com.levigo.util.base.glazedlists
Class ObservableElementList<E>

java.lang.Object
  com.levigo.util.base.glazedlists.AbstractEventList<E>
      com.levigo.util.base.glazedlists.TransformedList<E,E>
          com.levigo.util.base.glazedlists.ObservableElementList<E>

All Implemented Interfaces:

ListEventListener<E>, EventList<E>, Iterable<E>, Collection<E>, EventListener, List<E>

public class ObservableElementList<E>
extends TransformedList<E,E>

A list that fires update events whenever elements are modified in place. Changes to list elements are detected by registering an appropriate listener on every list element. Listeners are registered as elements are added to this list and unregistered as elements are removed from this list. Users must specify an implementation of a ObservableElementList.Connector in the constructor which contains the necessary logic for registering and unregistering a listener capable of detecting modifications to an observable list element.

Warning: This class is thread ready but not thread safe. See EventList for an example of thread safe code.

EventList Overview

Overview

Writable:	yes
Concurrency:	thread ready, not thread safe; elementChanged(), however, is thread ready
Performance:	inserts: O(1), deletes: O(1), updates: O(1), elementChanged: O(n)
Memory:	8 bytes per element
Unit Tests:	ObservableElementListTest
Issues:	N/A

Author:

Jesse Wilson, James Lemieux

See Also:

GlazedLists.beanConnector(Class), GlazedLists.beanConnector(Class, String, String), RFE 157

Nested Class Summary

static interface

ObservableElementList.Connector<E> An interface defining the methods required for registering and unregistering change listeners on list elements within an ObservableElementList.

Field Summary

Fields inherited from class com.levigo.util.base.glazedlists.TransformedList

source

Fields inherited from class com.levigo.util.base.glazedlists.AbstractEventList

publisher, readWriteLock, updates

Constructor Summary

ObservableElementList(EventList<E> source, ObservableElementList.Connector<? super E> elementConnector)
Constructs an ObservableElementList which wraps the given source and uses the given elementConnector to register/unregister change listeners on elements of the source.

Method Summary

void	dispose() Releases the resources consumed by this TransformedList so that it may eventually be garbage collected.
void	elementChanged(E listElement) Handle a listener being notified for the specified listElement.
protected boolean	isWritable() Gets whether the source EventList is writable via this API.
void	listChanged(ListEvent<E> listChanges) When the underlying list changes, this notification allows the object to repaint itself or update itself as necessary.

Methods inherited from class com.levigo.util.base.glazedlists.TransformedList

add, addAll, clear, get, getSourceIndex, remove, removeAll, retainAll, set, size

Methods inherited from class com.levigo.util.base.glazedlists.AbstractEventList

add, addAll, addListEventListener, contains, containsAll, equals, getPublisher, getReadWriteLock, hashCode, indexOf, isEmpty, iterator, lastIndexOf, listIterator, listIterator, remove, removeListEventListener, subList, toArray, toArray, toString

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

ObservableElementList

public ObservableElementList(EventList<E> source,
                             ObservableElementList.Connector<? super E> elementConnector)

Constructs an ObservableElementList which wraps the given source and uses the given elementConnector to register/unregister change listeners on elements of the source.

Parameters:

source - the EventList to transform

elementConnector - the ObservableElementList.Connector to consult when list elements are added or removed and thus element listeners must be registered or unregistered. Note that this constructor attachs this list to the given elementConnector by calling ObservableElementList.Connector.setObservableElementList(ObservableElementList).

Method Detail

listChanged

public void listChanged(ListEvent<E> listChanges)

Description copied from class: TransformedList

When the underlying list changes, this notification allows the object to repaint itself or update itself as necessary.

It is mandatory that the calling thread has obtained the write lock on the source list. This is because the calling thread will have written to the source list to cause this event. This condition guarantees that no writes can occur while the listener is handling this event. It is an error to write to the source list while processing an event.

Specified by:

listChanged in interface ListEventListener<E>

Specified by:

listChanged in class TransformedList<E,E>

isWritable

protected boolean isWritable()

Description copied from class: TransformedList

Gets whether the source EventList is writable via this API.

Extending classes must override this method in order to make themselves writable.

Specified by:

isWritable in class TransformedList<E,E>

dispose

public void dispose()

Releases the resources consumed by this TransformedList so that it may eventually be garbage collected. In this case of this TransformedList, it uses the ObservableElementList.Connector to remove all listeners from their associated list elements and finally removes the reference to this list from the Connector by calling ObservableElementList.Connector.setObservableElementList(ObservableElementList) with a null argument.

Warning: It is an error to call any method on a TransformedList after it has been disposed.

Specified by:

dispose in interface EventList<E>

Overrides:

dispose in class TransformedList<E,E>

elementChanged

public void elementChanged(E listElement)

Handle a listener being notified for the specified listElement. This method causes a ListEvent to be fired from this EventList indicating an update occurred at all locations of the given listElement.

Note that listElement must be the exact object located within this list (i.e. listElement == get(i) for some i >= 0).

This method acquires the write lock for this list before locating the listElement and broadcasting its update. It is assumed that this method may be called on any Thread, so to decrease the burdens of the caller in achieving multi-threaded correctness, this method is Thread ready.

Parameters:

listElement - the list element which has been modified