kivitendo/SL/DB/Helper/Presenter.pm @ 43749680
| 972b8771 | Sven Schöling | package SL::DB::Helper::Presenter;
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use strict;
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sub new {
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# lightweight: 0: class, 1: object
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bless [ $_[1], $_[2] ], $_[0];
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}
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sub AUTOLOAD {
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our $AUTOLOAD;
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my ($self, @args) = @_;
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my $method = $AUTOLOAD;
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$method =~ s/.*:://;
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return if $method eq 'DESTROY';
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| 43c3e3bc | Moritz Bunkus | eval "require $self->[0]";
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| cef8c551 | Sven Schöling | splice @args, -1, 1, %{ $args[-1] } if @args && (ref($args[-1]) eq 'HASH');
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| 0e5e3501 | Sven Schöling | if (my $sub = $self->[0]->can($method)) {
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return $sub->($self->[1], @args);
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}
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| 972b8771 | Sven Schöling | }
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| 43c3e3bc | Moritz Bunkus | sub can {
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my ($self, $method) = @_;
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eval "require $self->[0]";
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$self->[0]->can($method);
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}
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| 972b8771 | Sven Schöling | 1;
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__END__
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=encoding utf-8
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=head1 NAME
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SL::DB::Helper::Presenter - proxy class to allow models to access presenters
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=head1 SYNOPSIS
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| 1918cfae | Geoffrey Richardson | # assuming SL::Presenter::Part exists
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| 972b8771 | Sven Schöling | # and contains a sub link_to($class, $object) {}
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SL::DB::Part->new(%args)->presenter->link_to
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=head1 DESCRIPTION
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| 1918cfae | Geoffrey Richardson | When coding controllers one often encounters objects that are not crucial to
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the current task, but must be presented in some form to the user. Instead of
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| 972b8771 | Sven Schöling | recreating that all the time the C<SL::Presenter> namepace was introduced to
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hold such code.
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Unfortunately the Presenter code is designed to be stateless and thus acts _on_
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objects, but can't be instanced or wrapped. The early band-aid to that was to
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export all sub-presenter calls into the main presenter namespace. Fixing it
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| 1918cfae | Geoffrey Richardson | would have meant accessing presenter functions like this:
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| 972b8771 | Sven Schöling | |||
SL::Presenter::Object->method($object, %additional_args)
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| 1918cfae | Geoffrey Richardson | which is extremely inconvenient.
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| 972b8771 | Sven Schöling | |||
This glue code allows C<SL::DB::Object> instances to access routines in their
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presenter without additional boilerplate. C<SL::DB::Object> contains a
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C<presenter> call for all objects, which will return an instance of this proxy
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class. All calls on this will then be forwarded to the appropriate presenter.
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=head1 INTERNAL STRUCTURE
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| 1918cfae | Geoffrey Richardson | The created proxy objects are lightweight blessed arrayrefs instead of the
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usual blessed hashrefs. They only store two elements:
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| 972b8771 | Sven Schöling | |||
=over 4
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=item * The presenter class
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=item * The invocing object
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=back
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Further delegation is done with C<AUTOLOAD>.
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=head1 BUGS
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None yet :)
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=head1 AUTHOR
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Sven Schöling E<lt>s.schoeling@linet-services.deE<gt>
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=cut
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