+class This(TraitletType):
+ """A traitlet for instances of the class containing this trait."""
+
+ info_text = 'an instance of the same type as the receiver'
+
+ def __init__(self, default_value=None, allow_none=True, **metadata):
+ if default_value is not None:
+ raise TraitletError("The default value of 'This' can only be None.")
+ super(This, self).__init__(default_value, **metadata)
+ self._allow_none = allow_none
+ if allow_none:
+ self.info_text = self.info_text + ' or None'
+
+ def validate(self, obj, value):
+ if value is None:
+ if self._allow_none:
+ return value
+ self.validate_failed(obj, value)
+
+ if isinstance(value, obj.__class__):
+ return value
+ else:
+ self.validate_failed(obj, value)
+
+ def validate_failed (self, obj, value):
+ kind = type(value)
+ if kind is InstanceType:
+ msg = 'class %s' % value.__class__.__name__
+ else:
+ msg = '%s (i.e. %s)' % ( str( kind )[1:-1], repr( value ) )
+
+ self.error(obj, msg)
+
+
#-----------------------------------------------------------------------------
# Basic TraitletTypes implementations/subclasses
#-----------------------------------------------------------------------------