public final class DoubleBarrelLRUCache<K extends DoubleBarrelLRUCache.CloneableKey,V>
- extends Object
Simple concurrent LRU cache, using a "double barrel"
approach where two ConcurrentHashMaps record entries.
At any given time, one hash is primary and the other
get(K) first checks primary, and if
that's a miss, checks secondary. If secondary has the
entry, it's promoted to primary (NOTE: the key is
cloned at this point). Once primary is full, the
secondary is cleared and the two are swapped.
This is not as space efficient as other possible
concurrent approaches (see LUCENE-2075): to achieve
perfect LRU(N) it requires 2*N storage. But, this
approach is relatively simple and seems in practice to
not grow unbounded in size when under hideously high
- NOTE: This API is for Lucene internal purposes only and might change in incompatible ways in the next release.
|Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
public DoubleBarrelLRUCache(int maxSize)
public V get(K key)
public void put(K key,
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