edu.umass.cs.nio

Class JSONMessenger<NodeIDType>

java.lang.Object

edu.umass.cs.nio.JSONMessenger<NodeIDType>

Type Parameters:

NodeIDType - This class has support for retransmissions with exponential backoff. But you can't rely on this backoff for anything other than ephemeral traffic bursts. If you are overloaded, you are overloaded, so you must just reduce the load.

All Implemented Interfaces:

AddressMessenger<org.json.JSONObject>, InterfaceNIOTransport<NodeIDType,org.json.JSONObject>, Messenger<NodeIDType,org.json.JSONObject>, SSLMessenger<NodeIDType,org.json.JSONObject>

Direct Known Subclasses:

PaxosMessenger

public class JSONMessenger<NodeIDType>
extends java.lang.Object
implements SSLMessenger<NodeIDType,org.json.JSONObject>

Author:

V. Arun

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	JSONMessenger.JSONObjectByteableWrapper
static class	JSONMessenger.JSONObjectWrapper

Field Summary

Fields

Modifier and Type	Field and Description
protected java.util.concurrent.ScheduledExecutorService	execpool
static java.lang.String	SENT_TIME The JSON key for the time when the message was sent.

Constructor Summary

Constructors

Constructor and Description
JSONMessenger(InterfaceNIOTransport<NodeIDType,org.json.JSONObject> niot)
JSONMessenger(InterfaceNIOTransport<NodeIDType,org.json.JSONObject> niot, int numWorkers)

Method Summary

Modifier and Type	Method and Description
void	addPacketDemultiplexer(AbstractPacketDemultiplexer<?> pd)
AddressMessenger<org.json.JSONObject>	getClientMessenger()
AddressMessenger<org.json.JSONObject>	getClientMessenger(java.net.InetSocketAddress listenSockAddr)
java.net.InetSocketAddress	getListeningSocketAddress()
NodeIDType	getMyID()
protected InterfaceNIOTransport<NodeIDType,org.json.JSONObject>	getNIOTransport()
NodeConfig<NodeIDType>	getNodeConfig()
AddressMessenger<org.json.JSONObject>	getSSLClientMessenger()
SSLDataProcessingWorker.SSL_MODES	getSSLMode()
boolean	isDisconnected(NodeIDType node)
boolean	isStopped()
void	precedePacketDemultiplexer(AbstractPacketDemultiplexer<?> pd)
void	send(GenericMessagingTask<NodeIDType,?> mtask)
protected void	send(GenericMessagingTask<NodeIDType,?> mtask, boolean useWorkers) Send returns void because it is the "ultimate" send.
void	sendClient(java.net.InetSocketAddress sockAddr, java.lang.Object message)
int	sendClient(java.net.InetSocketAddress sockAddr, java.lang.Object message, java.net.InetSocketAddress listenSocketAddress) A hack that relies on the fact that NIO treats JSONObject as no different from any other object in that it invokes toString() and then getBytes(.) to serialize and send it over the network.
int	sendToAddress(java.net.InetSocketAddress isa, byte[] msg)
int	sendToAddress(java.net.InetSocketAddress address, org.json.JSONObject jsonData) Sends jsonData to address.
int	sendToID(NodeIDType id, byte[] msg)
int	sendToID(NodeIDType id, org.json.JSONObject jsonData) Sends jsonData to node id.
void	setClientMessenger(AddressMessenger<?> clientMessenger)
void	setSSLClientMessenger(AddressMessenger<?> sslClientMessenger)
void	stop() Needs to be called to close NIO gracefully.
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

SENT_TIME

public static final java.lang.String SENT_TIME

The JSON key for the time when the message was sent. Used only for instrumentation purposes by AbstractPacketDemultiplexer.handleMessage

See Also:

Constant Field Values

execpool

protected final java.util.concurrent.ScheduledExecutorService execpool

Constructor Detail

JSONMessenger

public JSONMessenger(InterfaceNIOTransport<NodeIDType,org.json.JSONObject> niot)

Parameters:

niot -

JSONMessenger

public JSONMessenger(InterfaceNIOTransport<NodeIDType,org.json.JSONObject> niot,
                     int numWorkers)

Parameters:

niot -

numWorkers -

Method Detail

send

public void send(GenericMessagingTask<NodeIDType,?> mtask)
          throws java.io.IOException,
                 org.json.JSONException

Specified by:

send in interface Messenger<NodeIDType,org.json.JSONObject>

Throws:

java.io.IOException

org.json.JSONException

send

protected void send(GenericMessagingTask<NodeIDType,?> mtask,
                    boolean useWorkers)
             throws java.io.IOException,
                    org.json.JSONException

Send returns void because it is the "ultimate" send. It will retransmit if necessary. It is inconvenient for senders to worry about retransmission anyway. We may need to retransmit despite using TCP-based NIO because NIO is designed to be non-blocking, so it may sometimes drop messages when asked to send but the channel is congested. We use the return value of NIO send to decide whether to retransmit.

Throws:

java.io.IOException

org.json.JSONException

stop

public void stop()

Description copied from interface: InterfaceNIOTransport

Needs to be called to close NIO gracefully.

Specified by:

stop in interface InterfaceNIOTransport<NodeIDType,org.json.JSONObject>

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

sendToID

public int sendToID(NodeIDType id,
                    org.json.JSONObject jsonData)
             throws java.io.IOException

Sends jsonData to node id.

Specified by:

sendToID in interface InterfaceNIOTransport<NodeIDType,org.json.JSONObject>

Parameters:

id -

jsonData -

Returns:

Return value indicates the number of bytes sent. A value of -1 indicates an error.

