com.googlecode.objectify.cache

Class CachingAsyncDatastoreService

java.lang.Object

com.googlecode.objectify.cache.CachingAsyncDatastoreService

All Implemented Interfaces:

com.google.appengine.api.datastore.AsyncDatastoreService, com.google.appengine.api.datastore.BaseDatastoreService

public class CachingAsyncDatastoreService
extends Object
implements com.google.appengine.api.datastore.AsyncDatastoreService

A write-through memcache for Entity objects that works for both transactional and nontransactional sessions.

• Caches negative results as well as positive results.
• Queries do not affect the cache in any way.
• Transactional reads bypass the cache, but successful transaction commits will update the cache.
• This cache has near-transactional integrity. As long as DeadlineExceededException is not hit, cache should not go out of sync even under heavy contention.

Note: Until Google adds a hook that lets us wrap native Future implementations, you muse install the AsyncCacheFilter to use this cache asynchronously. This is not necessary for synchronous use of CachingDatastoreService, but asynchronous operation requires an extra hook for the end of a request when fired-and-forgotten put()s and delete()s get processed. If you use this cache asynchronously, and you do not use the AsyncCacheFilter, your cache will go out of sync.

Author:

Jeff Schnitzer

Constructor Summary

Constructors

Constructor and Description
CachingAsyncDatastoreService(com.google.appengine.api.datastore.AsyncDatastoreService rawAsync, EntityMemcache memcache)

Method Summary

Modifier and Type	Method and Description
Future<com.google.appengine.api.datastore.KeyRange>	allocateIds(com.google.appengine.api.datastore.Key parent, String kind, long num)
Future<com.google.appengine.api.datastore.KeyRange>	allocateIds(String kind, long num)
Future<com.google.appengine.api.datastore.Transaction>	beginTransaction()
Future<com.google.appengine.api.datastore.Transaction>	beginTransaction(com.google.appengine.api.datastore.TransactionOptions options)
Future<Void>	delete(Iterable<com.google.appengine.api.datastore.Key> keys)
Future<Void>	delete(com.google.appengine.api.datastore.Key... keys)
Future<Void>	delete(com.google.appengine.api.datastore.Transaction txn, Iterable<com.google.appengine.api.datastore.Key> keys)
Future<Void>	delete(com.google.appengine.api.datastore.Transaction txn, com.google.appengine.api.datastore.Key... keys)
Future<Map<com.google.appengine.api.datastore.Key,com.google.appengine.api.datastore.Entity>>	get(Iterable<com.google.appengine.api.datastore.Key> keys)
Future<com.google.appengine.api.datastore.Entity>	get(com.google.appengine.api.datastore.Key key)
Future<Map<com.google.appengine.api.datastore.Key,com.google.appengine.api.datastore.Entity>>	get(com.google.appengine.api.datastore.Transaction txn, Iterable<com.google.appengine.api.datastore.Key> keys)
Future<com.google.appengine.api.datastore.Entity>	get(com.google.appengine.api.datastore.Transaction txn, com.google.appengine.api.datastore.Key key)
Collection<com.google.appengine.api.datastore.Transaction>	getActiveTransactions()
com.google.appengine.api.datastore.Transaction	getCurrentTransaction()
com.google.appengine.api.datastore.Transaction	getCurrentTransaction(com.google.appengine.api.datastore.Transaction txn)
Future<com.google.appengine.api.datastore.DatastoreAttributes>	getDatastoreAttributes()
Future<Map<com.google.appengine.api.datastore.Index,com.google.appengine.api.datastore.Index.IndexState>>	getIndexes()
com.google.appengine.api.datastore.PreparedQuery	prepare(com.google.appengine.api.datastore.Query query)
com.google.appengine.api.datastore.PreparedQuery	prepare(com.google.appengine.api.datastore.Transaction txn, com.google.appengine.api.datastore.Query query)
Future<com.google.appengine.api.datastore.Key>	put(com.google.appengine.api.datastore.Entity entity)
Future<List<com.google.appengine.api.datastore.Key>>	put(Iterable<com.google.appengine.api.datastore.Entity> entities)
Future<com.google.appengine.api.datastore.Key>	put(com.google.appengine.api.datastore.Transaction txn, com.google.appengine.api.datastore.Entity entity)
Future<List<com.google.appengine.api.datastore.Key>>	put(com.google.appengine.api.datastore.Transaction txn, Iterable<com.google.appengine.api.datastore.Entity> entities)

Methods inherited from class java.lang.Object

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

Constructor Detail

CachingAsyncDatastoreService

public CachingAsyncDatastoreService(com.google.appengine.api.datastore.AsyncDatastoreService rawAsync,
                                    EntityMemcache memcache)

Method Detail

allocateIds

public Future<com.google.appengine.api.datastore.KeyRange> allocateIds(String kind,
                                                                       long num)

Specified by:

allocateIds in interface com.google.appengine.api.datastore.AsyncDatastoreService

allocateIds

public Future<com.google.appengine.api.datastore.KeyRange> allocateIds(com.google.appengine.api.datastore.Key parent,
                                                                       String kind,
                                                                       long num)

