eu.hgross.blaubot.messaging

Class BlaubotChannel

java.lang.Object

eu.hgross.blaubot.messaging.BlaubotChannel

All Implemented Interfaces:

IBlaubotChannel

public class BlaubotChannel
extends java.lang.Object
implements IBlaubotChannel

A channel managed by the BlaubotChannelManager. Subscriptions to a channel can be made via subscribe() and removed by unsubscribe(). To listen to messages on this channel, attach a listener via {BlaubotChannel#addMessageListener}. Listeners can be removed via {BlaubotChannel#removeMessageListener}. Subscriptions are sent immediately to the network, meaning, that if there is no network, no subscription is made. The recommended way to subscribe to channels is to do this by a {ILifecycleListener#onConnected}. Messages send via {BlaubotChannel#publish} are added to a bounded queue, which is processed due to a defined message picking strategy (@see {IBlaubotMessagePickerStrategy}). The processing is activated/deactivated by the activate/deactivate methods. If activated, a processing thread uses the specified picker strategy to get messages from the queue and hands this messages to the BlaubotChannelManager. To influence the MessagePicking and message rates, @see {BlaubotChannel#getChannelConfig}. The picking and rates can be changed at runtime.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	BlaubotChannel(short channelId, BlaubotChannelManager channelManager)

Method Summary

Modifier and Type	Method and Description
protected void	activate() Activates the channel and therefore the message picking
void	addMessageListener(IBlaubotMessageListener messageListener) Add a message listener to this channel to get notifications when messages arrive.
protected void	addSubscription(java.lang.String uniqueDeviceID) Adds a subscription to uniqueDeviceId to this channel.
void	addSubscriptionListener(IBlaubotSubscriptionChangeListener subscriptionChangeListener) Adds a subscription listener to the manager
void	clearMessageQueue() Clears the message queue.
protected boolean	deactivate() Deactivates the channel and therefore the message picking.
BlaubotChannelConfig	getChannelConfig() The channel config specifying the message picking strategy and message rates as well as the id.
protected int	getQueueCapacity() The queue capacity
protected int	getQueueSize() The current amount of messages in the queue
long	getReceivedBytes() The amount of bytes received by this channel so far.
long	getReceivedMessages() The message count received by this channel so far.
long	getSentBytes() The amount of bytes sent through this channel so far.
long	getSentMessages() The message count sent through this channel so far.
protected java.util.concurrent.ConcurrentSkipListSet<java.lang.String>	getSubscriptions()
protected boolean	isActive()
protected void	notify(BlaubotMessage message) Notifies this channel about a new message.
boolean	publish(BlaubotMessage blaubotMessage) Posts a BlaubotMessage to the message queue of this channel to be dispatched to subscribers later.
boolean	publish(BlaubotMessage blaubotMessage, boolean excludeSender) Posts a BlaubotMessage to the message queue of this channel to be dispatched to subscribers later.
boolean	publish(BlaubotMessage blaubotMessage, long timeout) Posts a BlaubotMessage to the message queue of this channel to be dispatched to subscribers later.
boolean	publish(BlaubotMessage blaubotMessage, long timeout, boolean excludeSender) Posts a BlaubotMessage to the message queue of this channel to be dispatched to subscribers later.
boolean	publish(byte[] payload) Post the payload to this channel's queue.
boolean	publish(byte[] payload, boolean excludeSender) Post the payload to this channel's queue.
boolean	publish(byte[] payload, long timeout) Post the payload to this channel's queue.
boolean	publish(byte[] payload, long timeout, boolean excludeSender) Post the payload to this channel's queue.
void	removeMessageListener(IBlaubotMessageListener messageListener) Removes a previously added message listener from this channel If after the operation no listener is attached to this channel anymore, unsubscribe() is called automatically.
protected void	removeSubscription(java.lang.String uniqueDeviceId) Removes the subscription of uniqueDeviceId to this channel The operation is idempotent.
void	removeSubscriptionListener(IBlaubotSubscriptionChangeListener subscriptionChangeListener) Removes a subscription listener from the manager
protected int	sendAddSubscription(java.lang.String uniqueDeviceID) Sends the AddSubscriptionMessage to the master.
protected int	sendRemoveSubscription(java.lang.String uniqueDeviceId) Sends the RemoveSubscriptionMessage to the master.
protected void	setDoNotTransmit(boolean doNotTransmit) Allows or disallows transmission of messages by this channel.
void	subscribe() Subscribes to the channel
void	subscribe(IBlaubotMessageListener blaubotMessageListener) Subscribes to this channel and attaches a message listener
void	unsubscribe() Remove the subscription of this channel

Methods inherited from class java.lang.Object

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

Constructor Detail

BlaubotChannel

protected BlaubotChannel(short channelId,
                         BlaubotChannelManager channelManager)

Parameters:

channelId - the channel id

channelManager - the channelManager instance, that created this channel

Method Detail

publish

public boolean publish(BlaubotMessage blaubotMessage)

Description copied from interface: IBlaubotChannel

Posts a BlaubotMessage to the message queue of this channel to be dispatched to subscribers later.

