tigase.xmpp.impl

Class OfflineMessages

java.lang.Object

tigase.xmpp.XMPPProcessor

tigase.xmpp.impl.OfflineMessages

All Implemented Interfaces:

Comparable<XMPPImplIfc>, XMPPImplIfc, XMPPPostprocessorIfc, XMPPProcessorIfc

public class OfflineMessages
extends XMPPProcessor
implements XMPPPostprocessorIfc, XMPPProcessorIfc

OfflineMessages plugin implementation which follows XEP-0160: Best Practices for Handling Offline Messages specification. Responsible for storing messages send to offline users - either as a standalone plugin or as a processor for other plugins (e.g. AMP). Is registered to handle packets of type <presence>. Created: Mon Oct 16 13:28:53 2006

Author:

Artur Hefczyc

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	OfflineMessages.OfflineMsgRepositoryIfc
class	OfflineMessages.StampComparator Comparator interface implementation for the purpose of sorting Elements retrieved from the repository by the timestamp stored in delay element.

Field Summary

Fields

Modifier and Type	Field and Description
static String[]	MESSAGE_EVENT_PATH Field holds an array for element paths for which the plugin offers message saving capabilities.
static String[]	MESSAGE_HEADER_PATH Field holds an array for element paths for which the plugin offers processing capabilities.
protected static String	XMLNS Field holds default client namespace for stanzas.

Fields inherited from class tigase.xmpp.XMPPProcessor

ALL_NAMES, ALL_PATHS, cmpInfo

Fields inherited from interface tigase.xmpp.XMPPImplIfc

CLIENT_XMLNS

Constructor Summary

Constructors

Constructor and Description
OfflineMessages()

Method Summary

Methods

Modifier and Type	Method and Description
int	concurrentQueuesNo() Methods returns a preferable number of threads/packets queues for the plugin.
protected MsgRepositoryIfc	getMsgRepoImpl(NonAuthUserRepository repo, XMPPResourceConnection conn) Method allows obtaining instance of MsgRepositoryIfc interface implementation.
String	id() Method id returns a unique ID of the plugin.
void	init(Map<String,Object> settings) Method init is called just after the plugin has been loaded into memory.
protected boolean	loadOfflineMessages(Packet packet, XMPPResourceConnection conn) Method determines whether offline messages should be loaded - the process should be run only once per user session and only for available/null presence with priority greater than 0.
void	postProcess(Packet packet, XMPPResourceConnection conn, NonAuthUserRepository repo, Queue<Packet> queue, Map<String,Object> settings) Performs processing of packet for which there was no processor.
void	process(Packet packet, XMPPResourceConnection conn, NonAuthUserRepository repo, Queue<Packet> results, Map<String,Object> settings) OfflineMessages processor is triggered by <presence> stanza.
Queue<Packet>	restorePacketForOffLineUser(XMPPResourceConnection conn, MsgRepositoryIfc repo) Method restores all messages from repository for the JID of the current session.
boolean	savePacketForOffLineUser(Packet pac, MsgRepositoryIfc repo) Method stores messages to offline repository with the following rules applied, i.e.
tigase.xml.Element[]	supDiscoFeatures(XMPPResourceConnection session) Method supDiscoFeatures returns an array of XML Elements with service discovery features which have to be returned to the client uppon request.
String[][]	supElementNamePaths() Method supElementNamePaths returns an array of element names in form of a full path to the XML element for stanzas which can be processed by this plugin.
String[]	supNamespaces() Method supNamespaces returns an array of name-spaces for stanzas which can be processed by this plugin.

Methods inherited from class tigase.xmpp.XMPPProcessor

canHandle, compareTo, concurrentThreadsPerQueue, getComponentInfo, getInstance, getStatistics, isSupporting, supElements, supStreamFeatures, supTypes, toString

Methods inherited from class java.lang.Object

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

Methods inherited from interface tigase.xmpp.XMPPImplIfc

canHandle, concurrentThreadsPerQueue, getComponentInfo, getStatistics, isSupporting, supElements, supStreamFeatures, supTypes

Methods inherited from interface java.lang.Comparable

compareTo

Field Detail

XMLNS

protected static final String XMLNS

Field holds default client namespace for stanzas. In case of msgoffline plugin it is jabber:client

See Also:

