java.lang.Object
org.apache.lucene.util.DoubleBarrelLRUCache<K,V>
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
is secondary. 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
load.
- NOTE: This API is for internal purposes only and might change in incompatible ways in the next release.
Method Summary |
V |
get(K key)
|
void |
put(K key,
V value)
|
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
DoubleBarrelLRUCache
public DoubleBarrelLRUCache(int maxSize)
get
public V get(K key)
put
public void put(K key,
V value)
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