Package org.apache.druid.frame.processor

Class PartitionedOutputChannel

java.lang.Object
org.apache.druid.frame.processor.PartitionedOutputChannel
public class PartitionedOutputChannel extends Object
A channel which can contain multiple partitions of data. It is used by SuperSorter currently to write multiple partitions on the same channel. The readable channel provided to the caller is an instance of PartitionedReadableFrameChannel which allows the caller to open a readable channel for the desired partition.

  • Method Details

    • pair

      public static PartitionedOutputChannel pair(WritableFrameChannel writableChannel, MemoryAllocator frameMemoryAllocator, Supplier<PartitionedReadableFrameChannel> readableChannelSupplier)
      Creates a partitioned output channel pair.
      Parameters:
      writableChannel - writable channel for producer
      frameMemoryAllocator - memory allocator for producer to use while writing frames to the channel
      readableChannelSupplier - partitioned readable channel for consumer. May be called multiple times, so you should wrap this in Suppliers.memoize(com.google.common.base.Supplier<T>) if needed.

    • getWritableChannel

      public WritableFrameChannel getWritableChannel()
      Returns the writable channel of this pair. The producer writes to this channel. Throws ISE if the output channel is read only.

    • getFrameMemoryAllocator

      public MemoryAllocator getFrameMemoryAllocator()
      Returns the memory allocator for the writable channel. The producer uses this to generate frames for the channel. Throws ISE if the output channel is read only.

    • getReadableChannelSupplier

      public Supplier<PartitionedReadableFrameChannel> getReadableChannelSupplier()
      Returns the partitioned readable channel supplier of this pair. The consumer reads from this channel.

    • mapWritableChannel

      public PartitionedOutputChannel mapWritableChannel(Function<WritableFrameChannel,WritableFrameChannel> mapFn)

    • readOnly

      public PartitionedOutputChannel readOnly()
      Returns a read-only version of this instance. Read-only versions have neither getWritableChannel() nor getFrameMemoryAllocator(), and therefore require substantially less memory.

    • convertToReadOnly

      public void convertToReadOnly()
      Removes the reference to the writableChannel and frameMemoryAllocator from the object, making it more efficient