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Eclipse Platform
Release 3.5

org.eclipse.jface.viewers
Class AbstractTreeViewer

java.lang.Object
  extended by 

org.eclipse.jface.viewers.Viewer
      extended by 

org.eclipse.jface.viewers.ContentViewer
          extended by 

org.eclipse.jface.viewers.StructuredViewer
              extended by 

org.eclipse.jface.viewers.ColumnViewer
                  extended by 
org.eclipse.jface.viewers.AbstractTreeViewer
All Implemented Interfaces:
IInputProvider, IInputSelectionProvider, IPostSelectionProvider, ISelectionProvider
Direct Known Subclasses:
TableTreeViewer, TreeViewer

public abstract class AbstractTreeViewer
extends ColumnViewer

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.

As of 3.2, AbstractTreeViewer supports multiple equal elements (each with a different parent chain) in the tree. This support requires that clients enable the element map by calling setUseHashLookup(true).

Content providers for abstract tree viewers must implement one of the interfaces ITreeContentProvider or (as of 3.2, to support multiple equal elements) ITreePathContentProvider.

See Also:
TreeViewer

Nested Class Summary
 
Nested classes/interfaces inherited from class org.eclipse.jface.viewers. StructuredViewer
StructuredViewer.ColorAndFontCollector, StructuredViewer.ColorAndFontCollectorWithProviders
 
