MINOR: Avoid coarse lock in Pool#getAndMaybePut
Use `ConcurrentHashMap#computeIfAbsent` which relies on
per key locks.
Reviewers: Ismael Juma
@@ -27,7 +27,6 @@ import collection.JavaConverters._
class Pool[K,V](valueFactory: Option[K => V] = None) extends Iterable[(K, V)] {
private val pool: ConcurrentMap[K, V] = new ConcurrentHashMap[K, V]
- private val createLock = new Object
def put(k: K, v: V): V = pool.put(k, v)
@@ -57,21 +56,10 @@ class Pool[K,V](valueFactory: Option[K => V] = None) extends Iterable[(K, V)] {
* @param createValue Factory function.
* @return The final value associated with the key.
*/
- def getAndMaybePut(key: K, createValue: => V): V = {
- val current = pool.get(key)
- if (current == null) {
- createLock synchronized {
- val current = pool.get(key)
- if (current == null) {
- val value = createValue
- pool.put(key, value)
- value
- }
- else current
- }
- }
- else current
- }
+ def getAndMaybePut(key: K, createValue: => V): V =
+ pool.computeIfAbsent(key, new java.util.function.Function[K, V] {
+ override def apply(k: K): V = createValue
+ })
def contains(id: K): Boolean = pool.containsKey(id)
