co.cask.cdap.data2.transaction.queue

Class AbstractQueueConsumer

java.lang.Object

co.cask.cdap.data2.transaction.queue.AbstractQueueConsumer

All Implemented Interfaces:

QueueConsumer, co.cask.tephra.TransactionAware, Closeable, AutoCloseable

Direct Known Subclasses:

LevelDBQueueConsumer

public abstract class AbstractQueueConsumer
extends Object
implements QueueConsumer, co.cask.tephra.TransactionAware

Common queue consumer for persisting engines such as HBase and LevelDB.

Field Summary

Fields

Modifier and Type	Field and Description
protected int	commitCount
protected byte[]	stateColumnName
protected co.cask.tephra.Transaction	transaction

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	AbstractQueueConsumer(CConfiguration cConf, ConsumerConfig consumerConfig, QueueName queueName)
protected	AbstractQueueConsumer(CConfiguration cConf, ConsumerConfig consumerConfig, QueueName queueName, byte[] startRow)

Method Summary

Methods

Modifier and Type	Method and Description
protected abstract boolean	claimEntry(byte[] rowKey, byte[] stateContent)
boolean	commitTx()
DequeueResult<byte[]>	dequeue() Dequeue an entry from the queue.
DequeueResult<byte[]>	dequeue(int maxBatchSize) Dequeue multiple entries from the queue.
ConsumerConfig	getConfig() Returns the configuration of this consumer.
QueueName	getQueueName() Returns the queue name that this consumer is working on.
protected abstract QueueScanner	getScanner(byte[] startRow, byte[] stopRow, int numRows)
String	getTransactionAwareName()
Collection<byte[]>	getTxChanges()
boolean	rollbackTx()
void	startTx(co.cask.tephra.Transaction tx)
protected abstract void	undoState(Set<byte[]> rowKeys, byte[] stateColumnName)
protected void	updateStartRow(byte[] startRow) Called when the start row is updated.
protected abstract void	updateState(Set<byte[]> rowKeys, byte[] stateColumnName, byte[] stateContent)
void	updateTx(co.cask.tephra.Transaction transaction)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface java.io.Closeable

close

Methods inherited from interface co.cask.tephra.TransactionAware

postTxCommit

Field Detail

stateColumnName

protected final byte[] stateColumnName

transaction

protected co.cask.tephra.Transaction transaction

commitCount

protected int commitCount

Constructor Detail

AbstractQueueConsumer

protected AbstractQueueConsumer(CConfiguration cConf,
                     ConsumerConfig consumerConfig,
                     QueueName queueName)

AbstractQueueConsumer

protected AbstractQueueConsumer(CConfiguration cConf,
                     ConsumerConfig consumerConfig,
                     QueueName queueName,
                     @Nullable
                     byte[] startRow)

Method Detail

claimEntry

protected abstract boolean claimEntry(byte[] rowKey,
                 byte[] stateContent)
                               throws IOException

Throws:

IOException

updateState

protected abstract void updateState(Set<byte[]> rowKeys,
               byte[] stateColumnName,
               byte[] stateContent)
                             throws IOException

Throws:

IOException

undoState

protected abstract void undoState(Set<byte[]> rowKeys,
             byte[] stateColumnName)
                           throws IOException,
                                  InterruptedException

Throws:

IOException

InterruptedException

getScanner

protected abstract QueueScanner getScanner(byte[] startRow,
                      byte[] stopRow,
                      int numRows)
                                    throws IOException

Throws:

IOException

getQueueName

public QueueName getQueueName()

Description copied from interface: QueueConsumer

Returns the queue name that this consumer is working on.

Specified by:

getQueueName in interface QueueConsumer

getConfig

public ConsumerConfig getConfig()

Description copied from interface: QueueConsumer

Returns the configuration of this consumer.

Specified by:

getConfig in interface QueueConsumer

dequeue

public DequeueResult<byte[]> dequeue()
                              throws IOException

Description copied from interface: QueueConsumer

Dequeue an entry from the queue.

Specified by:

dequeue in interface QueueConsumer

Returns:

A DequeueResult.

Throws:

IOException

dequeue

public DequeueResult<byte[]> dequeue(int maxBatchSize)
                              throws IOException

Description copied from interface: QueueConsumer

Dequeue multiple entries from the queue. The dequeue result may have less entries than the given maxBatchSize, depending on how many entries in the queue.

Specified by:

dequeue in interface QueueConsumer

Parameters:

maxBatchSize - Maximum number of entries to queue.

Returns:

A DequeueResult.

Throws:

IOException

startTx

public void startTx(co.cask.tephra.Transaction tx)

Specified by:

startTx in interface co.cask.tephra.TransactionAware

updateTx

public void updateTx(co.cask.tephra.Transaction transaction)

Specified by:

updateTx in interface co.cask.tephra.TransactionAware

getTxChanges

public Collection<byte[]> getTxChanges()

Specified by:

getTxChanges in interface co.cask.tephra.TransactionAware

commitTx

public boolean commitTx()
                 throws Exception

Specified by:

commitTx in interface co.cask.tephra.TransactionAware

Throws:

Exception

rollbackTx

public boolean rollbackTx()
                   throws Exception

Specified by:

rollbackTx in interface co.cask.tephra.TransactionAware

Throws:

Exception

updateStartRow

protected void updateStartRow(byte[] startRow)

Called when the start row is updated.

getTransactionAwareName

public String getTransactionAwareName()

Specified by:

getTransactionAwareName in interface co.cask.tephra.TransactionAware