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authorLorry Tar Creator <lorry-tar-importer@baserock.org>2012-06-06 16:41:29 +0000
committerLorry <lorry@roadtrain.codethink.co.uk>2012-09-26 13:46:50 +0000
commit7c48e67cf07ee41bfde7139a62bb232bd23a4a48 (patch)
tree6d7686b5075bd5cba253dabf2e6c302acb3a147c /lib/DBD/Gofer/Policy/Base.pm
downloadperl-dbi-tarball-7c48e67cf07ee41bfde7139a62bb232bd23a4a48.tar.gz
Imported from /srv/lorry/lorry-area/perl-dbi-tarball/DBI-1.622.tar.gz.HEADDBI-1.622master
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+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
+