Throws:

java.io.IOException

sendToAddress

public int sendToAddress(java.net.InetSocketAddress address,
                         org.json.JSONObject jsonData)
                  throws java.io.IOException

Sends jsonData to address.

Specified by:

sendToAddress in interface AddressMessenger<org.json.JSONObject>

Specified by:

sendToAddress in interface InterfaceNIOTransport<NodeIDType,org.json.JSONObject>

Parameters:

address -

jsonData -

Returns:

Refer sendToID(Object, JSONObject).

Throws:

java.io.IOException

getMyID

public NodeIDType getMyID()

Specified by:

getMyID in interface InterfaceNIOTransport<NodeIDType,org.json.JSONObject>

Returns:

My node ID.

addPacketDemultiplexer

public void addPacketDemultiplexer(AbstractPacketDemultiplexer<?> pd)

Specified by:

addPacketDemultiplexer in interface InterfaceNIOTransport<NodeIDType,org.json.JSONObject>

Parameters:

pd - The supplied packet demultiplexer is appended to end of the existing list. Messages will be processed by the first demultiplexer that has registered for processing the corresponding packet type and only by the first demultiplexer.

Note that there is no way to remove demultiplexers. All the necessary packet demultiplexers must be determined at design time. It is strongly recommended that all demultiplexers process exclusive sets of packet types. Relying on the order of chained demultiplexers is a bad idea.

precedePacketDemultiplexer

public void precedePacketDemultiplexer(AbstractPacketDemultiplexer<?> pd)

Specified by:

precedePacketDemultiplexer in interface InterfaceNIOTransport<NodeIDType,org.json.JSONObject>

Parameters:

pd - The demultiplexer is placed at the head of the existing list.

getNIOTransport

protected InterfaceNIOTransport<NodeIDType,org.json.JSONObject> getNIOTransport()

getClientMessenger

public AddressMessenger<org.json.JSONObject> getClientMessenger()

Specified by:

getClientMessenger in interface SSLMessenger<NodeIDType,org.json.JSONObject>

Returns:

Default client messenger if different from self.

getSSLClientMessenger

public AddressMessenger<org.json.JSONObject> getSSLClientMessenger()

Specified by:

getSSLClientMessenger in interface SSLMessenger<NodeIDType,org.json.JSONObject>

Returns:

Default client messenger if different from self.

setClientMessenger

public void setClientMessenger(AddressMessenger<?> clientMessenger)

Specified by:

setClientMessenger in interface SSLMessenger<NodeIDType,org.json.JSONObject>

setSSLClientMessenger

public void setSSLClientMessenger(AddressMessenger<?> sslClientMessenger)

Specified by:

setSSLClientMessenger in interface SSLMessenger<NodeIDType,org.json.JSONObject>

sendClient

public int sendClient(java.net.InetSocketAddress sockAddr,
                      java.lang.Object message,
                      java.net.InetSocketAddress listenSocketAddress)
               throws org.json.JSONException,
                      java.io.IOException

A hack that relies on the fact that NIO treats JSONObject as no different from any other object in that it invokes toString() and then getBytes(.) to serialize and send it over the network. It is necessary that the other end receiving this object be able to reconstruct it from a byte[], string, or JSONObject. Automatically tries to use clientMessenger.

Parameters:

sockAddr -

message -

listenSocketAddress -

Returns:

Number of bytes or characters written.

Throws:

org.json.JSONException

java.io.IOException

sendClient

public void sendClient(java.net.InetSocketAddress sockAddr,
                       java.lang.Object message)
                throws org.json.JSONException,
                       java.io.IOException

Parameters:

sockAddr -

message -

Throws:

org.json.JSONException

java.io.IOException

getNodeConfig

public NodeConfig<NodeIDType> getNodeConfig()

Specified by:

getNodeConfig in interface InterfaceNIOTransport<NodeIDType,org.json.JSONObject>

Returns:

Node config used by this NIO transport.

getSSLMode

public SSLDataProcessingWorker.SSL_MODES getSSLMode()

Specified by:

getSSLMode in interface InterfaceNIOTransport<NodeIDType,org.json.JSONObject>

Returns:

SSL mode used by this NIO transport.

sendToID

public int sendToID(NodeIDType id,
                    byte[] msg)
             throws java.io.IOException

Specified by:

sendToID in interface InterfaceNIOTransport<NodeIDType,org.json.JSONObject>

Returns:

Number of bytes written.

Throws:

java.io.IOException

sendToAddress

public int sendToAddress(java.net.InetSocketAddress isa,
                         byte[] msg)
                  throws java.io.IOException

Specified by:

sendToAddress in interface AddressMessenger<org.json.JSONObject>

Specified by:

sendToAddress in interface InterfaceNIOTransport<NodeIDType,org.json.JSONObject>

Returns:

Number of bytes written.

Throws:

java.io.IOException

isStopped

public boolean isStopped()

Specified by:

isStopped in interface InterfaceNIOTransport<NodeIDType,org.json.JSONObject>

Returns:

True if stopped.

isDisconnected

public boolean isDisconnected(NodeIDType node)

Specified by:

isDisconnected in interface InterfaceNIOTransport<NodeIDType,org.json.JSONObject>

Returns:

Whether node got disconnected.

getClientMessenger

public AddressMessenger<org.json.JSONObject> getClientMessenger(java.net.InetSocketAddress listenSockAddr)

Specified by:

getClientMessenger in interface SSLMessenger<NodeIDType,org.json.JSONObject>

Returns:

clientMessenger corresponding to (local) rcvSockAddr

getListeningSocketAddress

public java.net.InetSocketAddress getListeningSocketAddress()

Specified by:

getListeningSocketAddress in interface InterfaceNIOTransport<NodeIDType,org.json.JSONObject>

Returns:

Local socket address.