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Diffstat (limited to 'lib/DBD/Gofer/Policy/Base.pm')
| -rw-r--r-- | lib/DBD/Gofer/Policy/Base.pm | 162 |
1 files changed, 162 insertions, 0 deletions
diff --git a/lib/DBD/Gofer/Policy/Base.pm b/lib/DBD/Gofer/Policy/Base.pm new file mode 100644 index 0000000..1725b03 --- /dev/null +++ b/lib/DBD/Gofer/Policy/Base.pm @@ -0,0 +1,162 @@ +package DBD::Gofer::Policy::Base; + +# $Id: Base.pm 10087 2007-10-16 12:42:37Z timbo $ +# +# Copyright (c) 2007, Tim Bunce, Ireland +# +# You may distribute under the terms of either the GNU General Public +# License or the Artistic License, as specified in the Perl README file. + +use strict; +use warnings; +use Carp; + +our $VERSION = sprintf("0.%06d", q$Revision: 10087 $ =~ /(\d+)/o); +our $AUTOLOAD; + +my %policy_defaults = ( + # force connect method (unless overridden by go_connect_method=>'...' attribute) + # if false: call same method on client as on server + connect_method => 'connect', + # force prepare method (unless overridden by go_prepare_method=>'...' attribute) + # if false: call same method on client as on server + prepare_method => 'prepare', + skip_connect_check => 0, + skip_default_methods => 0, + skip_prepare_check => 0, + skip_ping => 0, + dbh_attribute_update => 'every', + dbh_attribute_list => ['*'], + locally_quote => 0, + locally_quote_identifier => 0, + cache_parse_trace_flags => 1, + cache_parse_trace_flag => 1, + cache_data_sources => 1, + cache_type_info_all => 1, + cache_tables => 0, + cache_table_info => 0, + cache_column_info => 0, + cache_primary_key_info => 0, + cache_foreign_key_info => 0, + cache_statistics_info => 0, + cache_get_info => 0, + cache_func => 0, +); + +my $base_policy_file = $INC{"DBD/Gofer/Policy/Base.pm"}; + +__PACKAGE__->create_policy_subs(\%policy_defaults); + +sub create_policy_subs { + my ($class, $policy_defaults) = @_; + + while ( my ($policy_name, $policy_default) = each %$policy_defaults) { + my $policy_attr_name = "go_$policy_name"; + my $sub = sub { + # $policy->foo($attr, ...) + #carp "$policy_name($_[1],...)"; + # return the policy default value unless an attribute overrides it + return (ref $_[1] && exists $_[1]->{$policy_attr_name}) + ? $_[1]->{$policy_attr_name} + : $policy_default; + }; + no strict 'refs'; + *{$class . '::' . $policy_name} = $sub; + } +} + +sub AUTOLOAD { + carp "Unknown policy name $AUTOLOAD used"; + # only warn once + no strict 'refs'; + *$AUTOLOAD = sub { undef }; + return undef; +} + +sub new { + my ($class, $args) = @_; + my $policy = {}; + bless $policy, $class; +} + +sub DESTROY { }; + +1; + +=head1 NAME + +DBD::Gofer::Policy::Base - Base class for DBD::Gofer policies + +=head1 SYNOPSIS + + $dbh = DBI->connect("dbi:Gofer:transport=...;policy=...", ...) + +=head1 DESCRIPTION + +DBD::Gofer can be configured via a 'policy' mechanism that allows you to +fine-tune the number of round-trips to the Gofer server. The policies are +grouped into classes (which may be subclassed) and referenced by the name of +the class. + +The L<DBD::Gofer::Policy::Base> class is the base class for all the policy +classes and describes all the individual policy items. + +The Base policy is not used directly. You should use a policy class derived from it. + +=head1 POLICY CLASSES + +Three policy classes are supplied with DBD::Gofer: + +L<DBD::Gofer::Policy::pedantic> is most 'transparent' but slowest because it +makes more round-trips to the Gofer server. + +L<DBD::Gofer::Policy::classic> is a reasonable compromise - it's the default policy. + +L<DBD::Gofer::Policy::rush> is fastest, but may require code changes in your applications. + +Generally the default C<classic> policy is fine. When first testing an existing +application with Gofer it is a good idea to start with the C<pedantic> policy +first and then switch to C<classic> or a custom policy, for final testing. + +=head1 POLICY ITEMS + +These are temporary docs: See the source code for list of policies and their defaults. + +In a future version the policies and their defaults will be defined in the pod and parsed out at load-time. + +See the source code to this module for more details. + +=head1 POLICY CUSTOMIZATION + +XXX This area of DBD::Gofer is subject to change. + +There are three ways to customize policies: + +Policy classes are designed to influence the overall behaviour of DBD::Gofer +with existing, unaltered programs, so they work in a reasonably optimal way +without requiring code changes. You can implement new policy classes as +subclasses of existing policies. + +In many cases individual policy items can be overridden on a case-by-case basis +within your application code. You do this by passing a corresponding +C<<go_<policy_name>>> attribute into DBI methods by your application code. +This let's you fine-tune the behaviour for special cases. + +The policy items are implemented as methods. In many cases the methods are +passed parameters relating to the DBD::Gofer code being executed. This means +the policy can implement dynamic behaviour that varies depending on the +particular circumstances, such as the particular statement being executed. + +=head1 AUTHOR + +Tim Bunce, L<http://www.tim.bunce.name> + +=head1 LICENCE AND COPYRIGHT + +Copyright (c) 2007, Tim Bunce, Ireland. All rights reserved. + +This module is free software; you can redistribute it and/or +modify it under the same terms as Perl itself. See L<perlartistic>. + +=cut + |