org.xmlBlaster.util.dispatch.plugins.prio
Class PriorizedDispatchPlugin

java.lang.Object
  org.xmlBlaster.util.dispatch.plugins.prio.PriorizedDispatchPlugin

All Implemented Interfaces:

I_ConnectionStatusListener, I_MsgDispatchInterceptor, I_Notify, I_Plugin, I_PropertyChangeListener

public final class PriorizedDispatchPlugin

extends java.lang.Object

implements I_MsgDispatchInterceptor, I_Plugin, I_PropertyChangeListener, I_Notify

This dispatcher plugin allows to control how messages are sent to the remote side.

We subscribe to a status message which describes the current connection to the remote side. Depending on a status message we pick messages with specific priorities and send only these.

This allows for example to send all messages if a 2MBit connection is up, and send only high priority messages when the line drops to 64kBit.

The class ConfigurationParser Javadoc has an xml example of the configuration

This plugin class has only one instance per typeVersion for each Global scope. The xmlBlaster client used to subscribe to the status messages is a singleton (in Global.instance() scope).

Note that two status sources exist:

1. The state of the connection of the dispatcher framework, it may for example be POLLING for a remote connection or have an ALIVE state or even be in DEAD state. If a configuration is found for this state it has highest precedence.
2. The status of a status message from outside. This is freely configurable and is for example 2M or BACKUP. This status message has lower precedence.

Author:

xmlBlaster@marcelruff.info

See Also:

ConfigurationParser, TestPriorizedDispatchPlugin, the dispatch.control.plugin requirement

Field Summary

static java.lang.String	CONFIG_PROPERTY_KEY
private java.lang.String	currMsgStatus
private StatusConfiguration	currMsgStatusConfiguration This is the configuration for the current status of the last received status message:
private java.util.Map	dispatchManagerEntryMap
private Global	glob
private boolean	hasDefaultActionOnly
private boolean	hasSpecificConf
private boolean	isShutdown
private static java.util.logging.Logger	log
private java.lang.String	ME
private ConfigurationParser	parser
DispatchAction	QUEUE_ACTION
private java.lang.String	specificConfigPropertyKey
private XmlBlasterNativeClient	xmlBlasterClient

Constructor Summary

PriorizedDispatchPlugin()

Method Summary

void	addDispatchManager(DispatchManager dispatchManager) This is called once for each dispatch manager using this plugin.
private DispatchManagerEntry	changeManagerState(DispatchManager dispatchManager, ConnectionStateEnum newState, boolean flush)
boolean	doActivate(DispatchManager dispatchManager) Called when new messages are available.
private void	flushHoldbackQueue(DispatchManagerEntry managerEntry) All entries from our holdback queue are flushed to the official queues of the DispatchManager
private DispatchAction	getDispatchAction(DispatchManagerEntry managerEntry, MsgQueueEntry entry) Lookup the corresponding DispatchAction object this message priority.
private DispatchManagerEntry	getDispatchManagerEntry(DispatchManager dispatchManager)
private DispatchManagerEntry[]	getDispatchManagerEntryArr()
java.lang.String	getType() Enforced by I_Plugin
java.lang.String	getVersion() Enforced by I_Plugin
java.util.ArrayList	handleNextMessages(DispatchManager dispatchManager, java.util.ArrayList entries) Enforced by I_MsgDispatchInterceptor.
void	init(Global glob, PluginInfo pluginInfo) Enforced by I_Plugin
void	initialize(Global glob, java.lang.String typeVersion) Is called by DispatchPluginManager after the instance is created.
boolean	isShutdown()
void	onDispatchWorkerException(DispatchManager dispatchManager, java.lang.Throwable ex) Not doing anything in this method since no Exception handling is done.
void	postHandleNextMessages(DispatchManager dispatchManager, MsgUnit[] processedEntries) Not doing anything in this method since no cleanup needed.
void	propertyChanged(PropertyChangeEvent ev) Invoked when the configuration PriorizedDispatchPlugin/config has changed.
private void	putToHoldbackQueue(DispatchManagerEntry managerEntry, MsgQueueEntry entry)
void	shutdown() Shutdown the implementation, sync with data store
void	shutdown(DispatchManager dispatchManager) Deregister a dispatch manager.
void	statusChanged(java.lang.String status) Changing the status of the dispatch strategy.
private void	subscribeStatusMessages() Subscribe to messages according to the current configuration.
void	toAlive(DispatchManager dispatchManager, ConnectionStateEnum oldState) Call by DispatchConnectionsHandler on state transition.
void	toDead(DispatchManager dispatchManager, ConnectionStateEnum oldState, java.lang.String errorText) Call by DispatchConnectionsHandler on state transition Enforced by interface I_ConnectionStatusListener
void	toPolling(DispatchManager dispatchManager, ConnectionStateEnum oldState) Call by DispatchConnectionsHandler on state transition Enforced by interface I_ConnectionStatusListener
java.lang.String	toXml(java.lang.String extraOffset)
java.lang.String	usage()

