Class::meta class introspection
# Assuming MyApp::Thingy was generated by Class::Meta.
my $class = MyApp::Thingy->my_class;
my $thingy = MyApp::Thingy->new;
print "Examining object of class ", $class->package, $/;
print "\nConstructors:\n";
for my $ctor ($class->constructors) {
print " o ", $ctor->name, $/;
}
print "\nAttributes:\n";
for my $attr ($class->attributes) {
print " o ", $attr->name, " => ", $attr->get($thingy) $/;
}
print "\nMethods:\n";
for my $meth ($class->methods) {
print " o ", $meth->name, $/;
}
Object of this class describe classes created by Class::Meta. They contain everything you need to know about a class to be able to put objects of that class to good use. In addition to retrieving meta data about the class itself, you can retrieve objects that describe the constructors, attributes, and methods of the class. See \*(C`Class::Meta|Class::Meta\*(C' for a fuller description of the utility of the Class::Meta suite of modules.
Class::Meta::Class objects are created by Class::Meta; they are never instantiated directly in client code. To access the class object for a Class::Meta-generated class, simply call its \*(C`my_class()\*(C' method.
At this point, those attributes tend to be database-specific. Once other types of data stores are added (\s-1XML\s0, \s-1LDAP\s0, etc.), other attributes may be added to allow their schemas to be built, as well.
new
A protected method for constructing a Class::Meta::Class object. Do not call this method directly; Call the \*(C`new()\*(C' constructor on a Class::Meta object, instead. A Class::Meta::Class object will be constructed by default, and can always be retrieved via the \*(C`my_class()\*(C' method of the class for which it was constructed.
package
my $pkg = $class->package;
Returns the name of the package that the Class::Meta::Class object describes.
key
my $key = $class->key;
Returns the key name that uniquely identifies the class across the application. The key name may simply be the same as the package name.
name
my $name = $class->name;
Returns the name of the the class. This should generally be a descriptive name, rather than a package name.
desc
my $desc = $class->desc;
Returns a description of the class.
abstract
my $abstract = $class->abstract;
Returns true if the class is an abstract class, and false if it is not.
default_type
my $default_type = $class->default_type;
The data type used for attributes of the class that were added with no explicit types.
trusted
my @trusted = $class->trusted; my $trusted = $class->trusted;
In an array context, returns a list of class names that this class trusts. Returns the same list in an array reference in a scalar context.
is_a
if ($class->is_a('MyApp::Base')) { print "All your base are belong to us\n"; }
This method returns true if the object or package name passed as an argument is an instance of the class described by the Class::Meta::Class object or one of its subclasses. Functionally equivalent to \*(C`$class->package->isa($pkg)\*(C', but more efficient.
constructors
my @constructors = $class->constructors; my $ctor = $class->constructors($ctor_name); @constructors = $class->constructors(@ctor_names);
Provides access to the Class::Meta::Constructor objects that describe the constructors for the class. When called with no arguments, it returns all of the constructor objects. When called with a single argument, it returns the constructor object for the constructor with the specified name. When called with a list of arguments, returns all of the constructor objects with the specified names.
attributes
my @attributes = $class->attributes; my $attr = $class->attributes($attr_name); @attributes = $class->attributes(@attr_names);
Provides access to the Class::Meta::Attribute objects that describe the attributes for the class. When called with no arguments, it returns all of the attribute objects. When called with a single argument, it returns the attribute object for the attribute with the specified name. When called with a list of arguments, returns all of the attribute objects with the specified names.
methods
my @methods = $class->methods; my $meth = $class->methods($meth_name); @methods = $class->methods(@meth_names);
Provides access to the Class::Meta::Method objects that describe the methods for the class. When called with no arguments, it returns all of the method objects. When called with a single argument, it returns the method object for the method with the specified name. When called with a list of arguments, returns all of the method objects with the specified names.
parents
my @parents = $class->parents;
Returns a list of Class::Meta::Class objects representing all of the Class::Meta-built parent classes of a class.
handle_error
$class->handle_error($error)
Handles Class::Meta-related errors using either the error handler specified when the Class::Meta::Class object was created or the default error handler at the time the Class::Meta::Class object was created.
build
$class->build($classes);
This is a protected method, designed to be called only by the Class::Meta class or a subclass of Class::Meta. It copies the attribute, constructor, and method objects from all of the parent classes of the class object so that they will be readily available from the \*(C`attributes()\*(C', \*(C`constructors()\*(C', and \*(C`methods()\*(C' methods. Its sole argument is a reference to the hash of all Class::Meta::Class objects (keyed off their package names) stored by Class::Meta.
Although you should never call this method directly, subclasses of Class::Meta::Class may need to override its behavior.
This module is stored in an open GitHub repository <http://github.com/theory/class-meta/>. Feel free to fork and contribute!
Please file bug reports via GitHub Issues <http://github.com/theory/class-meta/issues/> or by sending mail to [email protected] <mailto:[email protected]>.
David E. Wheeler <[email protected]>
Other classes of interest within the Class::Meta distribution include:
Copyright (c) 2002-2011, David E. Wheeler. Some Rights Reserved.
This module is free software; you can redistribute it and/or modify it under the same terms as Perl itself.