org.eclipse.jface.viewers
Class AbstractTreeViewer

java.lang.Object
  |
  +--org.eclipse.jface.viewers.Viewer
        |
        +--org.eclipse.jface.viewers.ContentViewer
              |
              +--org.eclipse.jface.viewers.StructuredViewer
                    |
                    +--org.eclipse.jface.viewers.AbstractTreeViewer

All Implemented Interfaces:

IInputProvider, IInputSelectionProvider, ISelectionProvider

Direct Known Subclasses:

TableTreeViewer, TreeViewer

public abstract class AbstractTreeViewer

extends StructuredViewer

Abstract base implementation for tree-structure-oriented viewers (trees and table trees).

Nodes in the tree can be in either an expanded or a collapsed state, depending on whether the children on a node are visible. This class introduces public methods for controlling the expanding and collapsing of nodes.

Content providers for abstract tree viewers must implement the ITreeContentProvider interface.

See Also:

TreeViewer, TableTreeViewer

Field Summary

static int

ALL_LEVELS Constant indicating that all levels of the tree should be expanded or collapsed.

Fields inherited from class org.eclipse.jface.viewers.Viewer

WIDGET_DATA_KEY

Constructor Summary

protected

AbstractTreeViewer() Creates an abstract tree viewer.

Method Summary

void	add(Object parentElement, Object childElement) Adds the given child element to this viewer as a child of the given parent element.
void	add(Object parentElement, Object[] childElements) Adds the given child elements to this viewer as children of the given parent element.
protected void	addSelectionListener(Control control, SelectionListener listener) Deprecated.
protected abstract void	addTreeListener(Control control, TreeListener listener) Adds the given SWT tree listener to the given SWT control.
void	addTreeListener(ITreeViewerListener listener) Adds a listener for expand and collapse events in this viewer.
void	collapseAll() Collapses all nodes of the viewer's tree, starting with the root.
void	collapseToLevel(Object element, int level) Collapses the subtree rooted at the given element to the given level.
protected void	createChildren(Widget widget) Creates all children for the given widget.
protected void	createTreeItem(Widget parent, Object element, int index) Creates a single item for the given parent and synchronizes it with the given element.
protected void	disassociate(Item item) The AbstractTreeViewer implementation of this method also recurses over children of the corresponding element.
protected Widget	doFindInputItem(Object element) Returns the widget in this viewer's control which represents the given element if it is the viewer's input.
protected Widget	doFindItem(Object element) Returns the widget in this viewer's control which represent the given element.
protected abstract void	doUpdateItem(Item item, Object element) Copies the attributes of the given element into the given SWT item.
protected void	doUpdateItem(Widget widget, Object element, boolean fullMap) Copies the attributes of the given element into the given SWT item.
void	expandAll() Expands all nodes of the viewer's tree, starting with the root.
void	expandToLevel(int level) Expands the root of the viewer's tree to the given level.
void	expandToLevel(Object element, int level) Expands all ancestors of the given element so that the given element becomes visible in this viewer's tree control, and then expands the subtree rooted at the given element to the given level.
protected void	fireTreeCollapsed(TreeExpansionEvent event) Fires a tree collapsed event.
protected void	fireTreeExpanded(TreeExpansionEvent event) Fires a tree expanded event.
int	getAutoExpandLevel() Returns the auto-expand level.
protected abstract Item[]	getChildren(Widget widget) Returns the SWT child items for the given SWT widget.
protected abstract boolean	getExpanded(Item item) Returns whether the given SWT item is expanded or collapsed.
Object[]	getExpandedElements() Returns a list of elements corresponding to expanded nodes in this viewer's tree, including currently hidden ones that are marked as expanded but are under a collapsed ancestor.
boolean	getExpandedState(Object element) Returns whether the node corresponding to the given element is expanded or collapsed.
protected abstract int	getItemCount(Control control) Returns the number of child items of the given SWT control.
protected abstract int	getItemCount(Item item) Returns the number of child items of the given SWT item.
protected abstract Item[]	getItems(Item item) Returns the child items of the given SWT item.
protected Item	getNextItem(Item item, boolean includeChildren) Returns the item after the given item in the tree, or null if there is no next item.
protected abstract Item	getParentItem(Item item) Returns the parent item of the given item in the tree, or null if there is parent item.
protected Item	getPreviousItem(Item item) Returns the item before the given item in the tree, or null if there is no previous item.
protected Object[]	getRawChildren(Object parent) Returns the children of the given parent without sorting and filtering them.
