Package org.apache.pinot.query.runtime.operator.utils

Class BlockingMultiStreamConsumer<E>

java.lang.Object

org.apache.pinot.query.runtime.operator.utils.BlockingMultiStreamConsumer<E>

All Implemented Interfaces:

AutoCloseable

Direct Known Subclasses:

BlockingMultiStreamConsumer.OfTransferableBlock

public abstract class BlockingMultiStreamConsumer<E>
extends Object
implements AutoCloseable

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	BlockingMultiStreamConsumer.OfTransferableBlock

Field Summary

Fields

Modifier and Type	Field	Description
protected int	_lastRead	An index that used to calculate where do we are going to start reading.
protected List<? extends AsyncStream<E>>	_mailboxes
protected ArrayBlockingQueue<Boolean>	_newDataReady

Constructor Summary

Constructors

Constructor	Description
BlockingMultiStreamConsumer(Object id, long deadlineMs, List<? extends AsyncStream<E>> asyncProducers)

Method Summary

Modifier and Type	Method	Description
void	cancel(Throwable t)
protected void	cancelRemainingMailboxes()
void	close()
protected abstract boolean	isEos(E element)
protected abstract boolean	isError(E element)
void	onData()
protected abstract E	onEos()
protected abstract E	onException(Exception e)
protected abstract E	onTimeout()
E	readBlockBlocking()	Reads the next block for any ready mailbox or blocks until some of them is ready.

Methods inherited from class java.lang.Object

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

Field Detail

_mailboxes

protected final List<? extends AsyncStream<E>> _mailboxes

_newDataReady

protected final ArrayBlockingQueue<Boolean> _newDataReady

_lastRead

protected int _lastRead

An index that used to calculate where do we are going to start reading. The invariant is that we are always going to start reading from _lastRead + 1. Therefore _lastRead must be in the range [-1, mailbox.size() - 1]

Constructor Detail

BlockingMultiStreamConsumer

public BlockingMultiStreamConsumer(Object id,
                                   long deadlineMs,
                                   List<? extends AsyncStream<E>> asyncProducers)

Method Detail

isError

protected abstract boolean isError(E element)

isEos

protected abstract boolean isEos(E element)

onTimeout

protected abstract E onTimeout()

onException

protected abstract E onException(Exception e)

onEos

protected abstract E onEos()

close

public void close()

Specified by:

close in interface AutoCloseable

cancel

public void cancel(Throwable t)

cancelRemainingMailboxes

protected void cancelRemainingMailboxes()

onData

public void onData()

readBlockBlocking

public E readBlockBlocking()

Reads the next block for any ready mailbox or blocks until some of them is ready. The method implements a sequential read semantic. Meaning that:

1. EOS is only returned when all mailboxes already emitted EOS or there are no mailboxes
2. If an error is read from a mailbox, the error is returned
3. If data is read from a mailbox, that data block is returned
4. If no mailbox is ready, the calling thread is blocked

Right now the implementation tries to be fair. If one call returned the block from mailbox i, then next call will look for mailbox i+1, i+2... in a circular manner. In order to unblock a thread blocked here, onData() should be called. *