Module javafx.base

Package javafx.collections

Class ObservableListBase<E>

java.lang.Object

java.util.AbstractCollection<E>

java.util.AbstractList<E>

javafx.collections.ObservableListBase<E>

Type Parameters:

E - the type of the elements contained in the List

All Implemented Interfaces:

Iterable<E>, Collection<E>, List<E>, Observable, ObservableList<E>

Direct Known Subclasses:

ModifiableObservableListBase, TransformationList

public abstract class ObservableListBase<E>
extends AbstractList<E>
implements ObservableList<E>

Abstract class that serves as a base class for ObservableList implementations. The base class provides two functionalities for the implementing classes.

• Listener handling by implementing addListener and removeListener methods. fireChange(javafx.collections.ListChangeListener.Change) method is provided for notifying the listeners with a Change object.
• Methods for building up a ListChangeListener.Change object. There are various methods called next*, like nextAdd(int, int) for new items in the lists or nextRemove(int, java.lang.Object) for an item being removed from the list.

  These methods must be always enclosed in beginChange() and endChange() block.

  See the example below.

The following example shows how the Change build-up works:

  public void removeOddIndexes() {
      beginChange();
      try {
          for (int i = 1; i < size(); ++i) {
              remove(i);
          }
      } finally {
          endChange();
      }
  }

  public void remove(int i) {
      beginChange();
      try {
          E removed = ... //do some stuff that will actually remove the element at index i
          nextRemove(i, removed);
      } finally {
          endChange();
      }
  }

 

The try/finally blocks in the example are needed only if there's a possibility for an exception to occur inside a beginChange() / endChange() block

Note: If you want to create modifiable ObservableList implementation, consider using ModifiableObservableListBase as a superclass.

Note: In order to create list with sequential access, you should override AbstractList.listIterator(), AbstractList.iterator() methods and use them in AbstractList.get(int), AbstractCollection.size() and other methods accordingly.

Since:

JavaFX 8.0

See Also:

ObservableList, ListChangeListener.Change, ModifiableObservableListBase

Field Summary

Fields inherited from class java.util.AbstractList

modCount

Constructor Summary

Constructors

Constructor	Description
ObservableListBase()

Method Summary

Modifier and Type	Method	Description
boolean	addAll(E... elements)	A convenience method for var-arg addition of elements.
void	addListener(InvalidationListener listener)	Adds an InvalidationListener which will be notified whenever the Observable becomes invalid.
void	addListener(ListChangeListener<? super E> listener)	Add a listener to this observable list.
protected void	beginChange()	Begins a change block.
protected void	endChange()	Ends the change block.
protected void	fireChange(ListChangeListener.Change<? extends E> change)	Notifies all listeners of a change
protected boolean	hasListeners()	Returns true if there are some listeners registered for this list.
protected void	nextAdd(int from, int to)	Adds a new add operation to the change.
protected void	nextPermutation(int from, int to, int[] perm)	Adds a new permutation operation to the change.
protected void	nextRemove(int idx, E removed)	Adds a new remove operation to the change with single item removed.
protected void	nextRemove(int idx, List<? extends E> removed)	Adds a new remove operation to the change with multiple items removed.
protected void	nextReplace(int from, int to, List<? extends E> removed)	Adds a new replace operation to the change.
protected void	nextSet(int idx, E old)	Adds a new set operation to the change.
protected void	nextUpdate(int pos)	Adds a new update operation to the change.
void	remove(int from, int to)	A simplified way of calling sublist(from, to).clear().
boolean	removeAll(E... elements)	A convenience method for var-arg usage of the removeAll method.
void	removeListener(InvalidationListener listener)	Removes the given listener from the list of listeners, that are notified whenever the value of the Observable becomes invalid.
void	removeListener(ListChangeListener<? super E> listener)	Tries to remove a listener from this observable list.
boolean	retainAll(E... elements)	A convenience method for var-arg usage of the retainAll method.
boolean	setAll(E... elements)	Clears the ObservableList and adds all the elements passed as var-args.
boolean	setAll(Collection<? extends E> col)	Clears the ObservableList and adds all elements from the collection.