protected abstract Item[]	getSelection(Control control) Returns all selected items for the given SWT control.
protected List	getSelectionFromWidget() Retrieves the selection, as a List, from the underlying widget.
Object[]	getVisibleExpandedElements() Get the expanded elements that are visible to the user.
protected void	handleTreeCollapse(TreeEvent event) Handles a tree collapse event from the SWT widget.
protected void	handleTreeExpand(TreeEvent event) Handles a tree expand event from the SWT widget.
protected void	hookControl(Control control) Adds event listener hooks to the given control.
protected void	inputChanged(Object input, Object oldInput) Internal hook method called when the input to this viewer is initially set or subsequently changed.
protected void	internalCollapseToLevel(Widget widget, int level) Recursively collapses the subtree rooted at the given widget to the given level.
protected Widget	internalExpand(Object element, boolean expand) Tries to create a path of tree items for the given element.
protected void	internalExpandToLevel(Widget widget, int level) Recursively expands the subtree rooted at the given widget to the given level.
void	internalRefresh(Object element) Refreshes this viewer starting at the given element.
boolean	isExpandable(Object element) Return whether the tree node representing the given element can be expanded.
protected void	labelProviderChanged() Notifies that the label provider has changed.
protected abstract Item	newItem(Widget parent, int style, int index) Creates a new item.
void	remove(Object element) Removes the given element from the viewer.
void	remove(Object[] elements) Removes the given elements from this viewer.
protected abstract void	removeAll(Control control) Removes all items from the given control.
void	removeTreeListener(ITreeViewerListener listener) Removes a listener for expand and collapse events in this viewer.
void	reveal(Object element) Ensures that the given element is visible, scrolling the viewer if necessary.
Item	scrollDown(int x, int y) Scrolls the viewer's control down by one item from the given display-relative coordinates.
Item	scrollUp(int x, int y) Scrolls the viewer's control up by one item from the given display-relative coordinates.
void	setAutoExpandLevel(int level) Sets the auto-expand level.
void	setContentProvider(IContentProvider provider) The AbstractTreeViewer implementation of this method checks to ensure that the content provider is an ITreeContentProvider.
protected abstract void	setExpanded(Item item, boolean expand) Sets the expand state of the given item.
void	setExpandedElements(Object[] elements) Sets which nodes are expanded in this viewer's tree.
void	setExpandedState(Object element, boolean expanded) Sets whether the node corresponding to the given element is expanded or collapsed.
protected abstract void	setSelection(List items) Sets the selection to the given list of items.
protected void	setSelectionToWidget(List v, boolean reveal) Parlays the given list of selected elements into selections on this viewer's control.
protected abstract void	showItem(Item item) Shows the given item.
protected void	updateChildren(Widget widget, Object parent, Object[] elementChildren) Updates the tree items to correspond to the child elements of the given parent element.
protected void	updatePlus(Item item, Object element) Updates the "+"/"-" icon of the tree node from the given element.

Methods inherited from class org.eclipse.jface.viewers.StructuredViewer

addDoubleClickListener, addDragSupport, addDropSupport, addFilter, addOpenListener, addPostSelectionChangedListener, associate, filter, findItem, fireDoubleClick, fireOpen, firePostSelectionChanged, getFilteredChildren, getFilters, getItem, getRoot, getSelection, getSortedChildren, getSorter, handleDoubleSelect, handleInvalidSelection, handleLabelProviderChanged, handleOpen, handlePostSelect, handleSelect, hasFilters, internalRefresh, mapElement, needsRefilter, preservingSelection, refresh, refresh, refresh, refresh, refreshItem, removeDoubleClickListener, removeFilter, removeOpenListener, removePostSelectionChangedListener, resetFilters, setInput, setSelection, setSelectionToWidget, setSorter, setUseHashlookup, testFindItem, unmapAllElements, unmapElement, unmapElement, update, update, updateItem, updateSelection, usingElementMap

Methods inherited from class org.eclipse.jface.viewers.ContentViewer

getContentProvider, getInput, getLabelProvider, handleDispose, setLabelProvider

Methods inherited from class org.eclipse.jface.viewers.Viewer

addHelpListener, addSelectionChangedListener, fireHelpRequested, fireSelectionChanged, getControl, getData, handleHelpRequest, removeHelpListener, removeSelectionChangedListener, setData, setSelection

Methods inherited from class java.lang.Object

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

Field Detail

ALL_LEVELS

public static final int ALL_LEVELS

Constant indicating that all levels of the tree should be expanded or collapsed.

