A sample list-update policy.
This class serves to show the interface a list update functor needs to support.
Defined in: sample_update_policy.hpp
| Method | Description | 
| sample_update_policy () | Default constructor. Must be default constructable. | 
| sample_update_policy (const sample_update_policy &other) | Copy constructor. Must be copy constructable. | 
| inline void swap (sample_update_policy &other) | Swaps content. Must be swappable (if there is such a word). | 
| Type | Definition | Description | 
| metadata_type | Some metadata type. | Metadata on which this functor operates. The class must declare the metadata type on which it operates; the list-update based containers will append to each node an object of this type. | 
| Method | Description | 
| metadata_type operator() () const | Creates a metadata object. A list-update based container object will call this method to create a metadata type when a node is created. | 
| bool operator() (metadata_reference r_data) const | Decides whether a metadata object should be moved to the front of the list. A list-update based containers object will call this method to decide whether to move a node to the front of the list. The method should return true if the node should be moved to the front of the list. metadata_reference is a reference to a metadata_type. |