Package org.apache.druid.frame.channel
Class ReadableByteChunksFrameChannel
- java.lang.Object
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- org.apache.druid.frame.channel.ReadableByteChunksFrameChannel
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- All Implemented Interfaces:
Closeable
,AutoCloseable
,ReadableFrameChannel
public class ReadableByteChunksFrameChannel extends Object implements ReadableFrameChannel
Channel backed by a byte stream that is continuously streamed in usingaddChunk(byte[])
. The byte stream must be in the format of aFrameFile
. This class is used byFrameFileHttpResponseHandler
to provide nonblocking reads from a remote http server.
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description com.google.common.util.concurrent.ListenableFuture<?>
addChunk(byte[] chunk)
Adds a chunk of bytes.boolean
canRead()
Returns whether this channel has a frame or error condition currently available.void
close()
Releases any resources associated with this readable channel.static ReadableByteChunksFrameChannel
create(String id, boolean framesOnly)
Create a channel that aims to limit its memory footprint to one frame.void
doneWriting()
Call method when caller is done adding chunks.long
getBytesAdded()
String
getId()
boolean
isErrorOrFinished()
boolean
isFinished()
Returns whether this channel is finished.Frame
read()
Returns the next available frame from this channel.com.google.common.util.concurrent.ListenableFuture<?>
readabilityFuture()
Returns a future that will resolve when eitherReadableFrameChannel.isFinished()
orReadableFrameChannel.canRead()
would return true.void
setError(Throwable t)
Clears the channel and replaces it with the given error.
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Method Detail
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create
public static ReadableByteChunksFrameChannel create(String id, boolean framesOnly)
Create a channel that aims to limit its memory footprint to one frame. The channel exerts backpressure fromaddChunk(byte[])
immediately once a full frame has been buffered.
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addChunk
@Nullable public com.google.common.util.concurrent.ListenableFuture<?> addChunk(byte[] chunk)
Adds a chunk of bytes. If this chunk forms a full frame, it will immediately become available for reading. Otherwise, the bytes will be buffered until a full frame is encountered. Returns a backpressure future if the amount of queued bytes is at or above this channel's limit. If the return future is nonnull, callers are politely requested to wait for the future to resolve before adding additional chunks. (This is not enforced; addChunk will continue to accept new chunks even if the channel is over its limit.) When done adding chunks calldoneWriting
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setError
public void setError(Throwable t)
Clears the channel and replaces it with the given error. After calling this method, no additional chunks will be accepted.
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doneWriting
public void doneWriting()
Call method when caller is done adding chunks.
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isFinished
public boolean isFinished()
Description copied from interface:ReadableFrameChannel
Returns whether this channel is finished. Finished channels will not generate any further frames or errors. Generally, once you discover that a channel is finished, you should callReadableFrameChannel.close()
and then discard it. Note that it is possible for a channel to be unfinished and also have no available frames or errors. This happens when it is not in a ready-for-reading state. SeeReadableFrameChannel.readabilityFuture()
for details.- Specified by:
isFinished
in interfaceReadableFrameChannel
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canRead
public boolean canRead()
Description copied from interface:ReadableFrameChannel
Returns whether this channel has a frame or error condition currently available. If this method returns true, then you can callReadableFrameChannel.read()
to retrieve the frame or error. Note that it is possible for a channel to be unfinished and also have no available frames or errors. This happens when it is not in a ready-for-reading state. SeeReadableFrameChannel.readabilityFuture()
for details.- Specified by:
canRead
in interfaceReadableFrameChannel
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read
public Frame read()
Description copied from interface:ReadableFrameChannel
Returns the next available frame from this channel. Before calling this method, you should checkReadableFrameChannel.canRead()
to ensure there is a frame or error available.- Specified by:
read
in interfaceReadableFrameChannel
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readabilityFuture
public com.google.common.util.concurrent.ListenableFuture<?> readabilityFuture()
Description copied from interface:ReadableFrameChannel
Returns a future that will resolve when eitherReadableFrameChannel.isFinished()
orReadableFrameChannel.canRead()
would return true. The future will never resolve to an exception. If something exceptional has happened, the exception can be retrieved fromReadableFrameChannel.read()
.- Specified by:
readabilityFuture
in interfaceReadableFrameChannel
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close
public void close()
Description copied from interface:ReadableFrameChannel
Releases any resources associated with this readable channel. After calling this, you should not call any other methods on the channel.- Specified by:
close
in interfaceAutoCloseable
- Specified by:
close
in interfaceCloseable
- Specified by:
close
in interfaceReadableFrameChannel
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getId
public String getId()
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getBytesAdded
public long getBytesAdded()
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isErrorOrFinished
public boolean isErrorOrFinished()
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