org.jgroups.protocols

Class STOMP

java.lang.Object

org.jgroups.stack.Protocol

org.jgroups.protocols.STOMP

All Implemented Interfaces:

java.lang.Runnable

public class STOMP
extends Protocol
implements java.lang.Runnable

Protocol which provides STOMP (http://stomp.codehaus.org/) support. Very simple implementation, with a one-thread-per-connection model. Use for a few hundred clients max.

The intended use for this protocol is pub-sub with clients which handle text messages, e.g. stock updates, SMS messages to mobile clients, SNMP traps etc.

Note that the full STOMP protocol has not yet been implemented, e.g. transactions are not supported. todo: use a thread pool to handle incoming frames and to send messages to clients

todo: add PING to test health of client connections

Since:

2.11

Author:

Bela Ban

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	STOMP.ClientVerb
class	STOMP.Connection Class which handles a connection to a client
static class	STOMP.Frame
static class	STOMP.ServerVerb
static class	STOMP.StompHeader

Field Summary

Fields

Modifier and Type	Field and Description
protected java.lang.Thread	acceptor
protected java.net.InetAddress	bind_addr
protected java.util.List<STOMP.Connection>	connections
protected java.lang.String	endpoint
protected java.lang.String	endpoint_addr
protected java.util.Map<Address,java.lang.String>	endpoints
protected boolean	exact_destination_match
protected boolean	forward_non_client_generated_msgs
protected Address	local_addr
static byte	NULL_BYTE
protected int	port
protected boolean	send_info
protected java.net.ServerSocket	srv_sock
protected java.util.concurrent.ConcurrentMap<java.lang.String,java.util.Set<STOMP.Connection>>	subscriptions
protected View	view

Fields inherited from class org.jgroups.stack.Protocol

after_creation_hook, down_prot, ergonomics, id, log, name, stack, stats, up_prot

Constructor Summary

Constructors

Constructor and Description
STOMP()

Method Summary

Modifier and Type	Method and Description
protected void	broadcastEndpoint()
java.lang.Object	down(Event evt) An event is to be sent down the stack.
protected java.lang.String	getAllEndpoints()
java.lang.String	getEndpoints()
int	getNumConnections()
int	getNumSubscriptions()
java.lang.String	getSubscriptions()
protected void	handleView(View view)
static STOMP.Frame	readFrame(java.io.DataInputStream in)
void	run()
void	start() This method is called on a Channel.connect(String).
void	stop() This method is called on a Channel.disconnect().
java.lang.Object	up(Event evt) An event was received from the layer below.
void	up(MessageBatch batch) Sends up a multiple messages in a MessageBatch.

Methods inherited from class org.jgroups.stack.Protocol

accept, afterCreationHook, destroy, dumpStats, enableStats, getConfigurableObjects, getDownProtocol, getDownServices, getId, getIdsAbove, getLevel, getLog, getName, getProtocolStack, getSocketFactory, getThreadFactory, getTransport, getUpProtocol, getUpServices, getValue, init, isErgonomics, level, parse, printStats, providedDownServices, providedUpServices, requiredDownServices, requiredUpServices, resetStatistics, resetStats, setDownProtocol, setErgonomics, setId, setLevel, setProtocolStack, setSocketFactory, setUpProtocol, setValue, setValues, statsEnabled

Methods inherited from class java.lang.Object

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

Field Detail

bind_addr

protected java.net.InetAddress bind_addr

endpoint_addr

protected java.lang.String endpoint_addr

port

protected int port

exact_destination_match

protected boolean exact_destination_match

send_info

protected boolean send_info

forward_non_client_generated_msgs

protected boolean forward_non_client_generated_msgs

local_addr

protected Address local_addr

srv_sock

protected java.net.ServerSocket srv_sock

endpoint

protected java.lang.String endpoint

acceptor

protected java.lang.Thread acceptor

connections

protected final java.util.List<STOMP.Connection> connections

endpoints

protected final java.util.Map<Address,java.lang.String> endpoints

view

protected View view

subscriptions

protected final java.util.concurrent.ConcurrentMap<java.lang.String,java.util.Set<STOMP.Connection>> subscriptions

NULL_BYTE

public static final byte NULL_BYTE

See Also:

Constant Field Values

Constructor Detail

STOMP

public STOMP()

Method Detail

getNumConnections

public int getNumConnections()

getNumSubscriptions

public int getNumSubscriptions()

getSubscriptions

public java.lang.String getSubscriptions()

getEndpoints

public java.lang.String getEndpoints()

start

public void start()
           throws java.lang.Exception

Description copied from class: Protocol

This method is called on a Channel.connect(String). Starts work. Protocols are connected and queues are ready to receive events. Will be called from bottom to top. This call will replace the START and START_OK events.

Overrides:

start in class Protocol

Throws:

java.lang.Exception - Thrown if protocol cannot be started successfully. This will cause the ProtocolStack to fail, so Channel.connect(String) will throw an exception

stop

public void stop()

Description copied from class: Protocol

This method is called on a Channel.disconnect(). Stops work (e.g. by closing multicast socket). Will be called from top to bottom. This means that at the time of the method invocation the neighbor protocol below is still working. This method will replace the STOP, STOP_OK, CLEANUP and CLEANUP_OK events. The ProtocolStack guarantees that when this method is called all messages in the down queue will have been flushed

Overrides:

stop in class Protocol

run

public void run()

Specified by:

run in interface java.lang.Runnable

down

public java.lang.Object down(Event evt)

Description copied from class: Protocol

An event is to be sent down the stack. The layer may want to examine its type and perform some action on it, depending on the event's type. If the event is a message MSG, then the layer may need to add a header to it (or do nothing at all) before sending it down the stack using down_prot.down(). In case of a GET_ADDRESS event (which tries to retrieve the stack's address from one of the bottom layers), the layer may need to send a new response event back up the stack using up_prot.up().

Overrides:

down in class Protocol

up

public java.lang.Object up(Event evt)

Description copied from class: Protocol

An event was received from the layer below. Usually the current layer will want to examine the event type and - depending on its type - perform some computation (e.g. removing headers from a MSG event type, or updating the internal membership list when receiving a VIEW_CHANGE event). Finally the event is either a) discarded, or b) an event is sent down the stack using down_prot.down() or c) the event (or another event) is sent up the stack using up_prot.up().

Overrides:

up in class Protocol

up

public void up(MessageBatch batch)

Description copied from class: Protocol

Sends up a multiple messages in a MessageBatch. The sender of the batch is always the same, and so is the destination (null == multicast messages). Messages in a batch can be OOB messages, regular messages, or mixed messages, although the transport itself will create initial MessageBatches that contain only either OOB or regular messages.

The default processing below sends messages up the stack individually, based on a matching criteria (calling Protocol.accept(org.jgroups.Message)), and - if true - calls Protocol.up(org.jgroups.Event) for that message and removes the message. If the batch is not empty, it is passed up, or else it is dropped.

Subclasses should check if there are any messages destined for them (e.g. using MessageBatch.getMatchingMessages(short,boolean)), then possibly remove and process them and finally pass the batch up to the next protocol. Protocols can also modify messages in place, e.g. ENCRYPT could decrypt all encrypted messages in the batch, not remove them, and pass the batch up when done.

Overrides:

up in class Protocol

Parameters:

batch - The message batch

readFrame

public static STOMP.Frame readFrame(java.io.DataInputStream in)
                             throws java.io.IOException

Throws:

java.io.IOException

handleView

protected void handleView(View view)

getAllEndpoints

protected java.lang.String getAllEndpoints()

broadcastEndpoint

protected void broadcastEndpoint()