Package org.apache.arrow.vector.ipc.message

Class MessageChannelReader

java.lang.Object

org.apache.arrow.vector.ipc.message.MessageChannelReader

All Implemented Interfaces:

AutoCloseable

public class MessageChannelReader
extends Object
implements AutoCloseable

Reads a sequence of messages using a ReadChannel.

Field Summary

Fields

Modifier and Type	Field	Description
protected BufferAllocator	allocator
protected ReadChannel	in

Constructor Summary

Constructors

Constructor	Description
MessageChannelReader(ReadChannel in, BufferAllocator allocator)	Construct a MessageReader to read streaming messages from an existing ReadChannel.

Method Summary

Modifier and Type	Method	Description
long	bytesRead()	Get the number of bytes read from the ReadChannel.
void	close()	Close the ReadChannel.
MessageResult	readNext()	Read a message from the ReadChannel and return a MessageResult containing the Message metadata and optional message body data.

Methods inherited from class java.lang.Object

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

Field Details

in

protected ReadChannel in

allocator

protected BufferAllocator allocator

Constructor Details

MessageChannelReader

public MessageChannelReader(ReadChannel in,
 BufferAllocator allocator)

Construct a MessageReader to read streaming messages from an existing ReadChannel.

Parameters:

in - Channel to read messages from

allocator - BufferAllocator used to read Message body into an ArrowBuf.

Method Details

readNext

public MessageResult readNext()
                       throws IOException

Read a message from the ReadChannel and return a MessageResult containing the Message metadata and optional message body data. Once the end-of-stream has been reached, a null value will be returned. If the message has no body, then MessageResult.getBodyBuffer() returns null.

Returns:

MessageResult or null if reached end-of-stream

Throws:

IOException - on error

bytesRead

public long bytesRead()

Get the number of bytes read from the ReadChannel.

Returns:

number of bytes

close

public void close()
           throws IOException

Close the ReadChannel.

Specified by:

close in interface AutoCloseable

Throws:

IOException - on error