Package com.google.appengine.api.datastore

Class TransactionOptions

  • public final class TransactionOptions
extends Object
    Describes options for transactions, passed at transaction creation time.

    Notes on usage:
    The recommended way to instantiate a TransactionsOptions object is to statically import TransactionOptions.Builder.* and invoke a static creation method followed by an instance mutator (if needed): 

    
 import static com.google.appengine.api.datastore.TransactionOptions.Builder.*;

 ...

 datastoreService.beginTransaction(withXG(true));

    • Method Detail

      • setXG

        public TransactionOptions setXG​(boolean enable)
        Enable or disable the use of cross-group transactions.
        Parameters:
        enable - true to cross-group transactions, false to restrict transactions to a single entity group.
        Returns:
        this (for chaining)

      • clearXG

        public TransactionOptions clearXG()
        Return the cross-group transaction setting to default (disabled).

      • isXG

        public boolean isXG()
        Returns:
        true if cross-group transactions are allowed, false if they are not allowed.

      • setPreviousTransaction

        public TransactionOptions setPreviousTransaction​(Transaction previousTransaction)
        Set which previous transaction to retry. Can only be used for READ_WRITE transactions. The previous transaction should have been created with the same TransactionOptions, with the exception of the previousTransaction property.

        A rollback is not required, and should not be performed, prior to retrying the transaction.

        Parameters:
        previousTransaction - the transaction to retry.

      • previousTransaction

        public @Nullable Transaction previousTransaction()
        Return the previous transaction that is being retried, or null if none was provided.

      • setTransactionMode

        public TransactionOptions setTransactionMode​(TransactionOptions.Mode mode)
        Set the mode of the transaction.

        Specifying the mode of the transaction can help to improve throughput, as it provides additional information about the intent (or lack of intent, in the case of read only transaction) to perform a write as part of the transaction.

      • transactionMode

        public @Nullable TransactionOptions.Mode transactionMode()
        Return the mode of the transaction, or null if none was specified.

      • equals

        public boolean equals​(@Nullable Object o)
        Overrides:
        equals in class Object

      • hashCode

        public int hashCode()
        Overrides:
        hashCode in class Object