NAME
Object::Stash - provides a Catalyst-like "stash" method for your class
SYNOPSIS
{
package MyClass;
use Object::New;
use Object::Stash 'data';
}
use feature 'say';
use Data::Printer qw(p);
my $obj = MyClass->new;
p $obj->data; # an empty hashref
$obj->data(foo => 1, bar => 2); # sets values in the 'data' stash
$obj->data({foo => 1, bar => 2}); # same
p $obj->data; # hashref with keys 'foo', 'bar'
say $obj->data->{foo}; # says '1'
# Retrieve multiple values
my @values = $obj->data(['foo', 'bar']);
say $values[0]; # says '1'
say $values[1]; # says '2'
# Or in scalar context
my $values = $obj->data(['foo', 'bar']);
say $values->[0]; # says '1'
say $values->[1]; # says '2'
DESCRIPTION
The Catalyst context object has a method called stash, that provides a
hashref for storing arbitrary data associated with the object. This is
arguably a little hackish - the proper solution might be to create a
slot for each piece of information you wish to store, with appropriate
accessor methods. But often hackish will do.
(And there are non-hackish ways of using Object::Stash. Take a look at
Web::Magic which uses a private stash - named with a leading underscore
- and provides public methods for accessing various things stored inside
it.)
Object::Stash sets up one or more stash methods for your class. How
these methods are named depends on how Object::Stash is imported.
Object::Stash is a role, like Object::New or Object::ID. This means you
import it, but don't inherit from it.
Default method name
package MyClass;
use Object::Stash;
Creates a single method for MyClass objects. The method is called
"stash".
Custom method name
package MyClass;
use Object::Stash 'data';
Creates a single method for MyClass objects. The method is called
"data".
Multiple methods
package MyClass;
use Object::Stash qw/important trivial/;
Creates two stashes for MyClass objects, called "important" and
"trivial". Adding data to one stash will not affect the other stash. You
could alternatively write:
package MyClass;
use Object::Stash 'important'
use Object::Stash 'trivial';
Adding stashes to other classes
package MyClass;
use Object::Stash -package => 'YourClass', 'my_stash';
Creates a stash called "my_stash" for YourClass objects.
Utility Functions
"Object::Stash->is_stash( $coderef )"
Returns true if the method is a stash. For example:
my $method = MyClass->can('trivial');
if (Object::Stash->is_stash($method))
{
$method->(foo => 1, bar => 2);
}
Can also be called as "Object::Stash::is_stash($coderef)".
Stash Storage
Stashes are stored "inside-out", meaning that they will work not only
with objects which are blessed hashrefs, but also with any other type of
object internals. Dumping your object with Data::Dumper or similar will
not display the contents of the stashes. (A future release of this
module may introduce other storage options, but the current inside-out
storage is likely to remain the default.)
Thanks to Hash::FieldHash, an object's stashes *should* get
automatically garbage collected once the object itself is destroyed,
unless you've maintained your own references to the stashes.
Stash Objects
While stashes are usually hashrefs, there is also an option to make
stashes themselves blessed objects. It's best to illustrate this with an
example
{
package MyClass;
use Object::New;
use Object::Stash 'data', -type => 'object';
}
# All this stuff from SYNOPSIS still works...
use feature 'say';
use Data::Printer qw(p);
my $obj = MyClass->new;
p $obj->data; # an empty hashref
$obj->data(foo => 1, bar => 2); # sets values in the 'data' stash
$obj->data({foo => 1, bar => 2}); # same
say $obj->data->{foo}; # says '1'
my @values = $obj->data(['foo', 'bar']);
say $values[0]; # says '1'
say $values[1]; # says '2'
my $values = $obj->data(['foo', 'bar']);
say $values->[0]; # says '1'
say $values->[1]; # says '2'
# But now you can retrieve data using accessor methods...
say $obj->data->foo; # says '1'
# The accessors work as not just getters, but setters...
$obj->data->foo(99);
# The accessors can be treated as lvalues...
$obj->data->foo = 100;
$obj->data->foo++;
# Cool, huh?
say $obj->data->{foo}; # says '101'
# In case you were wondering...
say ref $obj->data; # says 'Object::Stash::data'
BUGS
Please report any bugs to
<http://rt.cpan.org/Dist/Display.html?Queue=Object-Stash>.
SEE ALSO
Object::New, Object::ID.
AUTHOR
Toby Inkster <tobyink@cpan.org>.
COPYRIGHT AND LICENCE
This software is copyright (c) 2011 by Toby Inkster.
This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.
DISCLAIMER OF WARRANTIES
THIS PACKAGE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED
WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.