Provided by: libur-perl_0.410-1_all 
NAME
UR::Object::Type - a meta-class for any class or primitive type
SYNOPSIS
use UR;
class MyClass {
is => ['ParentClass1', 'ParentClass2'],
id_by => [
id_prop1 => { is => 'Integer' },
id_prop2 => { is => 'String' },
],
has => [
property_a => { is => 'String' }
property_b => { is => 'Integer', is_optional => 1 },
],
};
my $meta = MyClass->__meta__;
my @parent_class_metas = $meta->parents();
# 2 meta objects, see UR::Object::Property
my @property_meta = $meta->properties();
# N properties (4, +1 from UR::Object, +? from ParentClass1 and ParentClass2)
$meta->is_abstract;
$meta->...
DESCRIPTION
UR::Object::Type implements the class behind the central metadata in the UR class
framework. It contains methods for introspection and manipulation of related class data.
A UR::Object::Type object describes UR::Object, and also every subclass of UR::Object.
INHERITANCE
Each sub-class of UR::Object has a single UR::Object::Type object describing the class.
The UR::Object class itself also has a UR::Object::Type object describing the base class
of the system.
In addition to describing UR::Object an each of its subclasses, UR::Object::Type is
_itself_ a subclass of UR::Object. This means that the same query APIs used for regular
objects can be used for meta objects.
/-----------------------\
V |
UR::Object -> has-meta -> UR::Object::Type --> has-meta >--/
A |
\ /
\-----<- is-a <-------/
Further, new classes which generate a new UR::Object::Type, also generate a private
subclass for the meta-class. This means that each new class can have private meta
methods, (ala Ruby).
This also means that extensions to a meta-class, apply to the meta-class of its
derivatives.
Regular Meta-Class
Entity Singleton
------- ----------
Greyhound has-meta -> Greyhound::Type
| |
V V
is-a is-a
| |
V V
Dog has-meta -> Dog::Type
| |
V V
is-a is-a
| |
V V
Animal has-meta -> Animal::Type
| |
V V
is-a is-a
| | /-----------------\
V V V |
UR::Object has-meta -> UR::Object::Type has-meta -/
A is-a
| |
\________________________/
CONSTRUCTORS
"class"
class MyClass1 {};
class MyClass2 { is => 'MyClass1' };
class MyClass3 {
is => ['Parent1','Parent2'],
is_abstract => 1,
is_transient => 1,
has => [ qw/p1 p2 p3/ ],
doc => 'woo hoo!'
};
The primary constructor is not a method on this class at all. UR catches "class
SOMENAME { ... }" and calls define() with the parameters.
define
my $class_obj = UR::Object::Type->define(
class_name => 'MyClass',
...
);
Register a class with the system. The given class_name must be unique within the
application. As a side effect, a new Perl namespace will be created for the class's
name, and methods will be injected into that namespace for any of the class
properties. Other types of metadata objects will get created to manage the properties
and relationships to other classes. See the UR::Object::Type::Initializer
documentation for more information about the parameters "define()" accepts.
create
my $class_obj = UR::Object::Type->create(
class_name => 'Namespace::MyClass',
...
);
Create a brand new class within an already existing UR namespace. "create()" takes
all the same parameters as "define()". Another side effect of create is that when the
application commits its Context, a new Perl module will be created to implement the
class, complete with a class definition.
Applications will not normally use create().
PROPERTIES
Each property has a method of the same name
External API
class_name
$name = $class_obj->class_name
The full name of the class. This is symmetrical with $class_obj = $name->__meta__.
properties
@all = $class_obj->properties();
@some = $class_obj->properties(
'is => ['Text','Number']
'doc like' => '%important%',
'property_name like' => 'someprefix_%',
);
Access the related property meta-objects for all properties of this class. It
includes the properties of any parent classes which are inherited by this class.
See UR::Object::Property for details.
id_properties
@all_id = $class_obj->id_properties();
@some = $class_obj->properties(
'is => ['Text','Number']
'doc like' => '%important%',
'property_name like' => 'someprefix_%',
);
Like properties(), but only returns ID property metadata.
property
$property_meta = $class_obj->property('someproperty');
The singular version of the above. A single argument, as usual, is treated as the
remainder of the ID, and will select a property by name.
property_names
@names = $class_obj->property_names;
Returns a list of all properties belonging to the class, directly or through
inheritance.
namespace
$namespace_name = $class_obj->namespace
Returns the name of the class's UR namespace.
doc
$doc = $class_obj->doc
A place to put general class-specific notes.
data_source_id
$ds_id = $class_obj->data_source_id
The name of the external data source behind this class. Classes without data sources
cannot be saved and exist only during the life of the application. data_source_id
will resolve to an UR::DataSource id.
table_name
$table_name = $class_object->table_name
For classes with data sources, this is the name of the table within that data source.
This is usually a table in a relational database.