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 parentElementOrTreePath, Object childElement)
          Adds the given child element to this viewer as a child of the given parent element.
 void add ( Object parentElementOrTreePath, 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.
protected  void assertContentProviderType ( IContentProvider provider)
          Assert that the content provider is of one of the supported types.
protected  void associate ( Object element, Item item)
          Associates the given element with the given widget.
protected  void buildLabel ( ViewerLabel updateLabel, Object elementOrPath)
          This implementation of buildLabel handles tree paths as well as elements.
 void collapseAll ()
          Collapses all nodes of the viewer's tree, starting with the root.
 void collapseToLevel ( Object elementOrTreePath, int level)
          Collapses the subtree rooted at the given element or tree path 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   ColumnViewerEditor createViewerEditor ()
          This implementation of createViewerEditor() returns null to ensure API backwards compatibility.
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  int doGetColumnCount ()
          Returns the number of columns of this viewer.
protected  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 elementOrTreePath, int level)
          Expands all ancestors of the given element or tree path 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   Item getChild ( Widget widget, int index)
          Get the child for the widget at index.
protected abstract   Item[] getChildren ( Widget widget)
          Returns the SWT child items for the given SWT widget.
  Item[] getChildren ( Widget widget, Object[] elementChildren)
          Deprecated. This method was inadvertently released as API but is not intended to be called by clients.
protected   Widget getColumnViewerOwner (int columnIndex)
          Returns the column widget at the given column index.
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 elementOrTreePath)
          Returns whether the node corresponding to the given element or tree path is expanded or collapsed.
  TreePath[] getExpandedTreePaths ()
          Returns a list of tree paths corresponding to expanded nodes in this viewer's tree, including currently hidden ones that are marked as expanded but are under a collapsed ancestor.
protected   Object[] getFilteredChildren ( Object parentElementOrTreePath)
          Returns the filtered array of children of the given element.
protected   Item getItemAt ( Point point)
          This implementation of getItemAt(Point) returns null to ensure API backwards compatibility.
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   Object getParentElement ( Object elementOrTreePath)
          This method takes a tree path or an element.
protected abstract   Item getParentItem ( Item item)
          Returns the parent item of the given item in the tree, or null if there is no 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 parentElementOrTreePath)
          Returns the children of the given parent without sorting and filtering them.
  ISelection getSelection ()
          This implementation of getSelection() returns an instance of ITreeSelection.
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.
protected   Object[] getSortedChildren ( Object parentElementOrTreePath)
          Returns the sorted and filtered set of children of the given element.
protected   TreePath getTreePathFromItem ( Item item)
          Returns the tree path for the given item.
protected   ViewerRow getViewerRowFromItem ( Widget item)
          Returns a ViewerRow associated with the given row widget.
  Object[] getVisibleExpandedElements ()
          Gets the expanded elements that are visible to the user.
protected  void handleDoubleSelect ( SelectionEvent event)
          Handles a double-click select event from the widget.
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  int indexForElement ( Widget parent, Object element)
          Returns the index where the item should be inserted.
protected  void inputChanged ( Object input, Object oldInput)
          Internal hook method called when the input to this viewer is initially set or subsequently changed.
 void insert ( Object parentElementOrTreePath, Object element, int position)
          Inserts the given element as a new child element of the given parent element at the given position.
protected  void internalAdd ( Widget widget, Object parentElementOrTreePath, Object[] childElements)
          Adds the given child elements to this viewer as children of the given parent element.
protected  void internalCollapseToLevel ( Widget widget, int level)
          Recursively collapses the subtree rooted at the given widget to the given level.
protected   Widget internalExpand ( Object elementOrPath, boolean expand)
          Tries to create a path of tree items for the given element or tree path.
protected  void internalExpandToLevel ( Widget widget, int level)
          Recursively expands the subtree rooted at the given widget to the given level.
protected   Widget[] internalFindItems ( Object parentElementOrTreePath)
          Find the items for the given element of tree path
protected   Widget internalGetWidgetToSelect ( Object elementOrTreePath)
          Returns the widget to be selected for the given element or tree path.
protected  void internalInitializeTree ( Control tree)
          Initializes the tree with root items, expanding to the appropriate level if necessary.
protected  boolean internalIsInputOrEmptyPath ( Object elementOrTreePath)
          Returns true if the given object is either the input or an empty tree path.
protected  void internalRefresh ( Object element)
          Refreshes this viewer starting at the given element.
protected  void internalRefresh ( Object element, boolean updateLabels)
          Refreshes this viewer starting at the given element.
protected  void internalRefresh ( Widget widget, Object element, boolean doStruct, boolean updateLabels)
          Refreshes the tree starting at the given widget.
protected  void internalRemove ( Object[] elementsOrPaths)
          Removes the given elements from this viewer.
protected  void internalRemove ( Object parent, Object[] elements)
          Removes the given elements from this viewer, whenever those elements appear as children of the given parent.
 boolean isExpandable ( Object elementOrTreePath)
          Return whether the tree node representing the given element or path can be expanded.
protected  boolean isSameSelection ( List items, Item[] current)
          Returns true if the given list and array of items refer to the same model elements.
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 elementsOrTreePaths)
          Removes the given element from the viewer.
 void remove ( Object[] elementsOrTreePaths)
          Removes the given elements from this viewer.
 void remove ( Object parent, Object[] elements)
          Removes the given elements from this viewer whenever they appear as children of the given parent element.
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 elementOrTreePath)
          This implementation of reveal() reveals the given element or tree path.
  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 to be used when the input of the viewer is set using StructuredViewer.setInput(Object).
 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 elementOrTreePath, boolean expanded)
          Sets whether the node corresponding to the given element or tree path is expanded or collapsed.
 void setExpandedTreePaths ( TreePath[] treePaths)
          Sets which nodes are expanded in this viewer's tree.
protected abstract  void setSelection ( List items)
          Sets the selection to the given list of items.
protected  void setSelectionToWidget ( ISelection selection, boolean reveal)
          Converts the selection to a List and calls setSelectionToWidget(List, boolean).
protected  void setSelectionToWidget ( List v, boolean reveal)
          This implementation of setSelectionToWidget accepts a list of elements or a list of tree paths.
protected abstract  void showItem ( Item item)
          Shows the given item.
protected  void updateChildren ( Widget widget, Object parent, Object[] elementChildren)
          Deprecated. this is no longer called by the framework
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. ColumnViewer
applyEditorValue, cancelEditing, checkBusy, editElement, getCell, getCellEditors, getCellModifier, getColumnProperties, getColumnViewerEditor, getItem, getLabelProvider, getViewerRow, hookEditingSupport, isBusy, isCellEditorActive, refresh, refresh, setBusy, setCellEditors, setCellModifier, setColumnProperties, setColumnViewerEditor, setLabelProvider, triggerEditorActivationEvent, update
 
