Provided by: libclass-mixinfactory-perl_0.92-5_all
NAME
Class::MixinFactory - Class Factory with Selection of Mixins
SYNOPSIS
package MyClass; use Class::MixinFactory -hasafactory; sub new { ... } sub foo { return "Foo Bar" } package MyClass::Logging; sub foo { warn "Calling foo"; (shift)->NEXT('foo', @_) } package MyClass::UpperCase; sub foo { uc( (shift)->NEXT('foo', @_) ) } package main; my $class = MyClass->class( 'Logging', 'UpperCase' ); print $class->new()->foo(); # Calls MyClass::Logging::foo, MyClass::UpperCase::foo, MyClass::foo
DESCRIPTION
This distribution facilitates the run-time generation of classes which inherit from a base class and some optional selection of mixin classes. A factory is provided to generate the mixed classes with multiple inheritance. A NEXT method allows method redispatch up the inheritance chain.
USAGE
The Class::MixinFactory package is just a facade that loads the necessary classes and provides a few import options for compile-time convenience. Factory Interface To generate an object with some combination of mixins, you first pass the names of the mixin classes to a class factory which will generate a mixed class. (Or return the name of the already generated class, if there has been a previous request with the same combination of mixins.) You can add a factory method to your base class, create a separate factory object, or inherit to produce a factory class. Factory Method To add a factory method to a base class, inherit from the Class::MixinFactory::HasAFactory class, or use the "-hasafactory" import option: package MyClass; use Class::MixinFactory -hasafactory; package main; my $class = MyClass->class( 'Logging', 'UpperCase' ); print $class->new()->foo(); Factory Class To create a new class which will act as a factory for another base class, inherit from the Class::MixinFactory::Factory class, or use the "-isafactory" import option: package MyClass::Factory; use Class::MixinFactory -isafactory; MyClass::Factory->base_class( "MyClass" ); package main; my $class = MyClass::Factory->class( 'Logging', 'UpperCase' ); print $class->new()->foo(); Factory Object To create an object which will act as a factory, create a Class::MixinFactory::Factory instance by calling the new() method: use Class::MixinFactory; my $factory = Class::MixinFactory->new(); $factory->base_class( "MyClass" ); my $class = $factory->class( 'Logging', 'UpperCase' ); print $class->new()->foo(); Inheriting from a Mixed Class Inheriting with a Factory Method or Factory Object A subclass can inherit from a mixed class: package MyClass::CustomWidget; @ISA = MyClass->class( 'Logging', 'UpperCase' ); sub foo { local $_ = (shift)->NEXT('foo', @_); tr[a-z][z-a]; $_ } package main; print MyClass::CustomWidget->new()->foo(); Inheriting with a Factory Class A subclass can use a factory class to define its own inheritance: package MyClass::CustomWidget; use Class::MixinFactory -isasubclass, MyClass::Factory => 'Logging', 'UpperCase'; sub foo { local $_ = (shift)->NEXT('foo', @_); tr[a-z][z-a]; $_ } package main; print MyClass::CustomWidget->new()->foo(); Configuring a Factory Factories support methods that control which classes they will use. The base class will be inherited from by all mixed classes. $factory->base_class( "HelloWorld" ); The mixin prefix is prepended to the mixin names passed to the class() method. Mixin names that contain a "::" are assumed to be fully qualified and are not changed. If empty, the base_class is used. $factory->mixin_prefix( 'HelloFeature' ); The mixed prefix is at the start of all generated class names. If empty, the base_class is used, or the factory's class name. $factory->mixed_prefix( 'HelloClass' ); Writing a Mixin Class Writing a mixin class is almost the same as writing a subclass, except where methods need to redispatch to the base-class implementation. (The SUPER::method syntax will only search for classes that the mixin itself inherits from; to search back up the inheritance tree and explore other branches, another redispatch mechanism is needed.) A method named NEXT is provided to continue the search through to the next class which provides a given method. The order in which mixins are stacked is significant, so the caller should understand how their behaviors interact. (See Class::MixinFactory::NEXT.)
SEE ALSO
For distribution, installation, support, copyright and license information, see Class::MixinFactory::ReadMe.