This class is a GenericCache subclass implementing an LRU
(Least Recently Used) cache replacement policy. In other words,
values are added to the cache until it becomes full. Once the
cache is full, when a new value is added to the cache, it replaces
the least recently used value currently in the cache. This is probably
the best general purpose cache replacement policy.
public final void addElement(java.lang.Object key,
java.lang.Object value)
Adds a value to the cache. If the cache is full, when a new value
is added to the cache, it replaces the first of the current values
in the cache to have been added (i.e., FIFO).