Methods inherited from class org.eclipse.jface.viewers. StructuredViewer
addDoubleClickListener, addDragSupport, addDropSupport, addFilter, addOpenListener, addPostSelectionChangedListener, assertElementsNotNull, equals, filter, findItem, findItems, fireDoubleClick, fireOpen, firePostSelectionChanged, getColorAndFontCollector, getComparator, getComparer, getFilters, getRoot, getSorter, handleDispose, handleInvalidSelection, handleLabelProviderChanged, handleOpen, handlePostSelect, handleSelect, hasFilters, internalUpdate, mapElement, needsRefilter, preservingSelection, refresh, refresh, refreshItem, removeDoubleClickListener, removeFilter, removeOpenListener, removePostSelectionChangedListener, resetFilters, setComparator, setComparer, setFilters, setInput, setSelection, setSorter, setUseHashlookup, testFindItem, testFindItems, unmapAllElements, unmapElement, unmapElement, update, updateItem, updateSelection, usingElementMap
 
Methods inherited from class org.eclipse.jface.viewers. ContentViewer
getContentProvider, getInput, getLabelProvider
 
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
 
Methods inherited from interface org.eclipse.jface.viewers. ISelectionProvider
addSelectionChangedListener, removeSelectionChangedListener, setSelection
 

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(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 parentElementOrTreePath,
                
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:
parentElementOrTreePath - the parent element
childElements - the child elements to add

internalFindItems

protected final 
Widget[] internalFindItems(
Object parentElementOrTreePath)
Find the items for the given element of tree path

Parameters:
parentElementOrTreePath - the element or tree path
Returns:
the items for that element
Since:
3.3

internalAdd

protected void internalAdd(
Widget widget,
                           
Object parentElementOrTreePath,
                           
Object[] childElements)
Adds the given child elements to this viewer as children of the given parent element.

EXPERIMENTAL. Not to be used except by JDT. This method was added to support JDT's explorations into grouping by working sets, which requires viewers to support multiple equal elements. See bug 76482 for more details. This support will likely be removed in Eclipse 3.2 in favor of proper support for multiple equal elements.

Parameters:
widget - the widget for the parent element
parentElementOrTreePath - the parent element
childElements - the child elements to add
Since:
3.1

indexForElement

protected int indexForElement(
Widget parent,
                              
Object element)
Returns the index where the item should be inserted.

Parameters:
parent - The parent widget the element will be inserted into.
element - The element to insert.
Returns:
the index of the element

getSortedChildren

protected 
Object[] getSortedChildren(
Object parentElementOrTreePath)
Description copied from class: StructuredViewer
Returns the sorted and filtered set of children of the given element. The resulting array must not be modified, as it may come directly from the model's internal state.

Overrides:
getSortedChildren in class StructuredViewer
Parameters:
parentElementOrTreePath - the parent element
Returns:
a sorted and filtered array of child elements

getFilteredChildren

protected 
Object[] getFilteredChildren(
Object parentElementOrTreePath)
Description copied from class: StructuredViewer
Returns the filtered array of children of the given element. The resulting array must not be modified, as it may come directly from the model's internal state.

Overrides:
getFilteredChildren in class StructuredViewer
Parameters:
parentElementOrTreePath - the parent element
Returns:
a filtered array of child elements

add

public void add(
Object parentElementOrTreePath,
                
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:
parentElementOrTreePath - the parent element or path
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

associate

protected void associate(
Object element,
                         
Item item)
Description copied from class: StructuredViewer
Associates the given element with the given widget. Sets the given item's data to be the element, and maps the element to the item in the element map (if enabled).

Overrides:
associate in class StructuredViewer
Parameters:
element - the element
item - the widget

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 elementOrTreePath,
                            int level)
Collapses the subtree rooted at the given element or tree path to the given level.

