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package cbt
import java.net._
import java.util.concurrent.ConcurrentHashMap
class ClassLoaderCache(logger: Logger){
val persistent = new KeyLockedLazyCache(
NailgunLauncher.classLoaderCache.asInstanceOf[ConcurrentHashMap[String,AnyRef]],
NailgunLauncher.classLoaderCache.asInstanceOf[ConcurrentHashMap[AnyRef,ClassLoader]],
Some(logger)
)
val transient = new KeyLockedLazyCache(
new ConcurrentHashMap[String,AnyRef],
new ConcurrentHashMap[AnyRef,ClassLoader],
Some(logger)
)
}
private[cbt] class LockableKey
/**
A cache that lazily computes values if needed during lookup.
Locking occurs on the key, so separate keys can be looked up
simultaneously without a deadlock.
*/
final private[cbt] class KeyLockedLazyCache[Key <: AnyRef,Value <: AnyRef](
keys: ConcurrentHashMap[Key,AnyRef],
builds: ConcurrentHashMap[AnyRef,Value],
logger: Option[Logger]
){
def get( key: Key, value: => Value ): Value = {
val keyObject = keys.synchronized{
if( ! (keys containsKey key) ){
val keyObject = new LockableKey
logger.foreach(_.resolver("CACHE MISS: " ++ key.toString))
keys.put( key, keyObject )
keyObject
} else {
val keyObject = keys get key
logger.foreach(_.resolver("CACHE HIT: " ++ keyObject.toString ++ " -> " ++ key.toString))
keyObject
}
}
import collection.JavaConversions._
//logger.resolver("CACHE: \n" ++ keys.mkString("\n"))
// synchronizing on key only, so asking for a particular key does
// not block the whole cache, but just that cache entry
key.synchronized{
if( ! (builds containsKey keyObject) ){
builds.put( keyObject, value )
}
builds get keyObject
}
}
def remove( key: Key ) = keys.synchronized{
if( (keys containsKey key) ){
keys.put( key, new LockableKey )
}
val keyObject = keys get key
keys.remove( key )
builds.remove( keyObject )
}
}
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