NAME

Cache::CacheMetaData -- data about objects in the cache

DESCRIPTION

The CacheMetaData object is used by size aware caches to keep track of the state of the cache and effeciently return information such as an objects size or an ordered list of indentifiers to be removed when a cache size is being limited. End users will not normally use CacheMetaData directly.

SYNOPSIS

 use Cache::CacheMetaData;

 my $cache_meta_data = new Cache::CacheMetaData( );

 foreach my $key ( $cache->get_keys( ) )
 {
    my $object = $cache->get_object( $key ) or
      next;

    $cache_meta_data->insert( $object );
  }

 my $current_size = $cache_meta_data->get_cache_size( );

 my @removal_list = $cache_meta_data->build_removal_list( );

METHODS

new( )

Construct a new Cache::CacheMetaData object

insert( $object )

Inform the CacheMetaData about the object $object in the cache.

remove( $key )

Inform the CacheMetaData that the object specified by $key is no longer in the cache.

build_removal_list( )

Create a list of the keys in the cache, ordered as follows:

1) objects that expire now

2) objects expiring at a particular time, with ties broken by the time at which they were least recently accessed

3) objects that never expire, sub ordered by the time at which they were least recently accessed

NOTE: This could be improved further by taking the size into account on accessed_at ties. However, this type of tie is unlikely in normal usage.

build_object_size( $key )

Return the size of an object specified by $key.

PROPERTIES

get_cache_size: The total size of the objects in the cache

AUTHOR

Original author: DeWitt Clinton <dewitt@unto.net>