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

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

All Implemented Interfaces:

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

public final class FreezableList<E>
extends TransformedList<E,E>

An EventList that shows the current contents of its source EventList.

When this EventList is frozen, changes to its source EventList will not be reflected. Instead, the FreezableList will continue to show the state of its source EventList at the time it was frozen.

When this EventList is thawed, changes to its source EventList will be reflected.

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

EventList Overview

Overview

Writable:	writable when thawed (default), not writable when frozen
Concurrency:	thread ready, not thread safe
Performance:	reads: O(1), writes O(1), freezes O(N)
Memory:	frozen: 4 bytes per element, thawed: 0 bytes per element
Unit Tests:	N/A
Issues:	N/A
Issues:

Author:

Jesse Wilson

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

FreezableList(EventList<E> source)
Creates a FreezableList that can freeze the view of the specified source EventList.

Method Summary

void	freeze() Locks this FreezableList on the current state of the source EventList.
E	get(int index) Returns the element at the specified position in this list.
boolean	isFrozen() Gets whether this EventList is showing a previous state of the source EventList.
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.
int	size() Returns the number of elements in this list.
void	thaw() Unlocks this FreezableList to show the same contents of the source EventList.

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

add, addAll, clear, dispose, getSourceIndex, remove, removeAll, retainAll, set

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

FreezableList

public FreezableList(EventList<E> source)

Creates a FreezableList that can freeze the view of the specified source EventList.

Method Detail

get

public E get(int index)

Returns the element at the specified position in this list.

Specified by:

get in interface List<E>

Overrides:

get in class TransformedList<E,E>

Parameters:

index - index of element to return.

Returns:

the element at the specified position in this list.

size

public int size()

Returns the number of elements in this list. If this list contains more than Integer.MAX_VALUE elements, returns Integer.MAX_VALUE.

Specified by:

size in interface Collection<E>

Specified by:

size in interface List<E>

Overrides:

size in class TransformedList<E,E>

Returns:

the number of elements in this list.

isWritable

protected boolean isWritable()

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>

isFrozen

public boolean isFrozen()

Gets whether this EventList is showing a previous state of the source EventList.

Returns:

true if this list is showing a previous state of the source EventList or false if this is showing the current state of the source EventList.

freeze

public void freeze()

Locks this FreezableList on the current state of the source EventList. While frozen, changes to the source EventList will not be reflected by this list.

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

thaw

public void thaw()

Unlocks this FreezableList to show the same contents of the source EventList. When thawed, changes to the source EventList will be reflected by this list.

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

listChanged

public void listChanged(ListEvent<E> listChanges)

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>