Specified by:

allocateIds in interface com.google.appengine.api.datastore.AsyncDatastoreService

beginTransaction

public Future<com.google.appengine.api.datastore.Transaction> beginTransaction()

Specified by:

beginTransaction in interface com.google.appengine.api.datastore.AsyncDatastoreService

beginTransaction

public Future<com.google.appengine.api.datastore.Transaction> beginTransaction(com.google.appengine.api.datastore.TransactionOptions options)

Specified by:

beginTransaction in interface com.google.appengine.api.datastore.AsyncDatastoreService

delete

public Future<Void> delete(com.google.appengine.api.datastore.Key... keys)

Specified by:

delete in interface com.google.appengine.api.datastore.AsyncDatastoreService

delete

public Future<Void> delete(Iterable<com.google.appengine.api.datastore.Key> keys)

Specified by:

delete in interface com.google.appengine.api.datastore.AsyncDatastoreService

delete

public Future<Void> delete(com.google.appengine.api.datastore.Transaction txn,
                           com.google.appengine.api.datastore.Key... keys)

Specified by:

delete in interface com.google.appengine.api.datastore.AsyncDatastoreService

delete

public Future<Void> delete(com.google.appengine.api.datastore.Transaction txn,
                           Iterable<com.google.appengine.api.datastore.Key> keys)

Specified by:

delete in interface com.google.appengine.api.datastore.AsyncDatastoreService

get

public Future<com.google.appengine.api.datastore.Entity> get(com.google.appengine.api.datastore.Key key)

Specified by:

get in interface com.google.appengine.api.datastore.AsyncDatastoreService

get

public Future<Map<com.google.appengine.api.datastore.Key,com.google.appengine.api.datastore.Entity>> get(Iterable<com.google.appengine.api.datastore.Key> keys)

Specified by:

get in interface com.google.appengine.api.datastore.AsyncDatastoreService

get

public Future<com.google.appengine.api.datastore.Entity> get(com.google.appengine.api.datastore.Transaction txn,
                                                             com.google.appengine.api.datastore.Key key)

Specified by:

get in interface com.google.appengine.api.datastore.AsyncDatastoreService

get

public Future<Map<com.google.appengine.api.datastore.Key,com.google.appengine.api.datastore.Entity>> get(com.google.appengine.api.datastore.Transaction txn,
                                                                                                         Iterable<com.google.appengine.api.datastore.Key> keys)

Specified by:

get in interface com.google.appengine.api.datastore.AsyncDatastoreService

getActiveTransactions

public Collection<com.google.appengine.api.datastore.Transaction> getActiveTransactions()

Specified by:

getActiveTransactions in interface com.google.appengine.api.datastore.BaseDatastoreService

getCurrentTransaction

public com.google.appengine.api.datastore.Transaction getCurrentTransaction()

Specified by:

getCurrentTransaction in interface com.google.appengine.api.datastore.BaseDatastoreService

getCurrentTransaction

public com.google.appengine.api.datastore.Transaction getCurrentTransaction(com.google.appengine.api.datastore.Transaction txn)

Specified by:

getCurrentTransaction in interface com.google.appengine.api.datastore.BaseDatastoreService

prepare

public com.google.appengine.api.datastore.PreparedQuery prepare(com.google.appengine.api.datastore.Query query)

Specified by:

prepare in interface com.google.appengine.api.datastore.BaseDatastoreService

prepare

public com.google.appengine.api.datastore.PreparedQuery prepare(com.google.appengine.api.datastore.Transaction txn,
                                                                com.google.appengine.api.datastore.Query query)

Specified by:

prepare in interface com.google.appengine.api.datastore.BaseDatastoreService

put

public Future<com.google.appengine.api.datastore.Key> put(com.google.appengine.api.datastore.Entity entity)

Specified by:

put in interface com.google.appengine.api.datastore.AsyncDatastoreService

put

public Future<List<com.google.appengine.api.datastore.Key>> put(Iterable<com.google.appengine.api.datastore.Entity> entities)

Specified by:

put in interface com.google.appengine.api.datastore.AsyncDatastoreService

put

public Future<com.google.appengine.api.datastore.Key> put(com.google.appengine.api.datastore.Transaction txn,
                                                          com.google.appengine.api.datastore.Entity entity)

Specified by:

put in interface com.google.appengine.api.datastore.AsyncDatastoreService

put

public Future<List<com.google.appengine.api.datastore.Key>> put(com.google.appengine.api.datastore.Transaction txn,
                                                                Iterable<com.google.appengine.api.datastore.Entity> entities)

Specified by:

put in interface com.google.appengine.api.datastore.AsyncDatastoreService

getDatastoreAttributes

public Future<com.google.appengine.api.datastore.DatastoreAttributes> getDatastoreAttributes()

Specified by:

getDatastoreAttributes in interface com.google.appengine.api.datastore.AsyncDatastoreService

getIndexes

public Future<Map<com.google.appengine.api.datastore.Index,com.google.appengine.api.datastore.Index.IndexState>> getIndexes()

Specified by:

getIndexes in interface com.google.appengine.api.datastore.AsyncDatastoreService