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.\"
.IX Title "Data::ObjectDriver::Driver::BaseCache 3pm"
.TH Data::ObjectDriver::Driver::BaseCache 3pm "2017-09-30" "perl v5.26.0" "User Contributed Perl Documentation"
.\" For nroff, turn off justification.  Always turn off hyphenation; it makes
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.SH "NAME"
Data::ObjectDriver::Driver::BaseCache \- parent class for caching object drivers
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
Data::ObjectDriver::Driver::BaseCache provides behavior utilized for all
caching object drivers for use with Data::ObjectDriver. That behavior is
looking up requested objects in a cache, and falling back to another
Data::ObjectDriver for a cache miss.
.SH "USAGE"
.IX Header "USAGE"
Drivers based on Data::ObjectDriver::Driver::BaseCache support all standard
operations for Data::ObjectDriver object drivers (lookup, search, update,
insert, replace, remove, and fetch_data). BaseCache-derived drivers also support:
.ie n .SS """Data::ObjectDriver::Driver::BaseCache\->new( %params )"""
.el .SS "\f(CWData::ObjectDriver::Driver::BaseCache\->new( %params )\fP"
.IX Subsection "Data::ObjectDriver::Driver::BaseCache->new( %params )"
Creates a new instance of a BaseCache driver. Required members of \f(CW%params\fR are:
.IP "\(bu" 4
\&\f(CW\*(C`cache\*(C'\fR
.Sp
The object with which to interface with the external cache. For example, for
the \f(CW\*(C`Memcached\*(C'\fR caching object driver, the value of the \f(CW\*(C`cache\*(C'\fR member should
be a \f(CW\*(C`Cache::Memcached\*(C'\fR object.
.IP "\(bu" 4
\&\f(CW\*(C`fallback\*(C'\fR
.Sp
The \f(CW\*(C`Data::ObjectDriver\*(C'\fR object driver to which to fall back when the cache
does not yet contain a requested object. The \f(CW\*(C`fallback\*(C'\fR member is also the
object driver to which updates and inserts are passed.
.ie n .SS """$driver\->cache_key($class, $primary_key)"""
.el .SS "\f(CW$driver\->cache_key($class, $primary_key)\fP"
.IX Subsection "$driver->cache_key($class, $primary_key)"
Returns the cache key for an object of the given class with the given primary
key. The cache key is used with the external cache to identify an object.
.PP
In BaseCache's implementation, the key is the class name and all the column
names of the primary key concatenated, separated by single colons.
.ie n .SS """$driver\->get_multi_from_cache(@cache_keys)"""
.el .SS "\f(CW$driver\->get_multi_from_cache(@cache_keys)\fP"
.IX Subsection "$driver->get_multi_from_cache(@cache_keys)"
Returns the objects corresponding to the given cache keys, as represented in
the external cache.
.ie n .SS """Data::ObjectDriver::Driver::BaseClass\->Disabled([ $value ])"""
.el .SS "\f(CWData::ObjectDriver::Driver::BaseClass\->Disabled([ $value ])\fP"
.IX Subsection "Data::ObjectDriver::Driver::BaseClass->Disabled([ $value ])"
Returns whether caches of the given class are disabled, first updating the
disabled state of drivers of the given class to \f(CW$value\fR, if given. When a
caching driver is disabled, all operations are automatically passed through to
the fallback object driver.
.PP
Note that, if you disable and re-enable a caching driver, some of the cached
data may be invalid due to updates that were performed while the driver was
disabled not being reflected in the external cache.
.SH "SUBCLASSING"
.IX Header "SUBCLASSING"
When creating a caching driver from \f(CW\*(C`BaseCache\*(C'\fR, the behavior for interaction
with the external cache (through the \f(CW\*(C`cache\*(C'\fR member of the constructor) must
be defined by implementing these methods:
.ie n .SS """$driver\->add_to_cache($cache_key, $obj_repr)"""
.el .SS "\f(CW$driver\->add_to_cache($cache_key, $obj_repr)\fP"
.IX Subsection "$driver->add_to_cache($cache_key, $obj_repr)"
Sets the cache entry for \f(CW$cache_key\fR to the given object representation. This
method is used when the corresponding object is being saved to the database for
the first time.
.ie n .SS """$driver\->update_cache($cache_key, $obj_repr)"""
.el .SS "\f(CW$driver\->update_cache($cache_key, $obj_repr)\fP"
.IX Subsection "$driver->update_cache($cache_key, $obj_repr)"
Sets the cache entry for \f(CW$cache_key\fR to the given object representation. This
method is used when the corresponding object already exists in the database and
is being saved.
.ie n .SS """$driver\->remove_from_cache($cache_key)"""
.el .SS "\f(CW$driver\->remove_from_cache($cache_key)\fP"
.IX Subsection "$driver->remove_from_cache($cache_key)"
Clears the given cache entry. This method is used when the corresponding object
is being deleted from the database.
.ie n .SS """$driver\->get_from_cache($cache_key)"""
.el .SS "\f(CW$driver\->get_from_cache($cache_key)\fP"
.IX Subsection "$driver->get_from_cache($cache_key)"
Returns the object corresponding to the given cache key, as it exists in the
external cache.
.ie n .SS """$driver\->inflate($class, $obj_repr)"""
.el .SS "\f(CW$driver\->inflate($class, $obj_repr)\fP"
.IX Subsection "$driver->inflate($class, $obj_repr)"
Returns an instance of \f(CW$class\fR containing the data in the representation
\&\f(CW$obj_repr\fR, as returned from the \f(CW\*(C`get_from_cache\*(C'\fR method.
.PP
In BaseCache's implementation, no operation is performed. \f(CW\*(C`get_from_cache\*(C'\fR
should itself return the appropriate instances of
\&\f(CW\*(C`Data::ObjectDriver::BaseObject\*(C'\fR.
.ie n .SS """$driver\->deflate($obj)"""
.el .SS "\f(CW$driver\->deflate($obj)\fP"
.IX Subsection "$driver->deflate($obj)"
Returns a representation of the given \f(CW\*(C`Data::ObjectDriver::BaseObject\*(C'\fR
instance, suitable for passing to the \f(CW\*(C`add_to_cache\*(C'\fR and \f(CW\*(C`update_cache\*(C'\fR
methods.
.PP
In BaseCache's implementation, no operation is performed. \f(CW\*(C`add_to_cache\*(C'\fR and
\&\f(CW\*(C`update_cache\*(C'\fR should themselves accept \f(CW\*(C`Data::ObjectDriver::BaseObject\*(C'\fR
instances.
.SH "LICENSE"
.IX Header "LICENSE"
\&\fIData::ObjectDriver\fR is free software; you may redistribute it and/or modify
it under the same terms as Perl itself.
.SH "AUTHOR & COPYRIGHT"
.IX Header "AUTHOR & COPYRIGHT"
Except where otherwise noted, \fIData::ObjectDriver\fR is Copyright 2005\-2006
Six Apart, cpan@sixapart.com. All rights reserved.