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. 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

  • Constructor Details

    • ObservableListBase

      public ObservableListBase()
      Creates a default ObservableListBase.

  • Method Details

    • 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()

    • 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