Class HistoryStrategy

  • All Implemented Interfaces:
    Externalizable, Serializable

    public class HistoryStrategy
    extends Object
    implements Externalizable

    Multi-User Chat rooms may cache history of the conversations in the room in order to play them back to newly arriving members.

    This class is an internal component of MUCRoomHistory that describes the strategy that can be used, and provides a method of administering the history behavior.

    Gaston Dombiak, Derek DeMoro, Guus der Kinderen,
    See Also:
    Serialized Form
    • Constructor Detail

      • HistoryStrategy

        public HistoryStrategy()
        This constructor is provided to comply with the Externalizable interface contract. It should not be used directly.
      • HistoryStrategy

        public HistoryStrategy​(org.xmpp.packet.JID roomJID,
                               HistoryStrategy parentStrategy)
        Create a history strategy with the given parent strategy (for defaults) or null if no parent exists.
        roomJID - the unique identifier of the room for which this strategy will store messages.
        parentStrategy - The parent strategy of this strategy or null if none exists.
    • Method Detail

      • getMaxNumber

        public int getMaxNumber()
        Obtain the maximum number of messages for strategies using message number limitations.
        The maximum number of messages to store in applicable strategies.
      • setMaxNumber

        public void setMaxNumber​(int max)
        Set the maximum number of messages for strategies using message number limitations.
        max - the maximum number of messages to store in applicable strategies.
      • setType

        public void setType​(HistoryStrategy.Type newType)
        Set the type of history strategy being used.
        newType - The new type of chat history to use.
      • getType

        public HistoryStrategy.Type getType()
        Obtain the type of history strategy being used.
        The current type of strategy being used.
      • addMessage

        public void addMessage​(@Nonnull
                               org.xmpp.packet.Message... packets)
        Add a message(s) to the current chat history. The strategy type will determine what actually happens to the message.
        packets - The messages to add to the chatroom's history.
      • getHistoryFromCache

        protected Queue<org.xmpp.packet.Message> getHistoryFromCache()
        Obtains the historic messages cached for this particular room from the cache. This method ensures that a room-based lock is acquired, before interacting with the cache. Note that modifications applied to the returned collection are not guaranteed to be applied to the cache. Explicitly put the collection back in the cache to ensure that changes are persisted there.
        The historic messages for this room.
      • getMessageHistory

        public Iterator<org.xmpp.packet.Message> getMessageHistory()
        Obtain the current history as an iterator of messages to play back to a new room member.
        An iterator of Message objects to be sent to the new room member.
      • getReverseMessageHistory

        public ListIterator<org.xmpp.packet.Message> getReverseMessageHistory()
        Obtain the current history to be iterated in reverse mode. This means that the returned list iterator will be positioned at the end of the history so senders of this message must traverse the list in reverse mode.
        A list iterator of Message objects positioned at the end of the list.
      • purge

        public void purge()
        Removes all history that is maintained for this instance.
      • setTypeFromString

        public void setTypeFromString​(String typeName)
        Obtain the strategy type from string name. See the Type enumeration name strings for the names strings supported. If nothing matches and parent is not null, then the default strategy is used. Otherwise the number strategy is used.
        typeName - the text name of the strategy type.
      • setContext

        public void setContext​(String subdomain,
                               String prefix)
        Sets the prefix to use for retrieving and saving settings (and also triggers an immediate loading of properties).
        subdomain - the subdomain of the muc service to pull properties for.
        prefix - the prefix to use (without trailing dot) on property names.
      • hasChangedSubject

        public boolean hasChangedSubject()
        Returns true if there is a message within the history of the room that has changed the room's subject.
        true if there is a message within the history of the room that has changed the room's subject.
      • getChangedSubject

        public org.xmpp.packet.Message getChangedSubject()
        Returns the message within the history of the room that has changed the room's subject.
        the latest room subject change or null if none exists yet.
      • isSubjectChangeRequest

        public boolean isSubjectChangeRequest​(org.xmpp.packet.Message message)
        Returns true if the given message qualifies as a subject change request for the target MUC room, per XEP-0045. Note that this does not validate whether the sender has permission to make the change, because subject change requests may be loaded from history or processed "live" during a user's session. Refer to for details.
        message - the message to check
        true if the given packet is a subject change request
      • hashCode

        public int hashCode()
        hashCode in class Object