Specified by:

publish in interface IBlaubotChannel

Parameters:

blaubotMessage - the message

Returns:

true, iff the message was added to the queue or false, if the queue was full while trying to publish

publish

public boolean publish(BlaubotMessage blaubotMessage,
                       boolean excludeSender)

Description copied from interface: IBlaubotChannel

Posts a BlaubotMessage to the message queue of this channel to be dispatched to subscribers later. Will block, if the channel's message queue is full.

Specified by:

publish in interface IBlaubotChannel

Parameters:

blaubotMessage - the message

excludeSender - if true, the message will not be dispatched back to this channel but to all other subscribers.

Returns:

true, iff the message was added to the queue or false, if the queue was full while trying to publish

publish

public boolean publish(BlaubotMessage blaubotMessage,
                       long timeout)

Description copied from interface: IBlaubotChannel

Posts a BlaubotMessage to the message queue of this channel to be dispatched to subscribers later. Blocks for 'timeout' milliseconds, if the channel's message queue is full.

Specified by:

publish in interface IBlaubotChannel

Parameters:

blaubotMessage - the mssage

timeout - the timeout in ms

Returns:

true, iff the message was added to the queue or false, if the timeout elapsed before

publish

public boolean publish(BlaubotMessage blaubotMessage,
                       long timeout,
                       boolean excludeSender)

Description copied from interface: IBlaubotChannel

Posts a BlaubotMessage to the message queue of this channel to be dispatched to subscribers later. Blocks for 'timeout' milliseconds, if the channel's message queue is full.

Specified by:

publish in interface IBlaubotChannel

Parameters:

blaubotMessage - the mssage

timeout - the timeout in ms

excludeSender - if true, the message will not be dispatched back to this channel but to all other subscribers.

Returns:

true, iff the message was added to the queue or false, if the timeout elapsed before

publish

public boolean publish(byte[] payload)

Description copied from interface: IBlaubotChannel

Post the payload to this channel's queue. The payload will be wrapped in a BlaubotMessage.

Specified by:

publish in interface IBlaubotChannel

Parameters:

payload - the payload as byte array

Returns:

true, iff the message was added to the queue or false, if the queue was full while trying to publish

publish

public boolean publish(byte[] payload,
                       boolean excludeSender)

Description copied from interface: IBlaubotChannel

Post the payload to this channel's queue. The payload will be wrapped in a BlaubotMessage.

Specified by:

publish in interface IBlaubotChannel

Parameters:

payload - the payload as byte array

excludeSender - if true, the message will not be dispatched back to this channel but to all other subscribers.

Returns:

true, iff the message was added to the queue or false, if the queue was full while trying to publish

publish

public boolean publish(byte[] payload,
                       long timeout)

Description copied from interface: IBlaubotChannel

Post the payload to this channel's queue. The payload will be wrapped in a BlaubotMessage. Blocks for 'timeout' milliseconds, if the channel's message queue is full.

Specified by:

publish in interface IBlaubotChannel

Parameters:

payload - the payload as byte array

timeout - the timeout in ms

Returns:

true, iff the message was added to the queue or false, if the timeout elapsed before

publish

public boolean publish(byte[] payload,
                       long timeout,
                       boolean excludeSender)

Description copied from interface: IBlaubotChannel

Post the payload to this channel's queue. The payload will be wrapped in a BlaubotMessage. Blocks for 'timeout' milliseconds, if the channel's message queue is full.

Specified by:

publish in interface IBlaubotChannel

Parameters:

payload - the payload as byte array

timeout - the timeout in ms

excludeSender - if true, the message will not be dispatched back to this channel but to all other subscribers.

Returns:

true, iff the message was added to the queue or false, if the timeout elapsed before

subscribe

public void subscribe()

Description copied from interface: IBlaubotChannel

Subscribes to the channel

Specified by:

subscribe in interface IBlaubotChannel

subscribe

public void subscribe(IBlaubotMessageListener blaubotMessageListener)

Description copied from interface: IBlaubotChannel

Subscribes to this channel and attaches a message listener

Specified by:

subscribe in interface IBlaubotChannel

Parameters:

blaubotMessageListener - the listener to be informed about new messages on this channel

unsubscribe

public void unsubscribe()

Description copied from interface: IBlaubotChannel

Remove the subscription of this channel

Specified by:

unsubscribe in interface IBlaubotChannel

addMessageListener

public void addMessageListener(IBlaubotMessageListener messageListener)

Description copied from interface: IBlaubotChannel

Add a message listener to this channel to get notifications when messages arrive. Note that this method does not subscribe automatically subscribe to the channel. Call subscribe() if you want to get messages dispatched to this channel.