Methods inherited from class java.util.AbstractCollection

addAll, contains, containsAll, isEmpty, remove, removeAll, retainAll, size, toArray, toArray, toString

Methods inherited from class java.util.AbstractList

add, add, addAll, clear, equals, get, hashCode, indexOf, iterator, lastIndexOf, listIterator, listIterator, remove, removeRange, set, subList

Methods inherited from interface java.util.Collection

parallelStream, removeIf, stream

Methods inherited from interface java.lang.Iterable

forEach

Methods inherited from interface java.util.List

add, add, addAll, addAll, clear, contains, containsAll, equals, get, hashCode, indexOf, isEmpty, iterator, lastIndexOf, listIterator, listIterator, of, of, of, of, of, of, of, of, of, of, of, of, remove, remove, removeAll, replaceAll, retainAll, set, size, sort, spliterator, subList, toArray, toArray

Methods inherited from class java.lang.Object

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

Methods inherited from interface javafx.collections.ObservableList

filtered, sorted, sorted

Constructor Detail

ObservableListBase

public ObservableListBase()

Method Detail

nextUpdate

protected final void nextUpdate(int pos)

Adds a new update operation to the change.

Note: needs to be called inside beginChange() / endChange() block.

Note: needs to reflect the current state of the list.

Parameters:

pos - the position in the list where the updated element resides.

nextSet

protected final void nextSet(int idx,
                             E old)

Adds a new set operation to the change. Equivalent to nextRemove(idx); nextAdd(idx, idx + 1); .

Note: needs to be called inside beginChange() / endChange() block.

Note: needs to reflect the current state of the list.

Parameters:

idx - the index of the item that was set

old - the old value at the idx position.

nextReplace

protected final void nextReplace(int from,
                                 int to,
                                 List<? extends E> removed)

Adds a new replace operation to the change. Equivalent to nextRemove(from, removed); nextAdd(from, to);

Note: needs to be called inside beginChange() / endChange() block.

Note: needs to reflect the current state of the list.

Parameters:

from - the index where the items were replaced

to - the end index (exclusive) of the range where the new items reside

removed - the list of items that were removed

nextRemove

protected final void nextRemove(int idx,
                                List<? extends E> removed)

Adds a new remove operation to the change with multiple items removed.

Note: needs to be called inside beginChange() / endChange() block.

Note: needs to reflect the current state of the list.

Parameters:

idx - the index where the items were removed

removed - the list of items that were removed

nextRemove

protected final void nextRemove(int idx,
                                E removed)

Adds a new remove operation to the change with single item removed.

Note: needs to be called inside beginChange() / endChange() block.

Note: needs to reflect the current state of the list.

Parameters:

idx - the index where the item was removed

removed - the item that was removed

nextPermutation

protected final void nextPermutation(int from,
                                     int to,
                                     int[] perm)

Adds a new permutation operation to the change. The permutation on index "i" contains the index, where the item from the index "i" was moved.

It's not necessary to provide the smallest permutation possible. It's correct to always call this method with nextPermutation(0, size(), permutation);

Note: needs to be called inside beginChange() / endChange() block.

Note: needs to reflect the current state of the list.

Parameters:

from - marks the beginning (inclusive) of the range that was permutated

to - marks the end (exclusive) of the range that was permutated

perm - the permutation in that range. Even if from != 0, the array should contain the indexes of the list. Therefore, such permutation would not contain indexes of range (0, from)

nextAdd

protected final void nextAdd(int from,
                             int to)

Adds a new add operation to the change. There's no need to provide the list of added items as they can be found directly in the list under the specified indexes.

Note: needs to be called inside beginChange() / endChange() block.

Note: needs to reflect the current state of the list.

Parameters:

from - marks the beginning (inclusive) of the range that was added

to - marks the end (exclusive) of the range that was added

beginChange

protected final void beginChange()

Begins a change block. Must be called before any of the next* methods is called. For every beginChange(), there must be a corresponding endChange() call.

beginChange() calls can be nested in a beginChange()/endChange() block.

