Package elki.database

Class DatabaseEventManager

  • public class DatabaseEventManager
extends java.lang.Object
    Class to manage database events such as insertions and removals.
    Since:
    0.4.0
    Author:
    Elke Achtert

    • Nested Class Summary

      Nested Classes 
      Modifier and Type Class Description
      private static class  DatabaseEventManager.Type
      Types for aggregation.

    • Field Summary

      Fields 
      Modifier and Type Field Description
      private boolean accumulateDataStoreEvents
      Indicates whether DataStoreEvents should be accumulated and fired as one event on demand.
      private DatabaseEventManager.Type currentDataStoreEventType
      The type of the current DataStoreEvent to be accumulated.
      private java.util.List<elki.database.datastore.DataStoreListener> dataListenerList
      Holds the listeners for data store changes
      private elki.database.ids.HashSetModifiableDBIDs dataStoreObjects
      The objects that were changed in the current DataStoreEvent.
      private java.util.List<elki.result.ResultListener> resultListenerList
      Holds the listeners for result changes.

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      void accumulateDataStoreEvents()
      Collects successive insertion, deletion or update events.
      void addListener​(elki.database.datastore.DataStoreListener l)
      Adds a DataStoreListener for a DataStoreEvent posted after the content of the database changes.
      void addListener​(elki.result.ResultListener l)
      Adds a ResultListener to be notified on new results.
      private void fireObjectChanged​(elki.database.ids.DBIDRef object, DatabaseEventManager.Type type)
      Handles a DataStoreEvent with the specified type.
      void fireObjectInserted​(elki.database.ids.DBIDRef insertion)
      Event when a new object was inserted.
      protected void fireObjectRemoved​(elki.database.ids.DBIDRef deletion)
      Event when an objects was removed / deleted.
      private void fireObjectsChanged​(elki.database.ids.DBIDs objects, DatabaseEventManager.Type type)
      Handles a DataStoreEvent with the specified type.
      void fireObjectsInserted​(elki.database.ids.DBIDs insertions)
      Event when new objects are inserted.
      protected void fireObjectsRemoved​(elki.database.ids.DBIDs deletions)
      Event when objects were removed / deleted.
      void fireObjectsUpdated​(elki.database.ids.DBIDRef update)
      Event when an object was changed / updated.
      void fireObjectsUpdated​(elki.database.ids.DBIDs updates)
      Event when objects have changed / were updated.
      void fireResultAdded​(java.lang.Object r, java.lang.Object parent)
      Informs all registered ResultListener that a new result was added.
      void fireResultRemoved​(java.lang.Object r, java.lang.Object parent)
      Informs all registered ResultListener that a new result has been removed.
      void flushDataStoreEvents()
      Fires all collected insertion, deletion or update events as one DataStoreEvent, i.e. notifies all registered DataStoreListener how the content of the database has been changed since accumulateDataStoreEvents() was called.
      void removeListener​(elki.database.datastore.DataStoreListener l)
      Removes a DataStoreListener previously added with addListener(DataStoreListener).
      void removeListener​(elki.result.ResultListener l)
      Removes a ResultListener previously added with addListener(ResultListener).

      • Methods inherited from class java.lang.Object

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

    • Field Detail

      • dataListenerList

        private java.util.List<elki.database.datastore.DataStoreListener> dataListenerList
        Holds the listeners for data store changes

      • resultListenerList

        private java.util.List<elki.result.ResultListener> resultListenerList
        Holds the listeners for result changes.

      • accumulateDataStoreEvents

        private boolean accumulateDataStoreEvents
        Indicates whether DataStoreEvents should be accumulated and fired as one event on demand.

      • currentDataStoreEventType

        private DatabaseEventManager.Type currentDataStoreEventType
        The type of the current DataStoreEvent to be accumulated.

      • dataStoreObjects

        private elki.database.ids.HashSetModifiableDBIDs dataStoreObjects
        The objects that were changed in the current DataStoreEvent.

