Package org.apache.geode.cache

Interface TransactionWriter

All Superinterfaces:

CacheCallback, Declarable

public interface TransactionWriter
extends CacheCallback

A callback that is allowed to veto a transaction. Only one TransactionWriter can exist per cache, and only one TransactionWriter will be fired in the entire distributed system for each transaction.

This writer can be used to update a backend data source before the GemFire cache is updated during commit. If the backend update fails, the implementer can throw a TransactionWriterException to veto the transaction.

WARNING: To avoid risk of deadlock, do not invoke CacheFactory.getAnyInstance() from within any callback methods. Instead use TransactionEvent.getCache().

Since:

GemFire 6.5

See Also:

• CacheTransactionManager.setWriter(org.apache.geode.cache.TransactionWriter)

Method Summary

Modifier and Type	Method	Description
void	beforeCommit(TransactionEvent event)	Called before the transaction has finished committing, but after conflict checking.

Methods inherited from interface org.apache.geode.cache.CacheCallback

close

Methods inherited from interface org.apache.geode.cache.Declarable

init, initialize

Method Details

beforeCommit

void beforeCommit(TransactionEvent event)
           throws TransactionWriterException

Called before the transaction has finished committing, but after conflict checking. Provides an opportunity for implementors to cause transaction abort by throwing a TransactionWriterException

Parameters:

event - the TransactionEvent

Throws:

TransactionWriterException - in the event that the transaction should be rolled back

See Also:

• CacheTransactionManager.commit()