Methods inherited from class java.lang.Object

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

Field Detail

ME

private java.lang.String ME

glob

private Global glob

log

private static java.util.logging.Logger log

parser

private ConfigurationParser parser

CONFIG_PROPERTY_KEY

public static final java.lang.String CONFIG_PROPERTY_KEY

See Also:

Constant Field Values

specificConfigPropertyKey

private java.lang.String specificConfigPropertyKey

hasSpecificConf

private boolean hasSpecificConf

currMsgStatusConfiguration

private StatusConfiguration currMsgStatusConfiguration

This is the configuration for the current status of the last received status message:

currMsgStatus

private java.lang.String currMsgStatus

hasDefaultActionOnly

private boolean hasDefaultActionOnly

xmlBlasterClient

private XmlBlasterNativeClient xmlBlasterClient

dispatchManagerEntryMap

private java.util.Map dispatchManagerEntryMap

isShutdown

private boolean isShutdown

QUEUE_ACTION

public DispatchAction QUEUE_ACTION

Constructor Detail

PriorizedDispatchPlugin

public PriorizedDispatchPlugin()

Method Detail

initialize

public void initialize(Global glob,
                       java.lang.String typeVersion)
                throws XmlBlasterException

Is called by DispatchPluginManager after the instance is created.

Specified by:

initialize in interface I_MsgDispatchInterceptor

Throws:

XmlBlasterException

See Also:

I_MsgDispatchInterceptor.initialize(Global, String)

addDispatchManager

public void addDispatchManager(DispatchManager dispatchManager)

This is called once for each dispatch manager using this plugin.

Specified by:

addDispatchManager in interface I_MsgDispatchInterceptor

propertyChanged

public void propertyChanged(PropertyChangeEvent ev)

Invoked when the configuration PriorizedDispatchPlugin/config has changed. Supports changing configuration in hot operation.

Specified by:

propertyChanged in interface I_PropertyChangeListener

subscribeStatusMessages

private void subscribeStatusMessages()
                              throws XmlBlasterException

Subscribe to messages according to the current configuration.

Throws:

XmlBlasterException

init

public void init(Global glob,
                 PluginInfo pluginInfo)

Enforced by I_Plugin

Specified by:

init in interface I_Plugin

See Also:

I_Plugin.init(org.xmlBlaster.util.Global, PluginInfo)

getType

public java.lang.String getType()

Enforced by I_Plugin

Specified by:

getType in interface I_Plugin

Returns:

"Priority"

getVersion

public final java.lang.String getVersion()

Enforced by I_Plugin

Specified by:

getVersion in interface I_Plugin

Returns:

"1.0"

statusChanged

public final void statusChanged(java.lang.String status)

Changing the status of the dispatch strategy.

Enforced by I_Notify

On initialize: addPropertyChangeListener(this.CONFIG_PROPERTY_KEY, "startup", this); an initial event is fired an calls this method to initialize all attributes here

Specified by:

statusChanged in interface I_Notify

getDispatchAction

private final DispatchAction getDispatchAction(DispatchManagerEntry managerEntry,
                                               MsgQueueEntry entry)

Lookup the corresponding DispatchAction object this message priority.

doActivate

public final boolean doActivate(DispatchManager dispatchManager)

Called when new messages are available.

Specified by:

doActivate in interface I_MsgDispatchInterceptor

Returns:

true: create a worker thread to process messages from queue (it will call our getNextMessages() method where we can decide which messages it will process
false: abort, don't start worker thread

See Also:

I_MsgDispatchInterceptor.doActivate(DispatchManager)

handleNextMessages

public final java.util.ArrayList handleNextMessages(DispatchManager dispatchManager,
                                                    java.util.ArrayList entries)
                                             throws XmlBlasterException

Enforced by I_MsgDispatchInterceptor.

