NAME
Class::Handle - Create objects that are handles to Classes
SYNOPSIS
# Create a class handle
use Class::Handle;
my $class = Class::Handle->new( 'Foo::Class' );
my $name = $class->name;
# UNIVERSAL type methods
$class->VERSION();
$class->isa( 'Foo:Bar' );
$class->can( 'blah' );
# Class::Inspector type methods
$class->installed();
$class->loaded();
$class->filename();
$class->resolved_filename();
$class->functions();
$class->function_refs();
$class->function_exists( 'function' );
$class->methods( 'public', 'full' );
$class->subclasses();
# Class::ISA type methods
$class->super_path();
$class->self_and_super_path();
$class->full_super_path();
# Loading and unloading
$class->load();
DESCRIPTION
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::ISA" and "Class::Inspector" for obtaining
information about a Class, and some additional task methods, such as
"load" to common tasks relating to classes.
UNIVERSAL API
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 "<Class::Handle-"VERSION>> is 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
print Foo::Bar->VERSION;
# Getting the version via Class::Handle
my $class = Class::Handle->new( 'Foo::Bar' );
print $class->VERSION;
This also applies to the "isa" and "can" methods.
METHODS
new $class
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
name
The c<name> method returns the name of the class as original specified
in the constructor.
VERSION
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.
isa $class
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 "UNIVERSAL::isa"
can $method
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.
installed
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
otherwise.
loaded
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", "Foo::Bar"
and "Foo::Buffy", the "loaded" method will return true for all of the
classes.
Returns true if the class is loaded, or false otherwise.
filename
Returns the base filename for a class. For example, for the class
"Foo::Bar", "loaded" would return "Foo/Bar.pm".
The "filename" method is platform neutral, it should always return the
filename in the correct format for your platform.
resolved_filename @extra_paths
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.
loaded_filename
If the class is loaded, returns the name of the file that it was
originally loaded from.
Returns false if the class is not loaded, or did not have its own file.
functions
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.
function_refs
Returns a list of references to all the functions in the classes
immediate namespace.
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.
function_exists $function
Checks to see if the function exists in the class. Note that this is as
a function, not as a method. To see if a method exists for a class, use
the "can" method in UNIVERSAL, and hence to every other class.
Returns true if the function exists, false if the function does not
exist, or "undef" on error, or if the class is not loaded.
methods @options
Attempts to find the methods available to the class. This includes
everything in the classes super path up to, but NOT including,
UNIVERSAL. Returns a reference to an array of the names of all the
available methods on success. Returns undef if the class is not loaded.
Any provided options are passed through, and alter the response in the
same way as for the options to "<Class::Inspector-"methods()>>, that is,
'public', 'private', 'full' and 'expanded', and combinations thereof.
subclasses
The "subclasses" method will search then entire namespace (and thus all
currently loaded classes) to find all of the subclasses of the class
handle.
The actual test will be done by calling "isa" on the class as a static
method. (i.e. "<My::Class-"isa($class)>>.
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 invalid.
super_path
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.
self_and_super_path
As above, but includes ourself at the beginning of the path. Directly
passes through to Class::ISA.
full_super_path
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 Class::ISA itself.
BUGS
No known bugs. Additional feature requests are being taken.
SUPPORT
Bugs should be reported via the CPAN bug tracking system
<http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Class-Handle>
For other inquiries, contact the author
AUTHOR
Adam Kennedy <adamk@cpan.org>, <http://ali.as/>
SEE ALSO
"UNIVERSAL", "Class::ISA", and "Class::Inspector", which provide most of
the functionality for this class.
COPYRIGHT
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.