de.lmu.ifi.dbs.elki.database

Class DatabaseEventManager

java.lang.Object

de.lmu.ifi.dbs.elki.database.DatabaseEventManager

public class DatabaseEventManager
extends Object

Class to manage database events such as insertions and removals.

Author:

Elke Achtert

Nested Class Summary

Nested Classes

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

Field Summary

Fields

Modifier and Type	Field and 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 List<DataStoreListener>	dataListenerList Holds the listeners for data store changes
private HashSetModifiableDBIDs	dataStoreObjects The objects that were changed in the current DataStoreEvent.
private List<ResultListener>	resultListenerList Holds the listeners for result changes.

Constructor Summary

Constructors

Constructor and Description
DatabaseEventManager()

Method Summary

Modifier and Type	Method and Description
void	accumulateDataStoreEvents() Collects successive insertion, deletion or update events.
void	addListener(DataStoreListener l) Adds a DataStoreListener for a DataStoreEvent posted after the content of the database changes.
void	addListener(ResultListener l) Adds a ResultListener to be notified on new results.
private void	fireObjectChanged(DBIDRef object, DatabaseEventManager.Type type) Handles a DataStoreEvent with the specified type.
void	fireObjectInserted(DBIDRef insertion) Event when a new object was inserted.
protected void	fireObjectRemoved(DBIDRef deletion) Event when an objects was removed / deleted.
private void	fireObjectsChanged(DBIDs objects, DatabaseEventManager.Type type) Handles a DataStoreEvent with the specified type.
void	fireObjectsInserted(DBIDs insertions) Event when new objects are inserted.
protected void	fireObjectsRemoved(DBIDs deletions) Event when objects were removed / deleted.
void	fireObjectsUpdated(DBIDRef update) Event when an object was changed / updated.
void	fireObjectsUpdated(DBIDs updates) Event when objects have changed / were updated.
void	fireResultAdded(Result r, Result parent) Informs all registered ResultListener that a new result was added.
void	fireResultRemoved(Result r, Result 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(DataStoreListener l) Removes a DataStoreListener previously added with addListener(DataStoreListener).
void	removeListener(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 List<DataStoreListener> dataListenerList

Holds the listeners for data store changes

resultListenerList

private List<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 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(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

removeListener

public void removeListener(DataStoreListener l)

Removes a DataStoreListener previously added with addListener(DataStoreListener).

Parameters:

l - the listener to remove

See Also:

addListener(DataStoreListener), DataStoreListener, DataStoreEvent

addListener

public void addListener(ResultListener l)

Adds a ResultListener to be notified on new results.

Parameters:

l - the listener to add

See Also:

removeListener(ResultListener), ResultListener, Result

removeListener

public void removeListener(ResultListener l)

Removes a ResultListener previously added with addListener(ResultListener).

Parameters:

l - the listener to remove

See Also:

addListener(ResultListener), ResultListener, Result

fireObjectsInserted

public void fireObjectsInserted(DBIDs insertions)

Event when new objects are inserted.

Parameters:

insertions - the objects that have been inserted

fireObjectInserted

public void fireObjectInserted(DBIDRef insertion)

Event when a new object was inserted.

Parameters:

insertion - the object that was inserted

fireObjectsUpdated

public void fireObjectsUpdated(DBIDs updates)

Event when objects have changed / were updated.

Parameters:

updates - the objects that have been updated

fireObjectsUpdated

public void fireObjectsUpdated(DBIDRef update)

Event when an object was changed / updated.

Parameters:

update - the object that was updated

fireObjectsRemoved

protected void fireObjectsRemoved(DBIDs deletions)

Event when objects were removed / deleted.

Parameters:

deletions - the objects that have been removed

fireObjectRemoved

protected void fireObjectRemoved(DBIDRef deletion)

Event when an objects was removed / deleted.

Parameters:

deletion - the object that has was removed

fireObjectsChanged

private void fireObjectsChanged(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(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(Result r,
                            Result 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(Result r,
                              Result 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