See Also:

expandToLevel(int), collapseToLevel(java.lang.Object, int), Constant Field Values

Constructor Detail

AbstractTreeViewer

protected AbstractTreeViewer()

Creates an abstract tree viewer. The viewer has no input, no content provider, a default label provider, no sorter, no filters, and has auto-expand turned off.

Method Detail

add

public void add(Object parentElement,
                Object[] childElements)

Adds the given child elements to this viewer as children of the given parent element. If this viewer does not have a sorter, the elements are added at the end of the parent's list of children in the order given; otherwise, the elements are inserted at the appropriate positions.

This method should be called (by the content provider) when elements have been added to the model, in order to cause the viewer to accurately reflect the model. This method only affects the viewer, not the model.

Parameters:

parentElement - the parent element

childElements - the child elements to add

add

public void add(Object parentElement,
                Object childElement)

Adds the given child element to this viewer as a child of the given parent element. If this viewer does not have a sorter, the element is added at the end of the parent's list of children; otherwise, the element is inserted at the appropriate position.

This method should be called (by the content provider) when a single element has been added to the model, in order to cause the viewer to accurately reflect the model. This method only affects the viewer, not the model. Note that there is another method for efficiently processing the simultaneous addition of multiple elements.

Parameters:

parentElement - the parent element

childElement - the child element

addSelectionListener

protected void addSelectionListener(Control control,
                                    SelectionListener listener)

Deprecated.

Adds the given SWT selection listener to the given SWT control.

Parameters:

control - the SWT control

listener - the SWT selection listener

addTreeListener

public void addTreeListener(ITreeViewerListener listener)

Adds a listener for expand and collapse events in this viewer. Has no effect if an identical listener is already registered.

Parameters:

listener - a tree viewer listener

addTreeListener

protected abstract void addTreeListener(Control control,
                                        TreeListener listener)

Adds the given SWT tree listener to the given SWT control.

Parameters:

control - the SWT control

listener - the SWT tree listener

collapseAll

public void collapseAll()

Collapses all nodes of the viewer's tree, starting with the root. This method is equivalent to collapseToLevel(ALL_LEVELS).

collapseToLevel

public void collapseToLevel(Object element,
                            int level)

Collapses the subtree rooted at the given element to the given level.

Parameters:

element - the element

level - non-negative level, or ALL_LEVELS to collapse all levels of the tree

createChildren

protected void createChildren(Widget widget)

Creates all children for the given widget.

The default implementation of this framework method assumes that widget.getData() returns the element corresponding to the node. Note: the node is not visually expanded! You may have to call parent.setExpanded(true).

Parameters:

widget - the widget

createTreeItem

protected void createTreeItem(Widget parent,
                              Object element,
                              int index)

Creates a single item for the given parent and synchronizes it with the given element.

Parameters:

parent - the parent widget

element - the element

index - if non-negative, indicates the position to insert the item into its parent

disassociate

protected void disassociate(Item item)

The AbstractTreeViewer implementation of this method also recurses over children of the corresponding element.

Overrides:

disassociate in class StructuredViewer

Parameters:

item - the widget

doFindInputItem

protected Widget doFindInputItem(Object element)

Description copied from class: StructuredViewer

Returns the widget in this viewer's control which represents the given element if it is the viewer's input.

This method is internal to the framework; subclassers should not call this method.

Specified by:

doFindInputItem in class StructuredViewer

Returns:

the corresponding widget, or null if none

doFindItem

protected Widget doFindItem(Object element)

Description copied from class: StructuredViewer

Returns the widget in this viewer's control which represent the given element. This method searchs all the children of the input element.

This method is internal to the framework; subclassers should not call this method.

Specified by:

doFindItem in class StructuredViewer

Returns:

the corresponding widget, or null if none

doUpdateItem

protected abstract void doUpdateItem(Item item,
                                     Object element)

Copies the attributes of the given element into the given SWT item.