    • Constructor Detail

      • DatabaseEventManager

        public DatabaseEventManager()

    • Method Detail

      • accumulateDataStoreEvents

        public void accumulateDataStoreEvents()
        Collects successive insertion, deletion or update events. The accumulated event will be fired when flushDataStoreEvents() is called or a different event type occurs.
        See Also:
        flushDataStoreEvents(), DataStoreEvent

      • flushDataStoreEvents

        public void flushDataStoreEvents()
        Fires all collected insertion, deletion or update events as one DataStoreEvent, i.e. notifies all registered DataStoreListener how the content of the database has been changed since accumulateDataStoreEvents() was called.
        See Also:
        accumulateDataStoreEvents, DataStoreListener, DataStoreEvent

      • addListener

        public void addListener​(elki.database.datastore.DataStoreListener l)
        Adds a DataStoreListener for a DataStoreEvent posted after the content of the database changes.
        Parameters:
        l - the listener to add
        See Also:
        removeListener(DataStoreListener), DataStoreListener, DataStoreEvent

      • addListener

        public void addListener​(elki.result.ResultListener l)
        Adds a ResultListener to be notified on new results.
        Parameters:
        l - the listener to add
        See Also:
        removeListener(ResultListener), ResultListener

      • fireObjectsInserted

        public void fireObjectsInserted​(elki.database.ids.DBIDs insertions)
        Event when new objects are inserted.
        Parameters:
        insertions - the objects that have been inserted

      • fireObjectInserted

        public void fireObjectInserted​(elki.database.ids.DBIDRef insertion)
        Event when a new object was inserted.
        Parameters:
        insertion - the object that was inserted

      • fireObjectsUpdated

        public void fireObjectsUpdated​(elki.database.ids.DBIDs updates)
        Event when objects have changed / were updated.
        Parameters:
        updates - the objects that have been updated

      • fireObjectsUpdated

        public void fireObjectsUpdated​(elki.database.ids.DBIDRef update)
        Event when an object was changed / updated.
        Parameters:
        update - the object that was updated

      • fireObjectsRemoved

        protected void fireObjectsRemoved​(elki.database.ids.DBIDs deletions)
        Event when objects were removed / deleted.
        Parameters:
        deletions - the objects that have been removed

      • fireObjectRemoved

        protected void fireObjectRemoved​(elki.database.ids.DBIDRef deletion)
        Event when an objects was removed / deleted.
        Parameters:
        deletion - the object that has was removed

      • fireObjectsChanged

        private void fireObjectsChanged​(elki.database.ids.DBIDs objects,
                                DatabaseEventManager.Type type)
        Handles a DataStoreEvent with the specified type. If the current event type is not equal to the specified type, the events accumulated up to now will be fired first. The new event will be aggregated and fired on demand if accumulateDataStoreEvents is set, otherwise all registered DataStoreListener will be notified immediately that the content of the database has been changed.
        Parameters:
        objects - the objects that have been changed, i.e. inserted, deleted or updated

      • fireObjectChanged

        private void fireObjectChanged​(elki.database.ids.DBIDRef object,
                               DatabaseEventManager.Type type)
        Handles a DataStoreEvent with the specified type. If the current event type is not equal to the specified type, the events accumulated up to now will be fired first. The new event will be aggregated and fired on demand if accumulateDataStoreEvents is set, otherwise all registered DataStoreListener will be notified immediately that the content of the database has been changed.
        Parameters:
        object - the object that has been changed, i.e. inserted, deleted or updated

      • fireResultAdded

        public void fireResultAdded​(java.lang.Object r,
                            java.lang.Object parent)
        Informs all registered ResultListener that a new result was added.
        Parameters:
        r - New child result added
        parent - Parent result that was added to

      • fireResultRemoved

        public void fireResultRemoved​(java.lang.Object r,
                              java.lang.Object parent)
        Informs all registered ResultListener that a new result has been removed.
        Parameters:
        r - result that has been removed
        parent - Parent result that has been removed