text: package simplelru
  
  // LRUCache is the interface for simple LRU cache.
  type LRUCache interface {
  	// Adds a value to the cache, returns true if an eviction occurred and
  	// updates the "recently used"-ness of the key.
  	Add(key, value interface{}) bool
  
  	// Returns key's value from the cache and
  	// updates the "recently used"-ness of the key. #value, isFound
  	Get(key interface{}) (value interface{}, ok bool)
  
  	// Check if a key exsists in cache without updating the recent-ness.
  	Contains(key interface{}) (ok bool)
  
  	// Returns key's value without updating the "recently used"-ness of the key.
  	Peek(key interface{}) (value interface{}, ok bool)
  
  	// Removes a key from the cache.
  	Remove(key interface{}) bool
  
  	// Removes the oldest entry from cache.
  	RemoveOldest() (interface{}, interface{}, bool)
  
  	// Returns the oldest entry from the cache. #key, value, isFound
  	GetOldest() (interface{}, interface{}, bool)
  
  	// Returns a slice of the keys in the cache, from oldest to newest.
  	Keys() []interface{}
  
  	// Returns the number of items in the cache.
  	Len() int
  
  	// Clear all cache entries
  	Purge()
  }
  