com.google.cloud.datastore

Interface Datastore

All Superinterfaces:

DatastoreReader, DatastoreReaderWriter, DatastoreWriter, Service<DatastoreOptions>

public interface Datastore
extends Service<DatastoreOptions>, DatastoreReaderWriter

An interface for Google Cloud Datastore.

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static interface	Datastore.TransactionCallable<T> A callback for running with a transactional DatastoreReaderWriter.

Method Summary

Methods

Modifier and Type	Method and Description
List<Key>	allocateId(IncompleteKey... key) Returns a list of keys using the allocated ids ordered by the input.
Key	allocateId(IncompleteKey key) Allocate a unique id for the given key.
void	delete(Key... key) A datastore delete operation.
List<Entity>	fetch(Iterable<Key> keys, ReadOption... options) Returns a list with a value for each given key (ordered by input).
Iterator<Entity>	get(Iterable<Key> keys, ReadOption... options) Returns an Entity for each given Key that exists in the Datastore.
Entity	get(Key key, ReadOption... options) Returns an Entity for the given Key or null if it doesn't exist.
Batch	newBatch() Returns a new Batch for processing multiple write operations in one request.
KeyFactory	newKeyFactory() Returns a new KeyFactory for this service
Transaction	newTransaction() Returns a new Datastore transaction.
void	put(Entity... entity) A Datastore put (a.k.a upsert) operation.
<T> QueryResults<T>	run(Query<T> query, ReadOption... options) Submits a Query and returns its result.
<T> T	runInTransaction(Datastore.TransactionCallable<T> callable) Invokes the callback's Datastore.TransactionCallable.run(com.google.cloud.datastore.DatastoreReaderWriter) method with a DatastoreReaderWriter that is associated with a new transaction.
void	update(Entity... entity) A Datastore update operation.

Methods inherited from interface com.google.cloud.Service

options

Methods inherited from interface com.google.cloud.datastore.DatastoreReader

fetch, get, get, run

Methods inherited from interface com.google.cloud.datastore.DatastoreWriter

add, add

Method Detail

newTransaction

Transaction newTransaction()

Returns a new Datastore transaction.

Throws:

DatastoreException - upon failure

runInTransaction

<T> T runInTransaction(Datastore.TransactionCallable<T> callable)

Invokes the callback's Datastore.TransactionCallable.run(com.google.cloud.datastore.DatastoreReaderWriter) method with a DatastoreReaderWriter that is associated with a new transaction. The transaction will be committed upon successful invocation. Any thrown exception will cause the transaction to rollback and will be propagated as a DatastoreException with the original exception as its root cause.

Parameters:

callable - the callback to call with a newly created transactional readerWriter

Throws:

DatastoreException - upon failure

newBatch

Batch newBatch()

Returns a new Batch for processing multiple write operations in one request.

allocateId

Key allocateId(IncompleteKey key)

Allocate a unique id for the given key. The returned key will have the same information (projectId, kind, namespace and ancestors) as the given key and will have a newly assigned id.

Throws:

DatastoreException - upon failure

allocateId

List<Key> allocateId(IncompleteKey... key)

Returns a list of keys using the allocated ids ordered by the input.

Throws:

DatastoreException - upon failure

See Also:

allocateId(IncompleteKey)

update

void update(Entity... entity)

A Datastore update operation. The operation will fail if an entity with the same key does not already exist.

Specified by:

update in interface DatastoreWriter

Throws:

DatastoreException - upon failure

put

void put(Entity... entity)

A Datastore put (a.k.a upsert) operation. The operation will add or modify the entities.

Specified by:

put in interface DatastoreWriter

Throws:

DatastoreException - upon failure

delete

void delete(Key... key)

A datastore delete operation. It is OK request a deletion of a non-existing entity.

Specified by:

delete in interface DatastoreWriter

Throws:

DatastoreException - upon failure

newKeyFactory

KeyFactory newKeyFactory()

Returns a new KeyFactory for this service

get

Entity get(Key key,
         ReadOption... options)

Returns an Entity for the given Key or null if it doesn't exist. ReadOptions can be specified if desired.

Throws:

DatastoreException - upon failure

get

Iterator<Entity> get(Iterable<Key> keys,
                   ReadOption... options)

Returns an Entity for each given Key that exists in the Datastore. The order of the result is unspecified. Results are loaded lazily, so it is possible to get a DatastoreException from the returned Iterator's hasNext or next methods. ReadOptions can be specified if desired.

Throws:

DatastoreException - upon failure

See Also:

DatastoreReader.get(Key)

fetch

List<Entity> fetch(Iterable<Key> keys,
                 ReadOption... options)

Returns a list with a value for each given key (ordered by input). null values are returned for nonexistent keys. When possible prefer using DatastoreReader.get(Key...) to avoid eagerly loading the results. ReadOptions can be specified if desired.

run

<T> QueryResults<T> run(Query<T> query,
                      ReadOption... options)

Submits a Query and returns its result. ReadOptions can be specified if desired.

Throws:

DatastoreException - upon failure