See Also:

endChange()

endChange

protected final void endChange()

Ends the change block. If the block is the outer-most block for the ObservableList, the Change is constructed and all listeners are notified.

Ending a nested block doesn't fire a notification.

See Also:

beginChange()

addListener

public final void addListener(InvalidationListener listener)

Description copied from interface: Observable

Adds an InvalidationListener which will be notified whenever the Observable becomes invalid. If the same listener is added more than once, then it will be notified more than once. That is, no check is made to ensure uniqueness.

Note that the same actual InvalidationListener instance may be safely registered for different Observables.

The Observable stores a strong reference to the listener which will prevent the listener from being garbage collected and may result in a memory leak. It is recommended to either unregister a listener by calling removeListener after use or to use an instance of WeakInvalidationListener avoid this situation.

Specified by:

addListener in interface Observable

Parameters:

listener - The listener to register

See Also:

Observable.removeListener(InvalidationListener)

removeListener

public final void removeListener(InvalidationListener listener)

Description copied from interface: Observable

Removes the given listener from the list of listeners, that are notified whenever the value of the Observable becomes invalid.

If the given listener has not been previously registered (i.e. it was never added) then this method call is a no-op. If it had been previously added then it will be removed. If it had been added more than once, then only the first occurrence will be removed.

Specified by:

removeListener in interface Observable

Parameters:

listener - The listener to remove

See Also:

Observable.addListener(InvalidationListener)

addListener

public final void addListener(ListChangeListener<? super E> listener)

Description copied from interface: ObservableList

Add a listener to this observable list.

Specified by:

addListener in interface ObservableList<E>

Parameters:

listener - the listener for listening to the list changes

removeListener

public final void removeListener(ListChangeListener<? super E> listener)

Description copied from interface: ObservableList

Tries to remove a listener from this observable list. If the listener is not attached to this list, nothing happens.

Specified by:

removeListener in interface ObservableList<E>

Parameters:

listener - a listener to remove

fireChange

protected final void fireChange(ListChangeListener.Change<? extends E> change)

Notifies all listeners of a change

Parameters:

change - an object representing the change that was done

hasListeners

protected final boolean hasListeners()

Returns true if there are some listeners registered for this list.

Returns:

true if there is a listener for this list

addAll

public boolean addAll(E... elements)

Description copied from interface: ObservableList

A convenience method for var-arg addition of elements.

Specified by:

addAll in interface ObservableList<E>

Parameters:

elements - the elements to add

Returns:

true (as specified by Collection.add(E))

setAll

public boolean setAll(E... elements)

Description copied from interface: ObservableList

Clears the ObservableList and adds all the elements passed as var-args.

Specified by:

setAll in interface ObservableList<E>

Parameters:

elements - the elements to set

Returns:

true (as specified by Collection.add(E))

setAll

public boolean setAll(Collection<? extends E> col)

Description copied from interface: ObservableList

Clears the ObservableList and adds all elements from the collection.

Specified by:

setAll in interface ObservableList<E>

Parameters:

col - the collection with elements that will be added to this observableArrayList

Returns:

true (as specified by Collection.add(E))

removeAll

public boolean removeAll(E... elements)

Description copied from interface: ObservableList

A convenience method for var-arg usage of the removeAll method.

Specified by:

removeAll in interface ObservableList<E>

Parameters:

elements - the elements to be removed

Returns:

true if list changed as a result of this call

retainAll

public boolean retainAll(E... elements)

Description copied from interface: ObservableList

A convenience method for var-arg usage of the retainAll method.

Specified by:

retainAll in interface ObservableList<E>

Parameters:

elements - the elements to be retained

Returns:

true if list changed as a result of this call

remove

public void remove(int from,
                   int to)

Description copied from interface: ObservableList

A simplified way of calling sublist(from, to).clear(). As this is a common operation, ObservableList has this method for convenient usage.

Specified by:

remove in interface ObservableList<E>

Parameters:

from - the start of the range to remove (inclusive)

to - the end of the range to remove (exclusive)