org.cache2k.impl

Class PassingStorageAdapter

java.lang.Object

org.cache2k.impl.StorageAdapter

org.cache2k.impl.PassingStorageAdapter

public class PassingStorageAdapter
extends StorageAdapter

Passes cache operation to the storage layer. Implements common services for the storage layer. This class heavily interacts with the base cache and contains mostly everything special needed if a storage is defined. This means the design is not perfectly layered, in some cases the e.g. the get operation does interacts with the underlying storage, wheres iterate

Author:

Jens Wilke; created: 2014-05-08

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	PassingStorageAdapter.Tunable

Constructor Summary

Constructors

Constructor and Description
PassingStorageAdapter(BaseCache _cache, CacheConfig _cacheConfig, StorageConfiguration _storageConfig)

Method Summary

Methods

Modifier and Type	Method and Description
Future<Void>	cancelTimerJobs() may be executed more than once
boolean	checkStorageStillDisconnectedForClear() True means actually no operations started on the storage again, yet
Future<Void>	clearAndReconnect() Called in a (maybe) separate thread after disconnect.
void	disable(String _logMessage, Throwable ex)
void	disable(Throwable ex)
void	disableAndThrow(String _logMessage, Throwable ex)
void	disconnectStorageForClear() Disconnect storage so cache can wait for all entry operations to finish.
void	evict(Entry e) If passivation is not enabled, then we need to do nothing here since, the entry was transferred to the storage on the StorageAdapter.put(Entry, long) operation.
void	expire(Entry e) An expired entry was removed from the memory cache and can also be removed from the storage.
void	flush() Initiate flush on the storage.
StorageEntry	get(Object k)
int	getAlert() orange alert level if buffer is active, so we get alerted if storage clear isn't finished.
CacheStorage	getImplementation()
int	getTotalEntryCount() Calculates the cache size, depending on the persistence configuration
ClosableIterator<Entry>	iterateAll()
protected void	logLifecycleOperation(String s) By default log lifecycle operations as info.
protected void	onFlushTimerEvent()
void	open()
void	purge()
void	put(Entry e, long _nextRefreshTime) Store entry on cache put.
boolean	remove(Object key)
Future<Void>	shutdown()
String	toString()

Methods inherited from class org.cache2k.impl.StorageAdapter

buildThrowable, rethrow

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

PassingStorageAdapter

public PassingStorageAdapter(BaseCache _cache,
                     CacheConfig _cacheConfig,
                     StorageConfiguration _storageConfig)

Method Detail

logLifecycleOperation

protected void logLifecycleOperation(String s)

By default log lifecycle operations as info.

open

public void open()

Specified by:

open in class StorageAdapter

put

public void put(Entry e,
       long _nextRefreshTime)

Store entry on cache put. Entry must be locked, since we use the entry directly for handing it over to the storage, it is not allowed to change. The expiry time in the entry does not have a valid value yet, so that is why it is transferred separately.

Specified by:

put in class StorageAdapter

_nextRefreshTime - value expiry time in millis, 0: expire immediately, Long.MAX_VALUE: no expiry

get

public StorageEntry get(Object k)

Specified by:

get in class StorageAdapter

evict

public void evict(Entry e)

If passivation is not enabled, then we need to do nothing here since, the entry was transferred to the storage on the StorageAdapter.put(Entry, long) operation. With passivation enabled, the entries need to be transferred when evicted from the heap.

The storage operation is done in the calling thread, which should be a client thread. The cache client will be throttled until the I/O operation is finished. This is what we want in general. To decouple it, we need to implement async storage I/O support.

Specified by:

evict in class StorageAdapter

expire

public void expire(Entry e)

An expired entry was removed from the memory cache and can also be removed from the storage. For the moment, this does nothing, since we cannot do the removal in the calling thread and decoupling yields bad race conditions. Expired entries in the storage are remove by the purge run.

Specified by:

expire in class StorageAdapter

remove

public boolean remove(Object key)

Specified by:

remove in class StorageAdapter

iterateAll

public ClosableIterator<Entry> iterateAll()

Specified by:

iterateAll in class StorageAdapter

purge

public void purge()

Specified by:

purge in class StorageAdapter

onFlushTimerEvent

protected void onFlushTimerEvent()

flush

public void flush()

Initiate flush on the storage. If a concurrent flush is going on, wait for it until initiating a new one.

Specified by:

flush in class StorageAdapter

cancelTimerJobs

public Future<Void> cancelTimerJobs()

may be executed more than once

Specified by:

cancelTimerJobs in class StorageAdapter

shutdown

public Future<Void> shutdown()

Specified by:

shutdown in class StorageAdapter

checkStorageStillDisconnectedForClear

public boolean checkStorageStillDisconnectedForClear()

True means actually no operations started on the storage again, yet

Specified by:

checkStorageStillDisconnectedForClear in class StorageAdapter

disconnectStorageForClear

public void disconnectStorageForClear()

Disconnect storage so cache can wait for all entry operations to finish.

Specified by:

disconnectStorageForClear in class StorageAdapter

clearAndReconnect

public Future<Void> clearAndReconnect()

Called in a (maybe) separate thread after disconnect. Cache already is doing operations meanwhile and the storage operations are buffered. Here we have multiple race conditions. A clear() exists immediately but the storage is still working on the first clear. All previous clear processes will be cancelled and the last one may win. However, this method is not necessarily executed in the order the clear or the disconnect took place. This is checked also.

Specified by:

clearAndReconnect in class StorageAdapter

disableAndThrow

public void disableAndThrow(String _logMessage,
                   Throwable ex)

disable

public void disable(String _logMessage,
           Throwable ex)

disable

public void disable(Throwable ex)

Specified by:

disable in class StorageAdapter

getAlert

public int getAlert()

orange alert level if buffer is active, so we get alerted if storage clear isn't finished.

Specified by:

getAlert in class StorageAdapter

getTotalEntryCount

public int getTotalEntryCount()

Calculates the cache size, depending on the persistence configuration

Specified by:

getTotalEntryCount in class StorageAdapter

See Also:

Cache.getTotalEntryCount()

toString

public String toString()

Overrides:

toString in class Object

getImplementation

public CacheStorage getImplementation()