Package org.apache.druid.frame.channel

Class ComposingWritableFrameChannel

java.lang.Object

org.apache.druid.frame.channel.ComposingWritableFrameChannel

All Implemented Interfaces:

Closeable, AutoCloseable, WritableFrameChannel

public class ComposingWritableFrameChannel
extends Object
implements WritableFrameChannel

A composed writable channel to write frames. The channel can encapsulate multiple writable channels in it and automatically switches to next channels once the current write channel cannot allow more writes.

Field Summary

Fields inherited from interface org.apache.druid.frame.channel.WritableFrameChannel

NO_PARTITION

Constructor Summary

Constructors

Constructor	Description
ComposingWritableFrameChannel(Integer partitionNumber, List<Supplier<OutputChannel>> outputChannelSuppliers, List<Supplier<PartitionedOutputChannel>> partitionedOutputChannelSuppliers, List<Supplier<WritableFrameChannel>> writableChannelSuppliers, Map<Integer,HashSet<Integer>> partitionToChannelMap)	Create a new channel.

Method Summary

Modifier and Type	Method	Description
void	close()	Finish writing to this channel.
void	fail(Throwable cause)	Called prior to WritableFrameChannel.close() if the writer has failed.
boolean	isClosed()	Whether WritableFrameChannel.close() has been called on this channel.
com.google.common.util.concurrent.ListenableFuture<?>	writabilityFuture()	Returns a future that resolves when WritableFrameChannel.write(org.apache.druid.query.rowsandcols.RowsAndColumns, int) is able to receive a new batch of data without blocking or throwing an exception.
void	write(RowsAndColumns rac, int partitionNum)	Writes a batch of data with an attached partition number.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.druid.frame.channel.WritableFrameChannel

write, write, write

Constructor Details

ComposingWritableFrameChannel

public ComposingWritableFrameChannel(@Nullable
 Integer partitionNumber,
 @Nullable
 List<Supplier<OutputChannel>> outputChannelSuppliers,
 @Nullable
 List<Supplier<PartitionedOutputChannel>> partitionedOutputChannelSuppliers,
 List<Supplier<WritableFrameChannel>> writableChannelSuppliers,
 Map<Integer,HashSet<Integer>> partitionToChannelMap)

Create a new channel.

Parameters:

partitionNumber - partition number for a single-partition channel, or null for a multi-partition channel

outputChannelSuppliers - one supplier per composed channel, if this is a single-partition channel

partitionedOutputChannelSuppliers - one supplier per composed channel, if this is a multi-partition channel

writableChannelSuppliers - one supplier per composed channel

partitionToChannelMap - empty map that will be populated with the set of valid channels for each partition

Method Details

write

public void write(RowsAndColumns rac,
 int partitionNum)
           throws IOException

Description copied from interface: WritableFrameChannel

Writes a batch of data with an attached partition number. May throw an exception if WritableFrameChannel.writabilityFuture() is unresolved.

Specified by:

write in interface WritableFrameChannel

Throws:

IOException

fail

public void fail(@Nullable
 Throwable cause)
          throws IOException

Description copied from interface: WritableFrameChannel

Called prior to WritableFrameChannel.close() if the writer has failed. Must be followed by a call to WritableFrameChannel.close().

Specified by:

fail in interface WritableFrameChannel

Parameters:

cause - optional cause of failure. Used by the in-memory channel BlockingQueueFrameChannel.Writable to propagate exeptions to downstream processors. Most other channels ignore the provided cause.

Throws:

IOException

close

public void close()
           throws IOException

Description copied from interface: WritableFrameChannel

Finish writing to this channel. When this method is called without WritableFrameChannel.fail(Throwable) having previously been called, the writer is understood to have completed successfully. After calling this method, no additional calls to WritableFrameChannel.write(org.apache.druid.query.rowsandcols.RowsAndColumns, int), WritableFrameChannel.fail(Throwable), or this method are permitted.

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

Specified by:

close in interface WritableFrameChannel

Throws:

IOException

isClosed

public boolean isClosed()

Description copied from interface: WritableFrameChannel

Whether WritableFrameChannel.close() has been called on this channel.

Specified by:

isClosed in interface WritableFrameChannel

writabilityFuture

public com.google.common.util.concurrent.ListenableFuture<?> writabilityFuture()

Description copied from interface: WritableFrameChannel

Returns a future that resolves when WritableFrameChannel.write(org.apache.druid.query.rowsandcols.RowsAndColumns, int) is able to receive a new batch of data without blocking or throwing an exception. The future never resolves to an exception.

Specified by:

writabilityFuture in interface WritableFrameChannel