Parameters:
elementOrTreePath - the element or tree path
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 searches 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 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

isSameSelection

protected boolean isSameSelection(
List items,
                                  
Item[] current)
Returns true if the given list and array of items refer to the same model elements. Order is unimportant.

This method is not intended to be overridden by subclasses.

Parameters:
items - the list of items
current - the array of items
Returns:
true if the refer to the same elements, false otherwise
Since:
3.1 in TreeViewer, moved to AbstractTreeViewer in 3.3

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 full map 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
element - 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 elementOrTreePath,
                          int level)
Expands all ancestors of the given element or tree path 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:
elementOrTreePath - 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 ALL_LEVELS 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

getChild

protected 
Item getChild(
Widget widget,
                        int index)
Get the child for the widget at index. Note that the default implementation is not very efficient and should be overridden if this class is implemented.

Parameters:
widget - the widget to check
index - the index of the widget
Returns:
Item or null if widget is not a type that can contain items.
Throws:
ArrayIndexOutOfBoundsException - if the index is not valid.
Since:
3.1

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 elementOrTreePath)
Returns whether the node corresponding to the given element or tree path is expanded or collapsed.

Parameters:
elementOrTreePath - 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 no 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 parentElementOrTreePath)
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 ColumnViewer
Parameters:
parentElementOrTreePath - 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

handleDoubleSelect

protected void handleDoubleSelect(
SelectionEvent event)
Description copied from class: StructuredViewer
Handles a double-click select event from the widget.

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

Overrides:
handleDoubleSelect in class StructuredViewer
Parameters:
event - the SWT selection event

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 ColumnViewer
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

internalInitializeTree

protected void internalInitializeTree(
Control tree)
Initializes the tree with root items, expanding to the appropriate level if necessary.

Parameters:
tree - the tree control
Since:
3.3

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 elementOrPath,
                                boolean expand)
Tries to create a path of tree items for the given element or tree path. This method recursively walks up towards the root of the tree and in the case of an element (rather than a tree path) assumes that getParent returns the correct parent of an element.

Parameters:
elementOrPath - the element
expand - true if all nodes on the path should be expanded, and false otherwise
Returns:
Widget

getParentElement

protected 
Object getParentElement(
Object elementOrTreePath)
This method takes a tree path or an element. If the argument is not a tree path, returns the parent of the given element or null if the parent is not known. If the argument is a tree path with more than one segment, returns its parent tree path, otherwise returns null.

Parameters:
elementOrTreePath -
Returns:
the parent element, or parent path, or null
Since:
3.2

internalGetWidgetToSelect

protected 
Widget internalGetWidgetToSelect(
Object elementOrTreePath)
Returns the widget to be selected for the given element or tree path.

Parameters:
elementOrTreePath - the element or tree path to select
Returns:
the widget to be selected, or null if not found
Since:
3.1

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

protected 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

internalRefresh

protected void internalRefresh(
Object element,
                               boolean updateLabels)
Description copied from class: StructuredViewer
Refreshes this viewer starting at the given element. Labels are updated as described in refresh(boolean updateLabels).

The default implementation simply calls internalRefresh(element), ignoring updateLabels.

If this method is overridden to do the actual refresh, then internalRefresh(Object element) should simply call internalRefresh(element, true).

Overrides:
internalRefresh in class StructuredViewer
Parameters:
element - the element
updateLabels - true to update labels for existing elements, false to only update labels as needed, assuming that labels for existing elements are unchanged.

internalRefresh

protected void internalRefresh(
Widget widget,
                               
Object element,
                               boolean doStruct,
                               boolean updateLabels)
Refreshes the tree starting at the given widget.

EXPERIMENTAL. Not to be used except by JDT. This method was added to support JDT's explorations into grouping by working sets, which requires viewers to support multiple equal elements. See bug 76482 for more details. This support will likely be removed in Eclipse 3.2 in favor of proper support for multiple equal elements.

Parameters:
widget - the widget
element - the element
doStruct - true if structural changes are to be picked up, and false if only label provider changes are of interest
updateLabels - true to update labels for existing elements, false to only update labels as needed, assuming that labels for existing elements are unchanged.
Since:
3.1

internalRemove

protected void internalRemove(
Object[] elementsOrPaths)
Removes the given elements from this viewer.

