org.apache.accumulo.core.client

Interface BatchWriter

All Known Implementing Classes:

MockBatchWriter

public interface BatchWriter

Send Mutations to a single Table in Accumulo.

When the user uses a Connector to create a BatchWriter, they specify how much memory and how many threads it should use. As the user adds mutations to the batch writer, it buffers them. Once the buffered mutations have used half of the user specified buffer, the mutations are dumped into the background to be written by a thread pool. If the user specified memory completely fills up, then writes are held. When a user calls flush, it does not return until all buffered mutations are written.

In the event that an MutationsRejectedException exception is thrown by one of the methods on a BatchWriter instance, the user should close the current instance and create a new instance. This is a known limitation which will be addressed by ACCUMULO-2990 in the future.

Method Summary

Modifier and Type	Method and Description
void	addMutation(Mutation m) Queues one mutation to write.
void	addMutations(Iterable<Mutation> iterable) Queues several mutations to write.
void	close() Flush and release any resources.
void	flush() Send any buffered mutations to Accumulo immediately.

Method Detail

addMutation

void addMutation(Mutation m)
          throws MutationsRejectedException

Queues one mutation to write.

Parameters:

m - the mutation to add

Throws:

MutationsRejectedException - this could be thrown because current or previous mutations failed

addMutations

void addMutations(Iterable<Mutation> iterable)
           throws MutationsRejectedException

Queues several mutations to write.

Parameters:

iterable - allows adding any number of mutations iteratively

Throws:

MutationsRejectedException - this could be thrown because current or previous mutations failed

flush

void flush()
    throws MutationsRejectedException

Send any buffered mutations to Accumulo immediately.

Throws:

MutationsRejectedException - this could be thrown because current or previous mutations failed

close

void close()
    throws MutationsRejectedException

Flush and release any resources.

Throws:

MutationsRejectedException - this could be thrown because current or previous mutations failed