X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FMooseX%2FStorage%2FEngine%2FTrait%2FOnlyWhenBuilt.pm;fp=lib%2FMooseX%2FStorage%2FEngine%2FTrait%2FOnlyWhenBuilt.pm;h=427dfb4795ecb84dea457d82aa9659cb0a218f2a;hb=511f9c4baa29713783b2cebdb69a441ffe2190a3;hp=461c980f0d0f61720af4784e2c05707e176019c2;hpb=ec72518379c644ab85126ee0391773ee7028665c;p=gitmo%2FMooseX-Storage.git

diff --git a/lib/MooseX/Storage/Engine/Trait/OnlyWhenBuilt.pm b/lib/MooseX/Storage/Engine/Trait/OnlyWhenBuilt.pm
index 461c980..427dfb4 100644
--- a/lib/MooseX/Storage/Engine/Trait/OnlyWhenBuilt.pm
+++ b/lib/MooseX/Storage/Engine/Trait/OnlyWhenBuilt.pm
@@ -3,7 +3,7 @@ use Moose::Role;
 
 # we should
 # only serialize the attribute if it's already built. So, go ahead
-# and check if the attribute has a predicate. If so, check if it's 
+# and check if the attribute has a predicate. If so, check if it's
 # set  and then go ahead and look it up.
 around 'collapse_attribute' => sub {
     my ($orig, $self, $attr, @args) = @_;
@@ -18,3 +18,76 @@ around 'collapse_attribute' => sub {
 
 1;
 
+__END__
+
+=pod
+
+=head1 NAME
+
+MooseX::Storage::Engine::Trait::OnlyWhenBuilt - An engine trait to bypass serialization
+
+=head1 SYNOPSIS
+
+    {   package Point;
+        use Moose;
+        use MooseX::Storage;
+
+        with Storage( traits => [qw|OnlyWhenBuilt|] );
+
+        has 'x' => (is => 'rw', lazy_build => 1 );
+        has 'y' => (is => 'rw', lazy_build => 1 );
+        has 'z' => (is => 'rw', builder => '_build_z' );
+
+        sub _build_x { 3 }
+        sub _build_y { expensive_computation() }
+        sub _build_z { 3 }
+    }
+
+    my $p = Point->new( 'x' => 4 );
+
+    # the result of ->pack will contain:
+    # { x => 4, z => 3 }
+    $p->pack;
+
+=head1 DESCRIPTION
+
+Sometimes you don't want a particular attribute to be part of the
+serialization if it has not been built yet. If you invoke C<Storage()>
+as outlined in the C<Synopsis>, only attributes that have been built
+(ie, where the predicate returns 'true') will be serialized.
+This avoids any potentially expensive computations.
+
+This trait is applied to an instance of L<MooseX::Storage::Engine>, for the
+user-visible version shown in the SYNOPSIS, see L<MooseX::Storage::Traits::OnlyWhenBuilt>
+
+=head1 METHODS
+
+=head2 Introspection
+
+=over 4
+
+=item B<meta>
+
+=back
+
+=head1 BUGS
+
+All complex software has bugs lurking in it, and this module is no
+exception. If you find a bug please either email me, or add the bug
+to cpan-RT.
+
+=head1 AUTHOR
+
+Stevan Little E<lt>stevan.little@iinteractive.comE<gt>
+
+=head1 COPYRIGHT AND LICENSE
+
+Copyright 2007-2008 by Infinity Interactive, Inc.
+
+L<http://www.iinteractive.com>
+
+This library is free software; you can redistribute it and/or modify
+it under the same terms as Perl itself.
+
+=cut
+