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 `Element`s 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 `Element`s 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.

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