NAME

UR::Singleton - Abstract class for implementing singleton objects

SYNOPSIS

            

              
              
package MyApp::SomeClass;
use UR;
class MyApp::SomeClass {
    is => 'UR::Singleton',
    has => [
        foo => { is => 'Number' },
    ]
};
$obj = MyApp::SomeClass->get();
$obj->foo(1);
            
          

DESCRIPTION

This class provides the infrastructure for singleton classes. Singletons are classes of which there can only be one instance, and that instance's ID is the class name.

If a class inherits from UR::Singleton, it overrides the default implementation of get() and is_loaded() in UR::Object with code that fabricates an appropriate object the first time it's needed.

Singletons are most often used as one of the parent classes for data sources within a Namespace. This makes it convienent to refer to them using only their name, as in a class definition.

METHODS

_singleton_object

            

              
              
$obj = Class::Name->_singleton_object;
$obj = $obj->_singleton_object;
            
          

Returns the object instance whether it is called as a class or object method.

_singleton_class_name

            

              
              
$class_name = Class::Name->_singleton_class_name;
$class_name = $obj->_singleton_class_name;
            
          

Returns the class name whether it is called as a class or object method.

SEE ALSO

UR::Object