org.xmlBlaster.contrib
Class MomEventEngine

java.lang.Object
  org.xmlBlaster.contrib.MomEventEngine

All Implemented Interfaces:

java.util.EventListener, I_Callback, I_ChangePublisher, I_ContribPlugin

public class MomEventEngine
extends java.lang.Object
implements I_Callback, I_ChangePublisher

Field Summary

private int	compressSize
protected I_XmlBlasterAccess	con
protected ConnectQos	connectQos
protected I_Update	eventHandler
protected Global	glob
private static java.util.logging.Logger	log
protected java.lang.String	loginName
protected java.lang.String	password
protected boolean	shutdownMom
protected java.util.List	subscribeKeyList
protected java.util.List	subscribeQosList

Constructor Summary

MomEventEngine()

Method Summary

static byte[]	compress(byte[] buffer, java.util.Map props, int compressSizeLimit, java.lang.String zipType) Compresses the message if needed.
static byte[]	compressOLD(byte[] buffer, java.util.Map props, int compressSizeLimit, java.lang.String zipType) Deprecated.
static java.io.InputStream	decompress(java.io.InputStream is, java.util.Map clientProperties)
static byte[]	decompressXX(byte[] buffer, java.util.Map clientProperties) Deprecated. you should use the one with InputStream instead since less memory hungry (for big messages)
private static java.lang.String	dumpProps(java.util.Map clientProperties)
XBSession	getJmsSession() Only used in replication, can return null if not used.
java.util.Set	getUsedPropertyKeys() Gets all property keys which may be used by this object.
void	init(I_Info info) After creation this method is called.
java.lang.String	publish(java.lang.String oid, byte[] message, java.util.Map attrMap) Send the message to the MoM.
boolean	registerAlertListener(I_Update update, java.util.Map attrs) Register for alerts when the data source has changed.
void	shutdown() Cleanup resources.
java.lang.String	update(java.lang.String cbSessionId, UpdateKey updateKey, byte[] content, UpdateQos updateQos) This is the callback method invoked from I_XmlBlasterAccess informing the client in an asynchronous mode about a new message.

Methods inherited from class java.lang.Object

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

Field Detail

log

private static java.util.logging.Logger log

glob

protected Global glob

con

protected I_XmlBlasterAccess con

loginName

protected java.lang.String loginName

password

protected java.lang.String password

subscribeKeyList

protected java.util.List subscribeKeyList

subscribeQosList

protected java.util.List subscribeQosList

connectQos

protected ConnectQos connectQos

eventHandler

protected I_Update eventHandler

shutdownMom

protected boolean shutdownMom

compressSize

private int compressSize

Constructor Detail

MomEventEngine

public MomEventEngine()

Method Detail

getUsedPropertyKeys

public java.util.Set getUsedPropertyKeys()

Description copied from interface: I_ContribPlugin

Gets all property keys which may be used by this object.

Specified by:

getUsedPropertyKeys in interface I_ContribPlugin

Returns:

See Also:

I_ContribPlugin.getUsedPropertyKeys()

init

public void init(I_Info info)
          throws java.lang.Exception

Description copied from interface: I_ChangePublisher

After creation this method is called. The plugin must register itself into global scope with info.setObject("org.xmlBlaster.contrib.dbwatcher.mom.I_ChangePublisher", this) to be available for others.

Specified by:

init in interface I_ChangePublisher

Specified by:

init in interface I_ContribPlugin

Parameters:

info - The configuration environment

Throws:

java.lang.Exception - MoM specific

update

public java.lang.String update(java.lang.String cbSessionId,
                               UpdateKey updateKey,
                               byte[] content,
                               UpdateQos updateQos)
                        throws XmlBlasterException

Description copied from interface: I_Callback

This is the callback method invoked from I_XmlBlasterAccess informing the client in an asynchronous mode about a new message.

So you should implement in your client code the I_Callback interface - suppling the update() method where you can do with the message whatever you want.

The raw protocol driver specific update() method (e.g. CORBA-BlasterCallback.update()) is unpacked and for each arrived message this update is called.

Specified by:

update in interface I_Callback

Parameters:

cbSessionId - The session ID specified by the client which registered the callback. You can specify a cbSessionId during connection (with ConnectQos) and this is bounced back here so you can authenticate the message.

updateKey - The arrived key containing the topic name

content - The arrived message content. This is your payload.

Throws:

XmlBlasterException

See Also:

I_XmlBlasterAccess

publish

public java.lang.String publish(java.lang.String oid,
                                byte[] message,
                                java.util.Map attrMap)
                         throws java.lang.Exception

Description copied from interface: I_ChangePublisher

Send the message to the MoM.

Specified by:

publish in interface I_ChangePublisher

Parameters:

changeKey - The topic of the message as a string.

message - the content of the message to publish.

Returns:

the PublishQos as a string.

Throws:

java.lang.Exception - On sending problems

registerAlertListener

public boolean registerAlertListener(I_Update update,
                                     java.util.Map attrs)
                              throws java.lang.Exception

Description copied from interface: I_ChangePublisher

Register for alerts when the data source has changed.

This funtionality is plugin depending, for example the xmlBlaster plugin has a configuration option to subscribe on a alert topic and listens if somebody publishes a message to it. If such a message arrives we trigger a new database poll.

Specified by:

registerAlertListener in interface I_ChangePublisher

Parameters:

update - The callback interface to receive the notification

attrs - extra parameters to pass for the registration. For example if one implementation wants to do a specific extra subscription it would pass the quality of service in the attributes.

Returns:

true if a notification is available (is configured)

Throws:

java.lang.Exception - The MoM specific exception

shutdown

public void shutdown()

Description copied from interface: I_ChangePublisher

Cleanup resources.

Can be called multiple times if instance is reused from different plugins.

Specified by:

shutdown in interface I_ChangePublisher

Specified by:

shutdown in interface I_ContribPlugin

See Also:

I_Plugin

getJmsSession

public XBSession getJmsSession()

Description copied from interface: I_ChangePublisher

Only used in replication, can return null if not used.

Specified by:

getJmsSession in interface I_ChangePublisher

Returns:

See Also:

I_ChangePublisher.getJmsSession()

compressOLD

public static byte[] compressOLD(byte[] buffer,
                                 java.util.Map props,
                                 int compressSizeLimit,
                                 java.lang.String zipType)

Deprecated.

Compresses the message if needed.

Parameters:

buffer - The buffer to compress

props - The properties to update with the compressed flag (uncompressed size)

compressSizeLimit - The limit for compression. If less than one no compression is done. If the size of the buffer is less than this limit it is not compressed either.

Returns:

the compressed buffer or the input buffer if no compression was needed.

compress

public static byte[] compress(byte[] buffer,
                              java.util.Map props,
                              int compressSizeLimit,
                              java.lang.String zipType)

Compresses the message if needed.

Parameters:

buffer - The buffer to compress

props - The properties to update with the compressed flag (uncompressed size)

compressSizeLimit - The limit for compression. If less than one no compression is done. If the size of the buffer is less than this limit it is not compressed either.

Returns:

the compressed buffer or the input buffer if no compression was needed.

dumpProps

private static final java.lang.String dumpProps(java.util.Map clientProperties)

decompressXX

public static byte[] decompressXX(byte[] buffer,
                                  java.util.Map clientProperties)

Deprecated. you should use the one with InputStream instead since less memory hungry (for big messages)

Parameters:

buffer -

clientProperties -

Returns:

decompress

public static java.io.InputStream decompress(java.io.InputStream is,
                                             java.util.Map clientProperties)