org.glassfish.hk2.utilities.general.WeakHashLRU Maven / Gradle / Ivy
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package org.glassfish.hk2.utilities.general;
import org.glassfish.hk2.utilities.cache.CacheKeyFilter;
/**
* @author jwells
*
*/
public interface WeakHashLRU {
/**
* Adds the given key to the LRU. It will
* be placed at the MRU of the LRU. If this
* key already exists in the LRU it will
* be moved to the MRU
*
* @param key Must not be null
*/
public void add(K key);
/**
* Tells if the given key is in the LRU
*
* @param key The key to search for, may not be null
* @return true if found, false otherwise
*/
public boolean contains(K key);
/**
* Removes the given key from the LRU, if found
*
* @param key The key to remove, may not be null
* @return true if removed, false otherwise
*/
public boolean remove(K key);
/**
* Releases all keys that match the filter
*
* @param filter A non-null filter that can be used
* to delete every key that matches the filter
*/
public void releaseMatching(CacheKeyFilter filter);
/**
* 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
*
* @return The number of entries currently
* in the LRU
*/
public int size();
/**
* Removes the key that was Least
* Recently Used
*
* @return The key that was removed, or
* null if the list is empty
*/
public K remove();
/**
* Removes all entries from this LRU
*/
public void clear();
/**
* 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
*/
public void clearStaleReferences();
}