EXPERIMENTAL. Not to be used except by JDT. This method was added to support JDT's explorations into grouping by working sets, which requires viewers to support multiple equal elements. See bug 76482 for more details. This support will likely be removed in Eclipse 3.2 in favor of proper support for multiple equal elements.

Parameters:
elementsOrPaths - the elements or element paths to remove
Since:
3.1

internalRemove

protected void internalRemove(
Object parent,
                              
Object[] elements)
Removes the given elements from this viewer, whenever those elements appear as children of the given parent.

Parameters:
parent - the parent element
elements - the elements to remove
Since:
3.1

isExpandable

public boolean isExpandable(
Object elementOrTreePath)
Return whether the tree node representing the given element or path can be expanded. Clients should query expandability by path if the viewer's content provider is an ITreePathContentProvider.

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

Parameters:
elementOrTreePath - the element or path
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[] elementsOrTreePaths)
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:
elementsOrTreePaths - the elements to remove

remove

public void remove(
Object parent,
                   
Object[] elements)
Removes the given elements from this viewer whenever they appear as children of the given parent element. If the given elements also appear as children of some other parent, the other parent will remain unchanged. 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:
parent - the parent of the elements to remove
elements - the elements to remove
Since:
3.2

remove

public void remove(
Object elementsOrTreePaths)
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:
elementsOrTreePaths - 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 elementOrTreePath)
This implementation of reveal() reveals the given element or tree path.

Specified by:
reveal in class StructuredViewer
Parameters:
elementOrTreePath - 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
Returns:
the item scrolled down to

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
Returns:
the item scrolled up to

setAutoExpandLevel

public void setAutoExpandLevel(int level)
Sets the auto-expand level to be used when the input of the viewer is set using StructuredViewer.setInput(Object). The value 0 means that there is no auto-expand; 1 means that the invisible root element is expanded (since most concrete subclasses do not show the root element, there is usually no practical difference between using the values 0 and 1); 2 means that top-level elements are expanded, but not their children; 3 means that top-level elements are expanded, and their children, but not grandchildren; and so on.

The value ALL_LEVELS means that all subtrees should be expanded.

Note that in previous releases, the Javadoc for this method had an off-by one error. See bug 177669 for details.

Parameters:
level - non-negative level, or ALL_LEVELS 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()

assertContentProviderType

protected void assertContentProviderType(
IContentProvider provider)
Description copied from class: StructuredViewer
Assert that the content provider is of one of the supported types.

Overrides:
assertContentProviderType in class StructuredViewer

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()

setExpandedTreePaths

public void setExpandedTreePaths(
TreePath[] treePaths)
Sets which nodes are expanded in this viewer's tree. The given list contains the tree paths 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 getExpandedTreePaths.

Parameters:
treePaths - the array of expanded tree paths
Since:
3.2
See Also:
getExpandedTreePaths()

setExpandedState

public void setExpandedState(
Object elementOrTreePath,
                             boolean expanded)
Sets whether the node corresponding to the given element or tree path is expanded or collapsed.

Parameters:
elementOrTreePath - 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)
This implementation of setSelectionToWidget accepts a list of elements or a list of tree paths.

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)
Deprecated. this is no longer called by the framework

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

getChildren

public 
Item[] getChildren(
Widget widget,
                          
Object[] elementChildren)
Deprecated. This method was inadvertently released as API but is not intended to be called by clients.

Not to be called by clients. Return the items to be refreshed as part of an update. elementChildren are the new elements.

Parameters:
widget -
elementChildren -
Returns:
Item[]
Since:
3.4

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()
Gets the expanded elements that are visible to the user. An expanded element is only visible if the parent is expanded.

Returns:
the visible expanded elements
Since:
2.0

getTreePathFromItem

protected 
TreePath getTreePathFromItem(
Item item)
Returns the tree path for the given item.

