alluxio.client.block.stream

Class GrpcDataReader

java.lang.Object

alluxio.client.block.stream.GrpcDataReader

All Implemented Interfaces:

DataReader, Closeable, AutoCloseable

@NotThreadSafe
public final class GrpcDataReader
extends Object
implements DataReader

A gRPC data reader that streams a region from gRPC data server. Protocol: 1. The client sends a read request (id, offset, length). 2. Once the server receives the request, it streams chunks to the client. The streaming pauses if the server's buffer is full and resumes if the buffer is not full. 3. The client reads chunks from the stream using an iterator. 4. The client can cancel the read request at anytime. The cancel request is ignored by the server if everything has been sent to channel. 5. To make it simple to handle errors, the channel is closed if any error occurs.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	GrpcDataReader.Factory Factory class to create GrpcDataReaders.

Method Summary

Modifier and Type	Method and Description
void	close()
long	pos()
alluxio.network.protocol.databuffer.DataBuffer	readChunk() Reads a chunk.

Methods inherited from class java.lang.Object

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

Method Detail

pos

public long pos()

Specified by:

pos in interface DataReader

Returns:

the current stream position

readChunk

public alluxio.network.protocol.databuffer.DataBuffer readChunk()
                                                         throws IOException

Description copied from interface: DataReader

Reads a chunk. The caller needs to release the chunk.

Specified by:

readChunk in interface DataReader

Returns:

the data buffer or null if EOF is reached

Throws:

IOException

close

public void close()
           throws IOException

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Throws:

IOException