Parameters:

item - the SWT item

element - the element

doUpdateItem

protected void doUpdateItem(Widget widget,
                            Object element,
                            boolean fullMap)

Description copied from class: StructuredViewer

Copies the attributes of the given element into the given SWT item. The element map is updated according to the value of fullMap. If fullMap is true then the current mapping from element to widgets is removed and the new mapping is added. If fullmap is false then only the new map gets installed. Installing only the new map is necessary in cases where only the order of elements changes but not the set of elements.

This method is internal to the framework; subclassers should not call this method.

Specified by:

doUpdateItem in class StructuredViewer

Parameters:

widget -

element - the element

fullMap - true if mappings are added and removed, and false if only the new map gets installed

expandAll

public void expandAll()

Expands all nodes of the viewer's tree, starting with the root. This method is equivalent to expandToLevel(ALL_LEVELS).

expandToLevel

public void expandToLevel(int level)

Expands the root of the viewer's tree to the given level.

Parameters:

level - non-negative level, or ALL_LEVELS to expand all levels of the tree

expandToLevel

public void expandToLevel(Object element,
                          int level)

Expands all ancestors of the given element so that the given element becomes visible in this viewer's tree control, and then expands the subtree rooted at the given element to the given level.

Parameters:

element - the element

level - non-negative level, or ALL_LEVELS to expand all levels of the tree

fireTreeCollapsed

protected void fireTreeCollapsed(TreeExpansionEvent event)

Fires a tree collapsed event. Only listeners registered at the time this method is called are notified.

Parameters:

event - the tree expansion event

See Also:

ITreeViewerListener.treeCollapsed(org.eclipse.jface.viewers.TreeExpansionEvent)

fireTreeExpanded

protected void fireTreeExpanded(TreeExpansionEvent event)

Fires a tree expanded event. Only listeners registered at the time this method is called are notified.

Parameters:

event - the tree expansion event

See Also:

ITreeViewerListener.treeExpanded(org.eclipse.jface.viewers.TreeExpansionEvent)

getAutoExpandLevel

public int getAutoExpandLevel()

Returns the auto-expand level.

Returns:

non-negative level, or EXPAND_ALL if all levels of the tree are expanded automatically

See Also:

setAutoExpandLevel(int)

getChildren

protected abstract Item[] getChildren(Widget widget)

Returns the SWT child items for the given SWT widget.

Parameters:

widget - the widget

Returns:

the child items

getExpanded

protected abstract boolean getExpanded(Item item)

Returns whether the given SWT item is expanded or collapsed.

Parameters:

item - the item

Returns:

true if the item is considered expanded and false if collapsed

getExpandedElements

public Object[] getExpandedElements()

Returns a list of elements corresponding to expanded nodes in this viewer's tree, including currently hidden ones that are marked as expanded but are under a collapsed ancestor.

This method is typically used when preserving the interesting state of a viewer; setExpandedElements is used during the restore.

Returns:

the array of expanded elements

See Also:

setExpandedElements(java.lang.Object[])

getExpandedState

public boolean getExpandedState(Object element)

Returns whether the node corresponding to the given element is expanded or collapsed.

Parameters:

element - the element

Returns:

true if the node is expanded, and false if collapsed

getItemCount

protected abstract int getItemCount(Control control)

Returns the number of child items of the given SWT control.

Parameters:

control - the control

Returns:

the number of children

getItemCount

protected abstract int getItemCount(Item item)

Returns the number of child items of the given SWT item.

Parameters:

item - the item

Returns:

the number of children

getItems

protected abstract Item[] getItems(Item item)

Returns the child items of the given SWT item.

Parameters:

item - the item

Returns:

the child items

getNextItem

protected Item getNextItem(Item item,
                           boolean includeChildren)

Returns the item after the given item in the tree, or null if there is no next item.

Parameters:

item - the item

includeChildren - true if the children are considered in determining which item is next, and false if subtrees are ignored

Returns:

the next item, or null if none

getParentItem

protected abstract Item getParentItem(Item item)

Returns the parent item of the given item in the tree, or null if there is parent item.

Parameters:

item - the item

Returns:

the parent item, or null if none

getPreviousItem

protected Item getPreviousItem(Item item)

Returns the item before the given item in the tree, or null if there is no previous item.

Parameters:

item - the item

Returns:

the previous item, or null if none

getRawChildren

protected Object[] getRawChildren(Object parent)

Description copied from class: StructuredViewer

Returns the children of the given parent without sorting and filtering them. The resulting array must not be modified, as it may come directly from the model's internal state.

