org.apache.nifi.distributed.cache.client

Class CacheClientHandshakeHandler

java.lang.Object

io.netty.channel.ChannelHandlerAdapter

io.netty.channel.ChannelInboundHandlerAdapter

org.apache.nifi.distributed.cache.client.CacheClientHandshakeHandler

All Implemented Interfaces:

io.netty.channel.ChannelHandler, io.netty.channel.ChannelInboundHandler

public class CacheClientHandshakeHandler
extends io.netty.channel.ChannelInboundHandlerAdapter

The ChannelHandler responsible for performing the client handshake with the distributed cache server.

Nested Class Summary

Nested classes/interfaces inherited from interface io.netty.channel.ChannelHandler

io.netty.channel.ChannelHandler.Sharable

Field Summary

Fields

Modifier and Type	Field and Description
private org.slf4j.Logger	logger
private static byte[]	MAGIC_HEADER The header bytes used to initiate the server handshake.
private io.netty.channel.ChannelPromise	promiseHandshakeComplete The synchronization construct used to signal the client application that the handshake has finished.
private AtomicInteger	protocol The version of the protocol negotiated between the client and server.
private static int	PROTOCOL_UNINITIALIZED
private VersionNegotiator	versionNegotiator The coordinator used to broker the version of the distributed cache protocol with the service.

Constructor Summary

Constructors

Constructor and Description
CacheClientHandshakeHandler(io.netty.channel.Channel channel, VersionNegotiator versionNegotiator) Constructor.

Method Summary

Modifier and Type	Method and Description
void	channelActive(io.netty.channel.ChannelHandlerContext ctx)
void	channelRead(io.netty.channel.ChannelHandlerContext ctx, Object msg)
void	channelReadComplete(io.netty.channel.ChannelHandlerContext ctx)
VersionNegotiator	getVersionNegotiator()
private void	processHandshake(io.netty.channel.ChannelHandlerContext ctx, io.netty.buffer.ByteBuf byteBuf) Negotiate distributed cache protocol version with remote service.
void	waitHandshakeComplete() API providing client application with visibility into the handshake process.

Methods inherited from class io.netty.channel.ChannelInboundHandlerAdapter

channelInactive, channelRegistered, channelUnregistered, channelWritabilityChanged, exceptionCaught, userEventTriggered

Methods inherited from class io.netty.channel.ChannelHandlerAdapter

ensureNotSharable, handlerAdded, handlerRemoved, isSharable

Methods inherited from class java.lang.Object

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

Methods inherited from interface io.netty.channel.ChannelHandler

handlerAdded, handlerRemoved

Field Detail

PROTOCOL_UNINITIALIZED

private static final int PROTOCOL_UNINITIALIZED

See Also:

Constant Field Values

logger

private final org.slf4j.Logger logger

MAGIC_HEADER

private static final byte[] MAGIC_HEADER

The header bytes used to initiate the server handshake.

promiseHandshakeComplete

private final io.netty.channel.ChannelPromise promiseHandshakeComplete

The synchronization construct used to signal the client application that the handshake has finished.

protocol

private final AtomicInteger protocol

The version of the protocol negotiated between the client and server.

versionNegotiator

private final VersionNegotiator versionNegotiator

The coordinator used to broker the version of the distributed cache protocol with the service.

Constructor Detail

CacheClientHandshakeHandler

public CacheClientHandshakeHandler(io.netty.channel.Channel channel,
                                   VersionNegotiator versionNegotiator)

Constructor.

Parameters:

channel - the channel to which this ChannelHandler is bound.

versionNegotiator - coordinator used to broker the version of the distributed cache protocol with the service

Method Detail

waitHandshakeComplete

public void waitHandshakeComplete()

API providing client application with visibility into the handshake process. Distributed cache requests should not be sent using this Channel until the handshake is complete.

getVersionNegotiator

public VersionNegotiator getVersionNegotiator()

Returns:

the coordinator used to broker the version of the distributed cache protocol with the service

channelActive

public void channelActive(io.netty.channel.ChannelHandlerContext ctx)
                   throws IOException

Specified by:

channelActive in interface io.netty.channel.ChannelInboundHandler

Overrides:

channelActive in class io.netty.channel.ChannelInboundHandlerAdapter

Throws:

IOException

channelRead

public void channelRead(io.netty.channel.ChannelHandlerContext ctx,
                        Object msg)

Specified by:

channelRead in interface io.netty.channel.ChannelInboundHandler

Overrides:

channelRead in class io.netty.channel.ChannelInboundHandlerAdapter

processHandshake

private void processHandshake(io.netty.channel.ChannelHandlerContext ctx,
                              io.netty.buffer.ByteBuf byteBuf)
                       throws HandshakeException,
                              IOException

Negotiate distributed cache protocol version with remote service.

Parameters:

ctx - the Channel context

byteBuf - the byte stream received from the remote service

Throws:

HandshakeException - on failure to negotiate protocol version

IOException - on write failure

channelReadComplete

public void channelReadComplete(io.netty.channel.ChannelHandlerContext ctx)

Specified by:

channelReadComplete in interface io.netty.channel.ChannelInboundHandler

Overrides:

channelReadComplete in class io.netty.channel.ChannelInboundHandlerAdapter