Parameters:
item -
Returns:
TreePath
Since:
3.2

getSelection

public 
ISelection getSelection()
This implementation of getSelection() returns an instance of ITreeSelection.

Specified by:
getSelection in interface ISelectionProvider
Overrides:
getSelection in class StructuredViewer
Returns:
ISelection
Since:
3.2

setSelectionToWidget

protected void setSelectionToWidget(
ISelection selection,
                                    boolean reveal)
Description copied from class: StructuredViewer
Converts the selection to a List and calls setSelectionToWidget(List, boolean). The selection is expected to be an IStructuredSelection of elements. If not, the selection is cleared.

Subclasses do not typically override this method, but implement setSelectionToWidget(List, boolean) instead.

Overrides:
setSelectionToWidget in class StructuredViewer
Parameters:
selection - an IStructuredSelection of elements
reveal - true to reveal the first element in the selection, or false otherwise

getExpandedTreePaths

public 
TreePath[] getExpandedTreePaths()
Returns a list of tree paths 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 tree paths
Since:
3.2
See Also:
setExpandedElements(java.lang.Object[])

insert

public void insert(
Object parentElementOrTreePath,
                   
Object element,
                   int position)
Inserts the given element as a new child element of the given parent element at the given position. If this viewer has a sorter, the position is ignored and the element is inserted at the correct position in the sort order.

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:
parentElementOrTreePath - the parent element, or the tree path to the parent
element - the element
position - a 0-based position relative to the model, or -1 to indicate the last position
Since:
3.2

getColumnViewerOwner

protected 
Widget getColumnViewerOwner(int columnIndex)
Description copied from class: ColumnViewer
Returns the column widget at the given column index.

Specified by:
getColumnViewerOwner in class ColumnViewer
Parameters:
columnIndex - the column index
Returns:
Widget the column widget

getItemAt

protected 
Item getItemAt(
Point point)
This implementation of getItemAt(Point) returns null to ensure API backwards compatibility. Subclasses should override.

Specified by:
getItemAt in class ColumnViewer
Parameters:
point - the widget-relative coordinates
Returns:
the Item at the coordinates or null if there is no item at the given coordinates
Since:
3.3

createViewerEditor

protected 
ColumnViewerEditor createViewerEditor()
This implementation of createViewerEditor() returns null to ensure API backwards compatibility. Subclasses should override.

Specified by:
createViewerEditor in class ColumnViewer
Returns:
the editor, or null if this viewer does not support editing cell contents.
Since:
3.3

doGetColumnCount

protected int doGetColumnCount()
Returns the number of columns of this viewer.

Subclasses should overwrite this method, which has a default implementation (returning 0) for API backwards compatility reasons

Specified by:
doGetColumnCount in class ColumnViewer
Returns:
the number of columns
Since:
3.3

buildLabel

protected void buildLabel(
ViewerLabel updateLabel,
                          
Object elementOrPath)
This implementation of buildLabel handles tree paths as well as elements.

Overrides:
buildLabel in class StructuredViewer
Parameters:
updateLabel - the ViewerLabel to collect the result in
elementOrPath - the element or tree path for which a label should be built
See Also:
StructuredViewer.buildLabel(org.eclipse.jface.viewers.ViewerLabel, java.lang.Object)

internalIsInputOrEmptyPath

protected final boolean internalIsInputOrEmptyPath(
Object elementOrTreePath)
Returns true if the given object is either the input or an empty tree path.

Parameters:
elementOrTreePath - an element which could either be the viewer's input, or a tree path
Returns:
true if the given object is either the input or an empty tree path, false otherwise.
Since:
3.3

getViewerRowFromItem

protected 
ViewerRow getViewerRowFromItem(
Widget item)
Description copied from class: ColumnViewer
Returns a ViewerRow associated with the given row widget. Implementations may re-use the same instance for different row widgets; callers can only use the viewer row locally and until the next call to this method.

Specified by:
getViewerRowFromItem in class ColumnViewer
Parameters:
item - the row widget
Returns:
ViewerRow a viewer row object

Eclipse Platform
Release 3.5

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