public interface BaseDatastoreService
DatastoreService
and
AsyncDatastoreService
.
Modifier and Type | Method and Description |
---|---|
java.util.Collection<
Transaction
>
|
getActiveTransactions
()
|
Transaction
|
getCurrentTransaction
()
Returns the current transaction for this thread, or throws an exception if
there is no current transaction.
|
Transaction
|
getCurrentTransaction
(
Transaction
returnedIfNoTxn)
Returns the current transaction for this thread, or returns the parameter
if there is no current transaction.
|
PreparedQuery
|
prepare
(
Query
query)
Prepares a query for execution.
|
PreparedQuery
|
prepare
(
Transaction
txn,
Query
query)
Exhibits the same behavior as
prepare(Query)
, but executes within
the provided transaction.
|
PreparedQuery prepare(Query query)
This method returns a
PreparedQuery
which can be used
to execute and retrieve results from the datastore for
query
.
This operation will not execute in a transaction even if there is a current
transaction and the provided query is an ancestor query. This operation
also ignores the
ImplicitTransactionManagementPolicy
. If you are
preparing an ancestory query and you want it to execute in a transaction,
use
prepare(Transaction, Query)
.
query
- a not
null Query
.
null PreparedQuery
.
PreparedQuery prepare(Transaction txn, Query query)
prepare(Query)
, but executes within
the provided transaction. It is up to the caller to commit or
rollback. Transaction can be null.
java.lang.IllegalArgumentException
- If txn is not null and query is not an
ancestor query
java.lang.IllegalStateException
- If txn is not null and the txn is not active
Transaction getCurrentTransaction()
java.util.NoSuchElementException
- If there is no current transaction.
Transaction getCurrentTransaction(Transaction returnedIfNoTxn)
null
or provide
your own object to represent null. See
getCurrentTransaction()
for a definition of "current transaction."
Use this method when you're not sure if there is a current transaction.
returnedIfNoTxn
- The return value of this method if there is no
current transaction. Can be null.
java.util.Collection<Transaction> getActiveTransactions()
Transaction
s started by this thread upon which no
attempt to commit or rollback has been made.