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 queryjava.lang.IllegalStateException - If txn is not null and the txn is not activeTransaction 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()
Transactions started by this thread upon which no
attempt to commit or rollback has been made.