public T get ( E key ) { Entry < E , T > entry = null ; synchronized ( this ) { entry = map . get ( key ) ; if ( map . get ( key ) == null ) return null ; entry . prev . next = entry . next ; entry . next . prev = entry . prev ; entry . prev = this . head ; entry . next = this . head . next ; this . head . next . prev = entry ; this . head . next = entry ; } return entry . value ; }
get a element from map with specified key