Package org.eclipse.jface.databinding.viewers

Class ObservableListTreeContentProvider<E>

java.lang.Object

org.eclipse.jface.databinding.viewers.ObservableListTreeContentProvider<E>

Type Parameters:

E - type of the values that are provided by this object

All Implemented Interfaces:

IContentProvider, IStructuredContentProvider, ITreeContentProvider

public class ObservableListTreeContentProvider<E>
extends Object
implements ITreeContentProvider

An ITreeContentProvider for use with an AbstractTreeViewer, which uses the provided list factory to obtain the elements of a tree. Object of this class listen for changes to each IObservableList created by the factory, and will insert and remove viewer elements to reflect the observed changes.

Since:

1.2

Restriction:

This class is not intended to be subclassed by clients.

Constructor Summary

Constructors

Constructor	Description
ObservableListTreeContentProvider(IObservableFactory<? super E,? extends IObservableList<E>> listFactory, TreeStructureAdvisor<? super E> structureAdvisor)	Constructs an ObservableListTreeContentProvider using the given list factory.

Method Summary

Modifier and Type	Method	Description
void	dispose()	Disposes of this content provider.
Object[]	getChildren(Object parentElement)	Returns the child elements of the given parent element.
Object[]	getElements(Object inputElement)	Returns the elements to display in the viewer when its input is set to the given element.
IObservableSet<E>	getKnownElements()	Returns the set of elements known to this content provider.
Object	getParent(Object element)	Returns the parent for the given element, or null indicating that the parent can't be computed.
IObservableSet<E>	getRealizedElements()	Returns the set of known elements which have been realized in the viewer.
boolean	hasChildren(Object element)	Returns whether the given element has children.
void	inputChanged(Viewer viewer, Object oldInput, Object newInput)	Notifies this content provider that the given viewer's input has been switched to a different element.

Methods inherited from class java.lang.Object

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

Constructor Detail

ObservableListTreeContentProvider

public ObservableListTreeContentProvider(IObservableFactory<? super E,? extends IObservableList<E>> listFactory,
                                         TreeStructureAdvisor<? super E> structureAdvisor)

Constructs an ObservableListTreeContentProvider using the given list factory. Must be called from the display thread.

Parameters:

listFactory - observable factory that produces an IObservableList of children for a given parent element. Observable lists created by this factory must be on the realm of the current display.

structureAdvisor - an advisor that will be consulted from the implementations of the getParent(Object) and hasChildren(Object) methods, or null if no advisor is available. It is recommended that clients pass a non-null advisor if they can provide additional structural information about the tree.

Method Detail

inputChanged

public void inputChanged(Viewer viewer,
                         Object oldInput,
                         Object newInput)

Description copied from interface: IContentProvider

Notifies this content provider that the given viewer's input has been switched to a different element.

A typical use for this method is registering the content provider as a listener to changes on the new input (using model-specific means), and deregistering the viewer from the old input. In response to these change notifications, the content provider should update the viewer (see the add, remove, update and refresh methods on the viewers).

The viewer should not be updated during this call, as it might be in the process of being disposed.

The default implementation does nothing.

Specified by:

inputChanged in interface IContentProvider

Parameters:

viewer - the viewer

oldInput - the old input element, or null if the viewer did not previously have an input

newInput - the new input element, or null if the viewer does not have an input

getElements

public Object[] getElements(Object inputElement)

Description copied from interface: ITreeContentProvider

Returns the elements to display in the viewer when its input is set to the given element. These elements can be presented as rows in a table, items in a list, etc. The result is not modified by the viewer.

NOTE: The returned array must not contain the given inputElement, since this leads to recursion issues in AbstractTreeViewer (see bug 9262).

Specified by:

getElements in interface IStructuredContentProvider

Specified by:

getElements in interface ITreeContentProvider

Parameters:

inputElement - the input element

Returns:

the array of elements to display in the viewer

hasChildren

public boolean hasChildren(Object element)

Description copied from interface: ITreeContentProvider

Returns whether the given element has children.

Intended as an optimization for when the viewer does not need the actual children. Clients may be able to implement this more efficiently than getChildren.

Specified by:

hasChildren in interface ITreeContentProvider

Parameters:

element - the element

Returns:

true if the given element has children, and false if it has no children

getChildren

public Object[] getChildren(Object parentElement)

Description copied from interface: ITreeContentProvider

Returns the child elements of the given parent element.

The difference between this method and IStructuredContentProvider.getElements is that getElements is called to obtain the tree viewer's root elements, whereas getChildren is used to obtain the children of a given parent element in the tree (including a root).

The result is not modified by the viewer.

Specified by:

getChildren in interface ITreeContentProvider

Parameters:

parentElement - the parent element

Returns:

an array of child elements

getParent

public Object getParent(Object element)

Description copied from interface: ITreeContentProvider

Returns the parent for the given element, or null indicating that the parent can't be computed. In this case the tree-structured viewer can't expand a given node correctly if requested.

Specified by:

getParent in interface ITreeContentProvider

Parameters:

element - the element

Returns:

the parent element, or null if it has none or if the parent cannot be computed

dispose

public void dispose()

Disposes of this content provider. This is called by the viewer when a content provider is replaced, or when the viewer itself is disposed.

The viewer should not be updated during this call, as it is in the process of being disposed.

Note: Data binding content providers become unusable on disposal.

Specified by:

dispose in interface IContentProvider

getKnownElements

public IObservableSet<E> getKnownElements()

Returns the set of elements known to this content provider. Label providers may track this set if they need to be notified about additions before the viewer sees the added element, and notified about removals after the element was removed from the viewer. This is intended for use by label providers, as it will always return the items that need labels.

Returns:

readableSet of items that will need labels

getRealizedElements

public IObservableSet<E> getRealizedElements()

Returns the set of known elements which have been realized in the viewer. Clients may track this set in order to perform custom actions on elements while they are known to be present in the viewer.

Returns:

the set of known elements which have been realized in the viewer.

Since:

1.3