Returns an empty array if the given parent is null.

Overrides:

getRawChildren in class StructuredViewer

Parameters:

parent - the parent element

Returns:

the child elements

getSelection

protected abstract Item[] getSelection(Control control)

Returns all selected items for the given SWT control.

Parameters:

control - the control

Returns:

the list of selected items

getSelectionFromWidget

protected List getSelectionFromWidget()

Description copied from class: StructuredViewer

Retrieves the selection, as a List, from the underlying widget.

Specified by:

getSelectionFromWidget in class StructuredViewer

Returns:

the list of selected elements

handleTreeCollapse

protected void handleTreeCollapse(TreeEvent event)

Handles a tree collapse event from the SWT widget.

Parameters:

event - the SWT tree event

handleTreeExpand

protected void handleTreeExpand(TreeEvent event)

Handles a tree expand event from the SWT widget.

Parameters:

event - the SWT tree event

hookControl

protected void hookControl(Control control)

Description copied from class: ContentViewer

Adds event listener hooks to the given control.

All subclasses must call this method when their control is first established.

The ContentViewer implementation of this method hooks dispose events for the given control. Subclasses may override if they need to add other control hooks; however, super.hookControl must be invoked.

Overrides:

hookControl in class StructuredViewer

Parameters:

control - the control

inputChanged

protected void inputChanged(Object input,
                            Object oldInput)

Description copied from class: Viewer

Internal hook method called when the input to this viewer is initially set or subsequently changed.

The default implementation does nothing. Subclassers may override this method to do something when a viewer's input is set. A typical use is populate the viewer.

Overrides:

inputChanged in class Viewer

Parameters:

input - the new input of this viewer, or null if none

oldInput - the old input element or null if there was previously no input

internalCollapseToLevel

protected void internalCollapseToLevel(Widget widget,
                                       int level)

Recursively collapses the subtree rooted at the given widget to the given level.

Note that the default implementation of this method does not call setRedraw.

Parameters:

widget - the widget

level - non-negative level, or ALL_LEVELS to collapse all levels of the tree

internalExpand

protected Widget internalExpand(Object element,
                                boolean expand)

Tries to create a path of tree items for the given element. This method recursively walks up towards the root of the tree and assumes that getParent returns the correct parent of an element.

Parameters:

element - the element

expand - true if all nodes on the path should be expanded, and false otherwise

internalExpandToLevel

protected void internalExpandToLevel(Widget widget,
                                     int level)

Recursively expands the subtree rooted at the given widget to the given level.

Note that the default implementation of this method does not call setRedraw.

Parameters:

widget - the widget

level - non-negative level, or ALL_LEVELS to collapse all levels of the tree

internalRefresh

public void internalRefresh(Object element)

Description copied from class: StructuredViewer

Refreshes this viewer starting at the given element.

Specified by:

internalRefresh in class StructuredViewer

Parameters:

element - the element

isExpandable

public boolean isExpandable(Object element)

Return whether the tree node representing the given element can be expanded.

The default implementation of this framework method calls hasChildren on this viewer's content provider. It may be overridden if necessary.

Parameters:

element - the element

Returns:

true if the tree node representing the given element can be expanded, or false if not

labelProviderChanged

protected void labelProviderChanged()

Description copied from class: ContentViewer

Notifies that the label provider has changed.

The ContentViewer implementation of this method calls refresh(). Subclasses may reimplement or extend.

Overrides:

labelProviderChanged in class ContentViewer

newItem

protected abstract Item newItem(Widget parent,
                                int style,
                                int index)

Creates a new item.

Parameters:

parent - the parent widget

style - SWT style bits

index - if non-negative, indicates the position to insert the item into its parent

Returns:

the newly-created item

remove

public void remove(Object[] elements)

Removes the given elements from this viewer. The selection is updated if required.

This method should be called (by the content provider) when elements have been removed from the model, in order to cause the viewer to accurately reflect the model. This method only affects the viewer, not the model.

Parameters:

elements - the elements to remove

remove

public void remove(Object element)

Removes the given element from the viewer. The selection is updated if necessary.

This method should be called (by the content provider) when a single element has been removed from the model, in order to cause the viewer to accurately reflect the model. This method only affects the viewer, not the model. Note that there is another method for efficiently processing the simultaneous removal of multiple elements.

