||User Contributed Perl Documentation
Class::Handle - Create objects that are handles to Classes
# Create a class handle
my $class = Class::Handle->new( 'Foo::Class' );
my $name = $class->name;
# UNIVERSAL type methods
$class->isa( 'Foo:Bar' );
$class->can( 'blah' );
# Class::Inspector type methods
$class->function_exists( 'function' );
$class->methods( 'public', 'full' );
# Class::ISA type methods
# Loading and unloading
Class related functionality in Perl is broken up into a variety of different
modules. Class::Handle attempts to provide a convenient object wrapper around
the various different types of functions that can be performed on a class.
Please note that this is an initial non-production quality
release, and should be used as such. Functionality and API are subject to
change without notice.
Currently, Class::Handle provies what is effectively a combined
API from "UNIVERSAL",
"Class::Inspector" for obtaining
information about a Class, and some additional task methods, such as
"load" to common tasks relating to
To ensure we maintain compliance with other classes that rely on methods
provided by "UNIVERSAL", Class::Handle acts
in the normal way when something like
called. That is, it returns the version of Class::Handle itself. When
"UNIVERSAL" methods are called on an
instantiation the method is changed to act on the class we have a handle to.
For example, the two following statements are equivalent.
# Getting the version directly
# Getting the version via Class::Handle
my $class = Class::Handle->new( 'Foo::Bar' );
This also applies to the "isa"
and "can" methods.
The "new" constructor will create a new handle
to a class or unknown existance or status. That is, it won't check that the
class actually exists at this time. It WILL however check to make sure that
your class name is legal.
Returns a new Class::Handle object on success
Returns undef if the class name is illegal
The c<name> method returns the name of the class as original specified in
Find the version for the class. Does not check that the class is loaded ( at
this time ).
Returns the version on success,
"undef" if the class does not defined a
$VERSION or the class is not loaded.
Checks to see if the class is a subclass of another class. Does not check that
the class is loaded ( at this time ).
Returns true/false as for
Checks to see if a particular method is defined for the class.
Returns a "CODE" ref to the
function is the method is available, or false if the class does not have
that method available.
Checks to see if a particular class is installed on the machine, or at least
that the class is available to perl. In this case, "class" really
means "module". This methods cannot detect a class that is not a
module. ( Has its own file ).
Returns true if the class is installed and available, or false
Checks to see if a class is loaded. In this case, "class" does NOT
mean "module". The "loaded" method
will return true for classes that do not have their own file.
For example, if a module "Foo"
contains the classes "Foo",
"loaded" method will return true for all
of the classes.
Returns true if the class is loaded, or false otherwise.
Returns the base filename for a class. For example, for the class
"loaded" would return
The "filename" method is
platform neutral, it should always return the filename in the correct format
for your platform.
The "resolved_filename" will attempt to find
the real file on your system that will be used when a class is loaded. If
additional paths are provided as argument, they will be tried first, before
the contents of the @INC array. If a file cannot be
found to match the class, returns false.
If the class is loaded, returns the name of the file that it was originally
Returns false if the class is not loaded, or did not have its own
Returns a list of the names of all the functions in the classes immediate
namespace. Note that this is not the METHODS of the class, just the functions.
Returns a reference to an array of the function names on success.
Returns undef on error or if the class is not loaded.
Returns a list of references to all the functions in the classes immediate
Returns a reference to an array of CODE refs of the functions on
success, or "undef" on error or if the
class is not loaded.
Checks to see if the function exists in the class. Note that this is as a
function, not as a method. To see if a method exists for a class, use the
"can" method in UNIVERSAL, and hence to
every other class.
Returns true if the function exists, false if the function does
not exist, or "undef" on error, or if the
class is not loaded.
Attempts to find the methods available to the class. This includes everything in
the classes super path up to, but NOT including, UNIVERSAL. Returns a
reference to an array of the names of all the available methods on success.
Returns undef if the class is not loaded.
Any provided options are passed through, and alter the response in
the same way as for the options to
that is, 'public', 'private', 'full' and 'expanded', and combinations
The "subclasses" method will search then
entire namespace (and thus all currently loaded classes) to find all of
the subclasses of the class handle.
The actual test will be done by calling
"isa" on the class as a static method.
Returns a reference to a list of the names of the loaded classes
that match the class provided, or false is none match, or
"undef" if the class name provided is
The "super_path" method is a straight pass
through to the "Class::ISA::super_path"
function. Returns an ordered list of class names, with no duplicates. The list
does NOT include the class itself, or the UNIVERSAL class.
As above, but includes ourself at the beginning of the path. Directly passes
through to Class::ISA.
The "full_super_path" method is an additional
method not in "Class::ISA". It returns as
for "super_path", except that it also
contains BOTH the class itself, and
"UNIVERSAL". This full list is more
technically accurate, but less commonly used, and as such isn't available from
No known bugs. Additional feature requests are being taken.
Bugs should be reported via the CPAN bug tracking system
For other inquiries, contact the author
Adam Kennedy <email@example.com>, <http://ali.as/>
"Class::Inspector", which provide most of
the functionality for this class.
Copyright (c) 2002 - 2006 Adam Kennedy.
This program is free software; you can redistribute it and/or
modify it under the same terms as Perl itself.
The full text of the license can be found in the LICENSE file
included with this module.
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