com.levigo.util.base.glazedlists.event
Class ListEventAssembler<E>

java.lang.Object
  com.levigo.util.base.glazedlists.event.ListEventAssembler<E>

public final class ListEventAssembler<E>
extends Object

Models a continuous stream of changes on a list. Changes of the same type that occur on a continuous set of rows are grouped into blocks automatically for performance benefits.

Atomic sets of changes may involve many lines of changes and many blocks of changes. They are committed to the queue in one action. No other threads should be creating a change on the same list change queue when an atomic change is being created.

Author:

Jesse Wilson

Field Summary

protected boolean	allowNestedEvents whether to allow nested events
protected int	eventLevel the event level is the number of nested events
protected int[]	reorderMap the current reordering array if this change is a reorder
protected EventList<E>	sourceList the list that this tracks changes for

Constructor Summary

ListEventAssembler(EventList<E> sourceList, ListEventPublisher publisher)
Creates a new ListEventAssembler that tracks changes for the specified list.

Method Summary

void	addChange(int type, int index) Deprecated. replaced with elementInserted(int, E), elementUpdated(int, E, E) and elementDeleted(int, E).
void	addChange(int type, int startIndex, int endIndex) Deprecated. replaced with elementInserted(int, E), elementUpdated(int, E, E) and elementDeleted(int, E).
void	addDelete(int index) Deprecated. replaced with elementDeleted(int, E).
void	addDelete(int startIndex, int endIndex) Deprecated. replaced with elementDeleted(int, E).
void	addInsert(int index) Deprecated. replaced with elementInserted(int, E).
void	addInsert(int startIndex, int endIndex) Deprecated. replaced with elementInserted(int, E).
void	addListEventListener(ListEventListener<? super E> listChangeListener) Registers the specified listener to be notified whenever new changes are appended to this list change sequence.
void	addUpdate(int index) Deprecated. replaced with elementUpdated(int, E, E).
void	addUpdate(int startIndex, int endIndex) Deprecated. replaced with elementUpdated(int, E, E).
void	beginEvent() Starts a new atomic change to this list change queue.
void	beginEvent(boolean allowNestedEvents) Starts a new atomic change to this list change queue.
void	commitEvent() Commits the current atomic change to this list change queue.
static ListEventPublisher	createListEventPublisher() Create a new ListEventPublisher for an EventList not attached to any other EventLists.
void	discardEvent() Discards the current atomic change to this list change queue.
void	elementDeleted(int index, E oldValue) Add to the current ListEvent the removal of the element at the specified index, with the specified previous value.
void	elementInserted(int index, E newValue) Add to the current ListEvent the insert of the element at the specified index, with the specified previous value.
void	elementsInserted(int index, int length)
void	elementUpdated(int index, E oldValue) Deprecated. replaced with elementUpdated(int, Object, Object).
void	elementUpdated(int index, E oldValue, E newValue) Add to the current ListEvent the update of the element at the specified index, with the specified previous value.
void	forwardEvent(ListEvent<?> listChanges) Forwards the event.
List<ListEventListener<E>>	getListEventListeners() Get all ListEventListeners observing the EventList.
boolean	isEventEmpty() Returns true if the current atomic change to this list change queue is empty; false otherwise.
void	removeListEventListener(ListEventListener<? super E> listChangeListener) Removes the specified listener from receiving notification when new changes are appended to this list change sequence.
void	reorder(int[] reorderMap) Sets the current event as a reordering.

Methods inherited from class java.lang.Object

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

Field Detail

sourceList

protected EventList<E> sourceList

the list that this tracks changes for

eventLevel

protected int eventLevel

the event level is the number of nested events

allowNestedEvents

protected boolean allowNestedEvents

whether to allow nested events

reorderMap

protected int[] reorderMap

the current reordering array if this change is a reorder

Constructor Detail

ListEventAssembler

public ListEventAssembler(EventList<E> sourceList,
                          ListEventPublisher publisher)

Creates a new ListEventAssembler that tracks changes for the specified list.

Method Detail

createListEventPublisher

public static ListEventPublisher createListEventPublisher()

Create a new ListEventPublisher for an EventList not attached to any other EventLists.

beginEvent

public void beginEvent()

Starts a new atomic change to this list change queue.

This simple change event does not support change events nested within. To allow other methods to nest change events within a change event, use beginEvent(true).

beginEvent

public void beginEvent(boolean allowNestedEvents)

Starts a new atomic change to this list change queue. This signature allows you to specify allowing nested changes. This simply means that you can call other methods that contain a beginEvent(), commitEvent() block and their changes will be recorded but not fired. This allows the creation of list modification methods to call simpler list modification methods while still firing a single ListEvent to listeners.