Constant Field Values

MESSAGE_EVENT_PATH

public static final String[] MESSAGE_EVENT_PATH

Field holds an array for element paths for which the plugin offers message saving capabilities. In case of msgoffline plugin it is presence stanza

MESSAGE_HEADER_PATH

public static final String[] MESSAGE_HEADER_PATH

Field holds an array for element paths for which the plugin offers processing capabilities. In case of msgoffline plugin it is presence stanza

Constructor Detail

OfflineMessages

public OfflineMessages()

Method Detail

concurrentQueuesNo

public int concurrentQueuesNo()

Description copied from interface: XMPPImplIfc

Methods returns a preferable number of threads/packets queues for the plugin. This number can be overwritten through configuration settings, however, a default value should be reasonably good for most standard installations. It is recommended to assign at least as much as twice a number of CPUs cores for I/O bound processing and number a number equal to CPUs cores for fast processing not slowed down by any I/O.

Specified by:

concurrentQueuesNo in interface XMPPImplIfc

Overrides:

concurrentQueuesNo in class XMPPProcessor

Returns:

an integer preferred number of processing threads for the plugin.

id

public String id()

Description copied from interface: XMPPImplIfc

Method id returns a unique ID of the plugin. Each plugin has own, unique ID which is used in the configuration file to determine whether it needs to be loaded or not. In most cases the ID can be equal to XMLNS of the packages processed by the plugin.

Specified by:

id in interface XMPPImplIfc

Returns:

a String value

init

public void init(Map<String,Object> settings)
          throws TigaseDBException

Description copied from interface: XMPPImplIfc

Method init is called just after the plugin has been loaded into memory. The idea behind this is to allow it to initialize or check the database. This might be especially useful for plugins which want to have a database access via non-standard stored procedures or need schema upgrade.

Specified by:

init in interface XMPPImplIfc

Overrides:

init in class XMPPProcessor

Parameters:

settings - is a Map with initial processor settings from the configuration file.

Throws:

TigaseDBException

postProcess

public void postProcess(Packet packet,
               XMPPResourceConnection conn,
               NonAuthUserRepository repo,
               Queue<Packet> queue,
               Map<String,Object> settings)

Performs processing of packet for which there was no processor.

OfflineMessages postprocessor simply calls savePacketForOffLineUser method to store packet to offline repository.

Specified by:

postProcess in interface XMPPPostprocessorIfc

Parameters:

packet - packet is which being processed. This parameter may never be null. Even though this is not immutable object it mustn't be altered. None of it's fields or attributes can be changed during processing.

conn - user session which keeps all the user session data and also gives an access to the user's repository data. It allows for storing information in a permanent storage or in memory only during the live of the online session. This parameter can be null if there is no online user session at the time of the packet processing.

repo - this is a user data storage which is normally used when the user session (parameter above) is null. This is repository allows for a very restricted access only. It allows for storing some user private data (doesn't allow overwriting existing data) like messages for offline users and it also allows for reading user public data like VCard.

queue - this a collection with packets which have been generated as input packet processing results. Regardless a response to a user request is sent or the packet is forwarded to it's destination it is always required that a copy of the input packet is created and stored in the results queue.

settings - this map keeps plugin specific settings loaded from the Tigase server configuration. In most cases it is unused, however if the plugin needs to access an external database that this is a way to pass database connection string to the plugin.

process

public void process(Packet packet,
           XMPPResourceConnection conn,
           NonAuthUserRepository repo,
           Queue<Packet> results,
           Map<String,Object> settings)
             throws NotAuthorizedException

OfflineMessages processor is triggered by <presence> stanza. Upon receiving it plugin tries to load messages from repository and, if the result is not empty, sends them to the user

Specified by:

process in interface XMPPProcessorIfc

Parameters:

packet - packet is which being processed. This parameter may never be null. Even though this is not immutable object it mustn't be altered. None of it's fields or attributes can be changed during processing.

conn - user session which keeps all the user session data and also gives an access to the user's repository data. It allows for storing information in a permanent storage or in memory only during the live of the online session. This parameter can be null if there is no online user session at the time of the packet processing.

repo - this is a user data storage which is normally used when the user session (parameter above) is null. This is repository allows for a very restricted access only. It allows for storing some user private data (doesn't allow overwriting existing data) like messages for offline users and it also allows for reading user public data like VCard.

results - this a collection with packets which have been generated as input packet processing results. Regardless a response to a user request is sent or the packet is forwarded to it's destination it is always required that a copy of the input packet is created and stored in the results queue.

settings - this map keeps plugin specific settings loaded from the Tigase server configuration. In most cases it is unused, however if the plugin needs to access an external database that this is a way to pass database connection string to the plugin.

