Interface WeakHashClock<K,V>

All Known Implementing Classes:
WeakHashClockImpl

public interface WeakHashClock<K,V>
This is a clock (if non-empty the next verb will always return a new value in a cycle) that can also get values in O(1) complexity. This HashClock also has Weak key references, so if the key becomes unavailable it will not be retrievable from the get operation and the next operation will remove it from the clock
  • Method Summary

    Modifier and Type
    Method
    Description
    void
    Sets the clock size back to zero, no entries
    void
    Causes stale references to be cleared from the data structures.
    get(K key)
    Gets the given key, returning null if not found
    boolean
    Tells if this WeakHashClock has Weak keys
    Returns the next key/value pair in the clock, or null if the clock has no members.
    void
    put(K key, V value)
    Adds the given pair to the clock.
    void
    Releases all key/value pairs that match the filter
    remove(K key)
    Removes the given key from the clock, if found
    int
    Returns the number of elements currently in the clock.
  • Method Details

    • put

      void put(K key, V value)
      Adds the given pair to the clock. It will be placed at the current tail of the clock
      Parameters:
      key - Must not be null
      value - May not be null
    • get

      V get(K key)
      Gets the given key, returning null if not found
      Parameters:
      key - The key to search for, may not be null
      Returns:
      The value found, or null if not found
    • remove

      V remove(K key)
      Removes the given key from the clock, if found
      Parameters:
      key - The key to remove, may not be null
      Returns:
      The value removed if found, or null if not found
    • releaseMatching

      void releaseMatching(CacheKeyFilter<K> filter)
      Releases all key/value pairs that match the filter
      Parameters:
      filter - A non-null filter that can be used to delete every key/value pair that matches the filter
    • size

      int size()
      Returns the number of elements currently in the clock. References that have gone away because they were weakly referenced will not be counted in the size
      Returns:
      The number of entries currently in the clock
    • next

      Map.Entry<K,V> next()
      Returns the next key/value pair in the clock, or null if the clock has no members. This will advance the head and tail of the clock to the next element. If the WeakReference for the returned element is null then this element will also have been removed from the clock by this operation
      Returns:
      The next key/value pair in the
    • clear

      void clear()
      Sets the clock size back to zero, no entries
    • clearStaleReferences

      void clearStaleReferences()
      Causes stale references to be cleared from the data structures. Since this is a weak clock the references can go away at any time, which happens whenever any operation has been performed. However, it may be the case that no operation will be performed for a while and so this method is provided to have a no-op operation to call in order to clear out any stale references
    • hasWeakKeys

      boolean hasWeakKeys()
      Tells if this WeakHashClock has Weak keys
      Returns:
      true if this map has weak keys, true otherwise