Parameters:

element - the element

removeAll

protected abstract void removeAll(Control control)

Removes all items from the given control.

Parameters:

control - the control

removeTreeListener

public void removeTreeListener(ITreeViewerListener listener)

Removes a listener for expand and collapse events in this viewer. Has no affect if an identical listener is not registered.

Parameters:

listener - a tree viewer listener

reveal

public void reveal(Object element)

Description copied from class: StructuredViewer

Ensures that the given element is visible, scrolling the viewer if necessary. The selection is unchanged.

Specified by:

reveal in class StructuredViewer

Parameters:

element - the element to reveal

scrollDown

public Item scrollDown(int x,
                       int y)

Description copied from class: Viewer

Scrolls the viewer's control down by one item from the given display-relative coordinates. Returns the newly revealed Item, or null if no scrolling occurred or if the viewer doesn't represent an item-based widget.

Overrides:

scrollDown in class Viewer

Parameters:

x - horizontal coordinate

y - vertical coordinate

scrollUp

public Item scrollUp(int x,
                     int y)

Description copied from class: Viewer

Scrolls the viewer's control up by one item from the given display-relative coordinates. Returns the newly revealed Item, or null if no scrolling occurred or if the viewer doesn't represent an item-based widget.

Overrides:

scrollUp in class Viewer

Parameters:

x - horizontal coordinate

y - vertical coordinate

setAutoExpandLevel

public void setAutoExpandLevel(int level)

Sets the auto-expand level. The value 0 means that the root's children are not visible; 1 means that the root is expanded so that its children are visible, but the root's grandchildren are not; and so on. The value EXPAND_ALL means that all subtrees should be expanded.

Parameters:

level - non-negative level, or EXPAND_ALL to expand all levels of the tree

setContentProvider

public void setContentProvider(IContentProvider provider)

The AbstractTreeViewer implementation of this method checks to ensure that the content provider is an ITreeContentProvider.

Overrides:

setContentProvider in class StructuredViewer

Parameters:

provider - the content provider

See Also:

ContentViewer.getContentProvider()

setExpanded

protected abstract void setExpanded(Item item,
                                    boolean expand)

Sets the expand state of the given item.

Parameters:

item - the item

expand - the expand state of the item

setExpandedElements

public void setExpandedElements(Object[] elements)

Sets which nodes are expanded in this viewer's tree. The given list contains the elements that are to be expanded; all other nodes are to be collapsed.

This method is typically used when restoring the interesting state of a viewer captured by an earlier call to getExpandedElements.

Parameters:

elements - the array of expanded elements

See Also:

getExpandedElements()

setExpandedState

public void setExpandedState(Object element,
                             boolean expanded)

Sets whether the node corresponding to the given element is expanded or collapsed.

Parameters:

element - the element

expanded - true if the node is expanded, and false if collapsed

setSelection

protected abstract void setSelection(List items)

Sets the selection to the given list of items.

Parameters:

items - list of items (element type: org.eclipse.swt.widgets.Item)

setSelectionToWidget

protected void setSelectionToWidget(List v,
                                    boolean reveal)

Description copied from class: StructuredViewer

Parlays the given list of selected elements into selections on this viewer's control.

Subclasses should override to set their selection based on the given list of elements.

Specified by:

setSelectionToWidget in class StructuredViewer

Parameters:

v - list of selected elements (element type: Object) or null if the selection is to be cleared

reveal - true if the selection is to be made visible, and false otherwise

showItem

protected abstract void showItem(Item item)

Shows the given item.

Parameters:

item - the item

updateChildren

protected void updateChildren(Widget widget,
                              Object parent,
                              Object[] elementChildren)

Updates the tree items to correspond to the child elements of the given parent element. If null is passed for the children, this method obtains them (only if needed).

Parameters:

widget - the widget

parent - the parent element

elementChildren - the child elements, or null

updatePlus

protected void updatePlus(Item item,
                          Object element)

Updates the "+"/"-" icon of the tree node from the given element. It calls isExpandable to determine whether an element is expandable.

Parameters:

item - the item

element - the element

getVisibleExpandedElements

public Object[] getVisibleExpandedElements()

Get the expanded elements that are visible to the user. An expanded element is only visible if the parent is expanded.

Returns:

Collection of Object

Since:

2.0