At a basic level, it is a storage directive interpreted by the data_source, and may or
may not related to a storage table at that level.
is_abstract
$bool = $class_obj->is_abstract
A flag indicating if this is an abstract class. Abstract classes cannot have
instances, but can be inherited by other classes.
is_final
$bool = $class_obj->is_final
A flag indicating if this class cannot have subclasses.
is_singleton
$bool = $class_obj->is_singleton
A flag indicating whether this is a singleton class. If true, the class will inherit
from UR::Singleton.
is_transactional
$bool = $class_obj->is_transactional
A flag indicating whether changes to this class's instances will be tracked. Non-
transactional objecs do not change when an in-memory transaction rolls back.
It is similar to the is_transient meta-property, which does the same for an individual
property.
Internal API
These methods return data about how this class relates to other classes.
namespace_meta
$ns_meta = $class_obj->namespace_meta
Returns the UR::Namespace object with the class's namespace name.
parent_class_names
@names = $class_obj->parent_class_names
Returns a list of the immediate parent classes.
parent_class_metas
@class_objs = $class_obj->parent_class_metas
Returns a list of the class objects (UR::Object::Type instances) of the immediate
parent classes
ancestry_class_names
@names = $class_obj->ancestry_class_names
Returns a list of all the class names this class inherits from, directly or
indirectly. This list may have duplicate names if there is multiple inheritance in
the family tree.
ancestry_class_metas
@class_objs = $class_obj->ancestry_class_metas
Returns a list of the class objects for each inherited class.
direct_property_names
@names = $class_obj->direct_property_names
Returns a list of the property names defined within this class. This list will not
include the names of any properties inherited from parent classes unless they have
been overridden.
direct_property_metas
@property_objs = $class_obj->direct_property_metas
Returns a list of the UR::Object::Property objects for each direct property name.
ancestry_property_names
@names = $class_obj->ancestry_property_names
Returns a list of property names of the parent classes and their inheritance
heirarchy. The list may include duplicates if a property is overridden somewhere in
the heirarchy.
ancestry_property_metas
@property_objs = $class_obj->ancestry_property_metas;
Returns a list of the UR::Object::Property objects for each ancestry property name.
all_property_names
Returns a list of property names of the given class and its inheritance heirarchy.
The list may include duplicates if a property is overridden somewhere in the
heirarchy.
all_property_metas
@property_objs = $class_obj->all_property_metas;
Returns a list of the UR::Object::Property objects for each name returned by
all_property_names.
direct_id_property_names
@names = $class_obj->direct_id_property_names
Returns a list of the property names designated as "id" properties in the class
definition.
direct_id_property_metas
@property_objs = $class_obj->direct_id_property_metas
Returns a list of the UR::Object::Property objects for each id property name.
ancestry_id_property_names
ancestry_id_property_metas
all_id_property_names
all_id_property_metas
@names = $class_obj->ancestry_id_property_names;
@property_objs = $class_obj->ancestry_id_property_metas;
@names = $class_obj->all_id_property_names;
@property_objs = $class_obj->all_id_property_metas;
Returns the property names or UR::Object::Property objects for either the parent
classes and their inheritance heirarchy, or for the given class and all of its
inheritance heirarchy. The lists may include duplicates if properties are overridden
somewhere in the heirarchy.
unique_property_set_hashref
$constraints = $class_obj->unique_property_set_hashref
Return a hashref describing the unique constraints on the given class. The keys of
$constraint are constraint names, and the values are listrefs of property names that
make up the unique constraint.
add_unique_constraint
$class_obj->add_unique_constraint($constraint_name, @property_name_list)
Add a unique constraint to the given class. It is an exception if the given
$constraint_name already exists as a constraint on this class or its parent classes.
remove_unique_constraint
$class_obj->remove_unique_constraint($constraint_name)
Remove a unique constraint from the given class. It is an exception if the given
constraint name does not exist.
ancestry_table_names
all_table_names
@names = $class_obj->ancestry_table_names
Returns a list of table names in the class's inheritance heirarchy.
direct_column_names
Returns a list of column names for each direct property meta. Classes with data
sources and table names will have properties with column names.
direct_id_column_names
Returns a list of ID column names for each direct property meta.
direct_columnless_property_names
direct_columnless_property_metas
ancestry_columnless_property_names
ancestry_columnless_property_metas
all_columnless_property_names
all_columnless_property_metas
Return lists of property meta objects and their names for properties that have no
column name.
METHODS
property_meta_for_name
$property_obj = $class_obj->property_meta_for_name($property_name);
Return the UR::Object::Property object in the class's inheritance hierarchy with the
given name. If the property name has been overridden somewhere in the hierarchy, then
it will return the property object most specific to the class.
id_property_sorter
$subref = $class_obj->id_property_sorter;
@sorted_objs = sort $subref @unsorted_objs;
Returns a subroutine reference that can be used to sort object instances of the class.
The subref is able to handle classes with multiple ID properties, and mixes of numeric
and non-numeric data and data types.
autogenerate_new_object_id
This method is called whenever new objects of the given class are created through
"ClassName->create()", and not all of their ID properties were specified.
UR::Object::Type has an implementation used by default, but other classes can override
this if they need special handling.
SEE ALSO
UR::Object::Property