net.sourceforge.java.util.gui.jface.viewers
Class TreeViewerContentProvider

java.lang.Object
  net.sourceforge.java.util.gui.jface.viewers.TreeViewerContentProvider

All Implemented Interfaces:

EventListener, IContentProvider, IMutableTreeElementListener, IStructuredContentProvider, ITreeContentProvider

public class TreeViewerContentProvider

extends Object

implements ITreeContentProvider, IMutableTreeElementListener

Provides the data for a JFace TreeViewer instance.

Author:

Sebastian Machhausen

Field Summary

private IMutableTreeElement	root The root element
private TreeViewer	viewer The Viewer that this TreeViewerContentProvider serves

Constructor Summary

TreeViewerContentProvider(TreeViewer viewer, IMutableTreeElement root)
Creates a new TreeViewerContentProvider using the specified root IMutableTreeElement.

Method Summary

void	dispose() Disposes of this content provider.
void	elementAdded(MutableTreeElementEvent event) Called whenever an element was added to the favorites tree.
void	elementRemoved(MutableTreeElementEvent event) Called whenever an element was removed from the favorites tree.
void	elementUpdated(MutableTreeElementEvent event) Called whenever an element was updated in the favorites tree.
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.
Object	getParent(Object element) Returns the parent for the given element, or null indicating that the parent can't be computed.
IMutableTreeElement	getRoot() Gets the root element managed by this TreeViewerContentProvider.
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

Field Detail

viewer

private TreeViewer viewer

The Viewer that this TreeViewerContentProvider serves

root

private IMutableTreeElement root

The root element

Constructor Detail

TreeViewerContentProvider

public TreeViewerContentProvider(TreeViewer viewer,
                                 IMutableTreeElement root)

Creates a new TreeViewerContentProvider using the specified root IMutableTreeElement.

Parameters:

viewer - the TreeViewer that this TreeViewerContentProvider serves

root - the IMutableTreeElement to use as root

Method Detail

getRoot

public IMutableTreeElement getRoot()

Gets the root element managed by this TreeViewerContentProvider.

Returns:

the root element managed by this TreeViewerContentProvider.

getChildren

public Object[] getChildren(Object parentElement)

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)

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

hasChildren

public boolean hasChildren(Object element)

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

dispose

public void dispose()

Disposes of this content provider. This is called by the viewer when it is disposed.

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

Specified by:

dispose in interface IContentProvider

inputChanged

public 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.

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.

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)

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.

Specified by:

getElements in interface IStructuredContentProvider

Parameters:

inputElement - the input element

Returns:

the array of elements to display in the viewer

elementAdded

public void elementAdded(MutableTreeElementEvent event)

Called whenever an element was added to the favorites tree.

Specified by:

elementAdded in interface IMutableTreeElementListener

Parameters:

event - the event triggered

elementRemoved

public void elementRemoved(MutableTreeElementEvent event)

Called whenever an element was removed from the favorites tree.

Specified by:

elementRemoved in interface IMutableTreeElementListener

Parameters:

event - the event triggered

elementUpdated

public void elementUpdated(MutableTreeElementEvent event)

Called whenever an element was updated in the favorites tree.

Specified by:

elementUpdated in interface IMutableTreeElementListener

Parameters:

event - the event triggered