Throws:

NotAuthorizedException

restorePacketForOffLineUser

public Queue<Packet> restorePacketForOffLineUser(XMPPResourceConnection conn,
                                        MsgRepositoryIfc repo)
                                          throws UserNotFoundException,
                                                 NotAuthorizedException

Method restores all messages from repository for the JID of the current session. All retrieved elements are then instantiated as Packet objects added to LinkedList collection and, if possible, sorted by timestamp.

Parameters:

conn - user session which keeps all the user session data and also gives an access to the user's repository data.

repo - an implementation of MsgRepositoryIfc interface

Returns:

a Queue of Packet objects based on all stored payloads for the JID of the current session.

Throws:

UserNotFoundException

NotAuthorizedException

savePacketForOffLineUser

public boolean savePacketForOffLineUser(Packet pac,
                               MsgRepositoryIfc repo)
                                 throws UserNotFoundException

Method stores messages to offline repository with the following rules applied, i.e. saves only:

• message stanza with either nonempty <body>, <event> or <header> child element and only messages of type normal, chat.
• presence stanza of type subscribe, subscribed, unsubscribe and unsubscribed.

Processed messages are stamped with the delay element and appropriate timestamp.

Parameters:

pac - a Packet object containing packet that should be verified and saved

repo - a MsgRepositoryIfc repository handler responsible for storing messages

Returns:

true if the packet was correctly saved to repository, false otherwise.

Throws:

UserNotFoundException

supDiscoFeatures

public tigase.xml.Element[] supDiscoFeatures(XMPPResourceConnection session)

Description copied from interface: XMPPImplIfc

Method supDiscoFeatures returns an array of XML Elements with service discovery features which have to be returned to the client uppon request. Service discovery features returned by this method correspond to services supported by this plugin.

Specified by:

supDiscoFeatures in interface XMPPImplIfc

Overrides:

supDiscoFeatures in class XMPPProcessor

Parameters:

session - a XMPPResourceConnection value

Returns:

an Element[] value

supElementNamePaths

public String[][] supElementNamePaths()

Description copied from interface: XMPPImplIfc

Method supElementNamePaths returns an array of element names in form of a full path to the XML element for stanzas which can be processed by this plugin. Each element name path corresponds to XMLNS returned in array by supNamespaces() method. The element path itself is represented by a String array with each path element as a separate String.

Specified by:

supElementNamePaths in interface XMPPImplIfc

Overrides:

supElementNamePaths in class XMPPProcessor

Returns:

a String[][] value is an array for element paths for which the plugin offers processing capabilities. Each path is in form of a String array in order to reduce parsing overhead.

supNamespaces

public String[] supNamespaces()

Description copied from interface: XMPPImplIfc

Method supNamespaces returns an array of name-spaces for stanzas which can be processed by this plugin. Each namespace corresponds to element name returned in array by supElemenets() method.

Specified by:

supNamespaces in interface XMPPImplIfc

Overrides:

supNamespaces in class XMPPProcessor

Returns:

a String[] value

getMsgRepoImpl

protected MsgRepositoryIfc getMsgRepoImpl(NonAuthUserRepository repo,
                              XMPPResourceConnection conn)

Method allows obtaining instance of MsgRepositoryIfc interface implementation.

Parameters:

conn - user session which keeps all the user session data and also gives an access to the user's repository data.

repo - an implementation of MsgRepositoryIfc interface

Returns:

instance of MsgRepositoryIfc interface implementation.

loadOfflineMessages

protected boolean loadOfflineMessages(Packet packet,
                          XMPPResourceConnection conn)

Method determines whether offline messages should be loaded - the process should be run only once per user session and only for available/null presence with priority greater than 0.

Parameters:

packet - a Packet object containing packet that should be verified and saved

conn - user session which keeps all the user session data and also gives an access to the user's repository data.

Returns:

true if the messages should be loaded, false otherwise.