Specified by:

addMessageListener in interface IBlaubotChannel

Parameters:

messageListener - the message listener to add

removeMessageListener

public void removeMessageListener(IBlaubotMessageListener messageListener)

Description copied from interface: IBlaubotChannel

Removes a previously added message listener from this channel If after the operation no listener is attached to this channel anymore, unsubscribe() is called automatically.

Specified by:

removeMessageListener in interface IBlaubotChannel

Parameters:

messageListener - the listener to remove

sendAddSubscription

protected int sendAddSubscription(java.lang.String uniqueDeviceID)

Sends the AddSubscriptionMessage to the master. The Subscription itself is added, when the master sends the message back and addSubscription is called by the ChannelManager

Parameters:

uniqueDeviceID - the unique

Returns:

number of MessageManagers to which the message was committed

sendRemoveSubscription

protected int sendRemoveSubscription(java.lang.String uniqueDeviceId)

Sends the RemoveSubscriptionMessage to the master. The subscription itsef is removed, when the master sends the message back and removeSubscription gets called by the ChannelManager.

Parameters:

uniqueDeviceId - the unique device id

Returns:

number of MessageManagers to which the message was committed

addSubscription

protected void addSubscription(java.lang.String uniqueDeviceID)

Adds a subscription to uniqueDeviceId to this channel. The operation is idempotent.

Parameters:

uniqueDeviceID - the unique device id of the device that will be a new subscriber

removeSubscription

protected void removeSubscription(java.lang.String uniqueDeviceId)

Removes the subscription of uniqueDeviceId to this channel The operation is idempotent.

Parameters:

uniqueDeviceId - the unique device id of the device that will be unsubscribed

getSubscriptions

protected java.util.concurrent.ConcurrentSkipListSet<java.lang.String> getSubscriptions()

notify

protected void notify(BlaubotMessage message)

Notifies this channel about a new message. Gets called from the outside (BlaubotChannelManager.messageDispatcher).

Parameters:

message - the message posted to this channel

getChannelConfig

public BlaubotChannelConfig getChannelConfig()

The channel config specifying the message picking strategy and message rates as well as the id. The config's values can be changed at runtime. Changes are only reflected, if the channel is activated, meaning the net ChannelManager is activated or respectively we are connected to a blaubot network.

Specified by:

getChannelConfig in interface IBlaubotChannel

Returns:

the channel config

clearMessageQueue

public void clearMessageQueue()

Description copied from interface: IBlaubotChannel

Clears the message queue. Useful in situations when the blaubot instance gets disconnected and there are still unsent messages in the queue.

Specified by:

clearMessageQueue in interface IBlaubotChannel

addSubscriptionListener

public void addSubscriptionListener(IBlaubotSubscriptionChangeListener subscriptionChangeListener)

Adds a subscription listener to the manager

Parameters:

subscriptionChangeListener - the listener to add

removeSubscriptionListener

public void removeSubscriptionListener(IBlaubotSubscriptionChangeListener subscriptionChangeListener)

Removes a subscription listener from the manager

Parameters:

subscriptionChangeListener - the listener to remove

activate

protected void activate()

Activates the channel and therefore the message picking

deactivate

protected boolean deactivate()

Deactivates the channel and therefore the message picking. Blocks until the channel has shut down!

Returns:

true, iff the channel was activated before

isActive

protected boolean isActive()

Returns:

true, iff active (= executor started)

getQueueCapacity

protected int getQueueCapacity()

The queue capacity

Returns:

capacity of the queue

getQueueSize

protected int getQueueSize()

The current amount of messages in the queue

Returns:

current amount of messages in the queue

getSentBytes

public long getSentBytes()

The amount of bytes sent through this channel so far.

Returns:

number of bytes

getSentMessages

public long getSentMessages()

The message count sent through this channel so far.

Returns:

number of messages

getReceivedMessages

public long getReceivedMessages()

The message count received by this channel so far.

Returns:

number of messages

getReceivedBytes

public long getReceivedBytes()

The amount of bytes received by this channel so far.

Returns:

number of bytes

setDoNotTransmit

protected void setDoNotTransmit(boolean doNotTransmit)

Allows or disallows transmission of messages by this channel. Is used to block picking as long as an initial subscription handshake is pending.

Parameters:

doNotTransmit - if true, no messages will be picked as long as this state is set