Class::Simple::Readonly::Cached - cache messages to an object


Version 0.09


A sub-class of Class::Simple which caches calls to read the status of an object that are otherwise expensive.

It is up to the caller to maintain the cache if the object comes out of sync with the cache, for example by changing its state.

You can use this class to create a caching layer to an object of any class that works on objects which doesn't change its state based on input:

    use Class::Simple::Readonly::Cached;

    my $obj = Class::Simple->new();
    $obj = Class::Simple::Readonly::Cached->new(object => $obj, cache => {});
    my $val = $obj->val();
    print "$val\n";     # Prints "foo"
    #... set $obj to be some other class which will take an argument 'a',
    #   with a value 'b'
    $val = $obj->val(a => 'b'); # You



Creates a Class::Simple::Readonly::Cached object.

It takes one mandatory parameter: cache, which is either an object which understands clear(), get() and set() calls, such as an CHI object; or is a reference to a hash where the return values are to be stored.

It takes one optional argument: object, which is an object which is taken to be the object to be cached. If not given, an object of the class Class::Simple is instantiated and that is used.

    use Gedcom;

    my %hash;
    my $person = Gedcom::Person->new();
    ... # Set up some data
    my $object = Class::Simple::Readonly::Cached(object => $person, cache => \%hash);
    my $father1 = $object->father();    # Will call gedcom->father() to get the person's father
    my $father2 = $object->father();    # Will retrieve the father from the cache without calling person->father()

Takes one optional argument: quiet, if you attempt to cache an object that is already cached, rather than create another copy you receive a warning and the previous cached copy is returned. The 'quiet' option, when non-zero, silences the warning.


Return the encapsulated object


Returns the state of the object

    print Data::Dumper->new([$obj->state()]->Dump();


Nigel Horne, <njh at>


Doesn't work with Memoize.

Please report any bugs or feature requests to I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.


Class::Simple, CHI


You can find documentation for this module with the perldoc command.

    perldoc Class::Simple::Readonly::Cached

You can also look for information at:


Author Nigel Horne: Copyright (C) 2019-2023 Nigel Horne

Usage is subject to licence terms. The licence terms of this software are as follows: Personal single user, single computer use: GPL2 All other users (including Commercial, Charity, Educational, Government) must apply in writing for a licence for use from Nigel Horne at the above e-mail.