NAME

       Data::ObjectDriver::Driver::BaseCache - parent class for caching object drivers

SYNOPSIS

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.

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:

   "Data::ObjectDriver::Driver::BaseCache->new( %params )"
       Creates a new instance of a BaseCache driver. Required members of %params are:

       •   "cache"

           The object with which to interface with the external cache. For example, for the
           "Memcached" caching object driver, the value of the "cache" member should be a
           "Cache::Memcached" object.

       •   "fallback"

           The "Data::ObjectDriver" object driver to which to fall back when the cache does not
           yet contain a requested object. The "fallback" member is also the object driver to
           which updates and inserts are passed.

   "$driver->cache_key($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.

       In BaseCache's implementation, the key is the class name and all the column names of the
       primary key concatenated, separated by single colons.

   "$driver->get_multi_from_cache(@cache_keys)"
       Returns the objects corresponding to the given cache keys, as represented in the external
       cache.

   "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 $value, if given. When a caching driver is disabled, all
       operations are automatically passed through to the fallback object driver.

       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.

SUBCLASSING

       When creating a caching driver from "BaseCache", the behavior for interaction with the
       external cache (through the "cache" member of the constructor) must be defined by
       implementing these methods:

   "$driver->add_to_cache($cache_key, $obj_repr)"
       Sets the cache entry for $cache_key to the given object representation. This method is
       used when the corresponding object is being saved to the database for the first time.

   "$driver->update_cache($cache_key, $obj_repr)"
       Sets the cache entry for $cache_key to the given object representation. This method is
       used when the corresponding object already exists in the database and is being saved.

   "$driver->remove_from_cache($cache_key)"
       Clears the given cache entry. This method is used when the corresponding object is being
       deleted from the database.

   "$driver->get_from_cache($cache_key)"
       Returns the object corresponding to the given cache key, as it exists in the external
       cache.

   "$driver->inflate($class, $obj_repr)"
       Returns an instance of $class containing the data in the representation $obj_repr, as
       returned from the "get_from_cache" method.

       In BaseCache's implementation, no operation is performed. "get_from_cache" should itself
       return the appropriate instances of "Data::ObjectDriver::BaseObject".

   "$driver->deflate($obj)"
       Returns a representation of the given "Data::ObjectDriver::BaseObject" instance, suitable
       for passing to the "add_to_cache" and "update_cache" methods.

       In BaseCache's implementation, no operation is performed. "add_to_cache" and
       "update_cache" should themselves accept "Data::ObjectDriver::BaseObject" instances.

LICENSE

       Data::ObjectDriver is free software; you may redistribute it and/or modify it under the
       same terms as Perl itself.

AUTHOR & COPYRIGHT

       Except where otherwise noted, Data::ObjectDriver is Copyright 2005-2006 Six Apart,
       cpan@sixapart.com. All rights reserved.