NOTE: When copying entries from one queue to another one we have to take care that the reference counter in msgUnitStore is not temporary zero (and is garbage collected). This is avoided by a peek() and later remove() - which is necessary for persistent messages anyhow to ensure 100% crash safety.

Specified by:

handleNextMessages in interface I_MsgDispatchInterceptor

Parameters:

entries - null: Take messages yourself from queue (async mode)
not null: Use messages pushed (sync mode) or messages from ErrorCode.COMMUNICATION*

Returns:

An ArrayList containing the I_QueueEntry to send.
If list.size() == 0 the worker thread stops and does nothing
If list.size() > 0 the given messages are sent. In case of pushEntries>0 and ErrorCode.COMMUNICATION* if you return them they are send to error handler.

Throws:

XmlBlasterException

See Also:

I_MsgDispatchInterceptor.handleNextMessages(DispatchManager, ArrayList)

getDispatchManagerEntry

private DispatchManagerEntry getDispatchManagerEntry(DispatchManager dispatchManager)

putToHoldbackQueue

private void putToHoldbackQueue(DispatchManagerEntry managerEntry,
                                MsgQueueEntry entry)
                         throws XmlBlasterException

Throws:

XmlBlasterException

flushHoldbackQueue

private void flushHoldbackQueue(DispatchManagerEntry managerEntry)

All entries from our holdback queue are flushed to the official queues of the DispatchManager

toAlive

public final void toAlive(DispatchManager dispatchManager,
                          ConnectionStateEnum oldState)

Call by DispatchConnectionsHandler on state transition.

Enforced by interface I_ConnectionStatusListener

Specified by:

toAlive in interface I_ConnectionStatusListener

toPolling

public final void toPolling(DispatchManager dispatchManager,
                            ConnectionStateEnum oldState)

Call by DispatchConnectionsHandler on state transition

Enforced by interface I_ConnectionStatusListener

Specified by:

toPolling in interface I_ConnectionStatusListener

toDead

public final void toDead(DispatchManager dispatchManager,
                         ConnectionStateEnum oldState,
                         java.lang.String errorText)

Call by DispatchConnectionsHandler on state transition

Enforced by interface I_ConnectionStatusListener

Specified by:

toDead in interface I_ConnectionStatusListener

changeManagerState

private DispatchManagerEntry changeManagerState(DispatchManager dispatchManager,
                                                ConnectionStateEnum newState,
                                                boolean flush)

getDispatchManagerEntryArr

private DispatchManagerEntry[] getDispatchManagerEntryArr()

Returns:

A current snapshot (thread save etc)

shutdown

public void shutdown(DispatchManager dispatchManager)
              throws XmlBlasterException

Deregister a dispatch manager.

Specified by:

shutdown in interface I_MsgDispatchInterceptor

Throws:

XmlBlasterException

See Also:

I_MsgDispatchInterceptor.shutdown(DispatchManager)

shutdown

public void shutdown()
              throws XmlBlasterException

Description copied from interface: I_MsgDispatchInterceptor

Shutdown the implementation, sync with data store

Specified by:

shutdown in interface I_MsgDispatchInterceptor

Throws:

XmlBlasterException

isShutdown

public boolean isShutdown()

Specified by:

isShutdown in interface I_MsgDispatchInterceptor

Returns:

true if shutdown

usage

public java.lang.String usage()

Specified by:

usage in interface I_MsgDispatchInterceptor

Returns:

a human readable usage help string

toXml

public java.lang.String toXml(java.lang.String extraOffset)

Specified by:

toXml in interface I_MsgDispatchInterceptor

Parameters:

extraOffset - Indent the dump with given ASCII blanks

Returns:

An xml encoded dump

See Also:

I_MsgDispatchInterceptor.toXml(String)

postHandleNextMessages

public void postHandleNextMessages(DispatchManager dispatchManager,
                                   MsgUnit[] processedEntries)
                            throws XmlBlasterException

Not doing anything in this method since no cleanup needed.

Specified by:

postHandleNextMessages in interface I_MsgDispatchInterceptor

Parameters:

dispatchManager - The used dispatch manager.

processedEntries - The entries which have been previously processed.

Throws:

XmlBlasterException

onDispatchWorkerException

public void onDispatchWorkerException(DispatchManager dispatchManager,
                                      java.lang.Throwable ex)

Not doing anything in this method since no Exception handling is done.

Specified by:

onDispatchWorkerException in interface I_MsgDispatchInterceptor

Parameters:

dispatchManager -

ex -