Parameters:

allowNestedEvents - false to throw an exception if another call to beginEvent() is made before the next call to commitEvent(). Nested events allow multiple method's events to be composed into a single event.

See Also:

Bug 52

elementInserted

public void elementInserted(int index,
                            E newValue)

Add to the current ListEvent the insert of the element at the specified index, with the specified previous value.

elementUpdated

public void elementUpdated(int index,
                           E oldValue,
                           E newValue)

Add to the current ListEvent the update of the element at the specified index, with the specified previous value.

elementDeleted

public void elementDeleted(int index,
                           E oldValue)

Add to the current ListEvent the removal of the element at the specified index, with the specified previous value.

elementUpdated

@Deprecated
public void elementUpdated(int index,
                                      E oldValue)

Deprecated. replaced with elementUpdated(int, Object, Object).

addChange

@Deprecated
public void addChange(int type,
                                 int startIndex,
                                 int endIndex)

Deprecated. replaced with elementInserted(int, E), elementUpdated(int, E, E) and elementDeleted(int, E).

Adds a block of changes to the set of list changes. The change block allows a range of changes to be grouped together for efficiency.

One or more calls to this method must be prefixed by a call to beginEvent() and followed by a call to commitEvent().

addChange

@Deprecated
public void addChange(int type,
                                 int index)

Deprecated. replaced with elementInserted(int, E), elementUpdated(int, E, E) and elementDeleted(int, E).

Convenience method for appending a single change of the specified type.

addInsert

@Deprecated
public void addInsert(int index)

Deprecated. replaced with elementInserted(int, E).

Convenience method for appending a single insert.

addDelete

@Deprecated
public void addDelete(int index)

Deprecated. replaced with elementDeleted(int, E).

Convenience method for appending a single delete.

addUpdate

@Deprecated
public void addUpdate(int index)

Deprecated. replaced with elementUpdated(int, E, E).

Convenience method for appending a single update.

addInsert

@Deprecated
public void addInsert(int startIndex,
                                 int endIndex)

Deprecated. replaced with elementInserted(int, E).

Convenience method for appending a range of inserts.

addDelete

@Deprecated
public void addDelete(int startIndex,
                                 int endIndex)

Deprecated. replaced with elementDeleted(int, E).

Convenience method for appending a range of deletes.

addUpdate

@Deprecated
public void addUpdate(int startIndex,
                                 int endIndex)

Deprecated. replaced with elementUpdated(int, E, E).

Convenience method for appending a range of updates.

reorder

public void reorder(int[] reorderMap)

Sets the current event as a reordering. Reordering events cannot be combined with other events.

forwardEvent

public void forwardEvent(ListEvent<?> listChanges)

Forwards the event. This is a convenience method that does the following:
1. beginEvent()
2. For all changes in sourceEvent, apply those changes to this
3. commitEvent()

Note that this method should be preferred to manually forwarding events because it is heavily optimized.

Note that currently this implementation does a best effort to preserve reorderings. This means that a reordering is lost if it is combined with any other ListEvent.

commitEvent

public void commitEvent()

Commits the current atomic change to this list change queue. This will notify all listeners about the change.

If the current event is nested within a greater event, this will simply change the nesting level so that further changes are applied directly to the parent change.

discardEvent

public void discardEvent()

Discards the current atomic change to this list change queue. This does not notify any listeners about any changes.

The caller of this method is responsible for returning the EventList to its state before the event began. If they fail to do so, the EventList pipeline may be in an inconsistent state.

If the current event is nested within a greater event, this will discard changes at the current nesting level and that further changes are still applied directly to the parent change.

isEventEmpty

public boolean isEventEmpty()

Returns true if the current atomic change to this list change queue is empty; false otherwise.

Returns:

true if the current atomic change to this list change queue is empty; false otherwise

addListEventListener

public void addListEventListener(ListEventListener<? super E> listChangeListener)

Registers the specified listener to be notified whenever new changes are appended to this list change sequence.

For each listener, a ListEvent is created, which provides a read-only view to the list changes in the list. The same ListChangeView object is used for all notifications to the specified listener, so if a listener does not process a set of changes, those changes will persist in the next notification.

removeListEventListener

public void removeListEventListener(ListEventListener<? super E> listChangeListener)

Removes the specified listener from receiving notification when new changes are appended to this list change sequence.

This uses the == identity comparison to find the listener instead of equals(). This is because multiple Lists may be listening and therefore equals() may be ambiguous.

getListEventListeners

public List<ListEventListener<E>> getListEventListeners()

Get all ListEventListeners observing the EventList.

elementsInserted

public void elementsInserted(int index,
                             int length)