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org.eclipse.jface.viewers
Class StructuredViewer

java.lang.Object
  org.eclipse.jface.viewers.Viewer
      org.eclipse.jface.viewers.ContentViewer
          org.eclipse.jface.viewers.StructuredViewer

All Implemented Interfaces:

IInputProvider, IInputSelectionProvider, IPostSelectionProvider, ISelectionProvider

Direct Known Subclasses:

AbstractListViewer, AbstractTreeViewer, TableViewer

public abstract class StructuredViewer

extends ContentViewer

implements IPostSelectionProvider

Abstract base implementation for structure-oriented viewers (trees, lists, tables). Supports custom sorting, filtering, and rendering.

Any number of viewer filters can be added to this viewer (using addFilter). When the viewer receives an update, it asks each of its filters if it is out of date, and refilters elements as required.

See Also:

ViewerFilter, ViewerSorter

Field Summary

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

WIDGET_DATA_KEY

Constructor Summary

protected

StructuredViewer() Creates a structured element viewer.

Method Summary

void	addDoubleClickListener(IDoubleClickListener listener) Adds a listener for double-clicks in this viewer.
void	addDragSupport(int operations, Transfer[] transferTypes, DragSourceListener listener) Adds support for dragging items out of this viewer via a user drag-and-drop operation.
void	addDropSupport(int operations, Transfer[] transferTypes, DropTargetListener listener) Adds support for dropping items into this viewer via a user drag-and-drop operation.
void	addFilter(ViewerFilter filter) Adds the given filter to this viewer, and triggers refiltering and resorting of the elements.
void	addOpenListener(IOpenListener listener) Adds a listener for selection-open in this viewer.
void	addPostSelectionChangedListener(ISelectionChangedListener listener) Adds a listener for post selection changes in this selection provider.
protected void	assertElementsNotNull(Object[] elements) Asserts that the given array of elements is itself non- null and contains no null elements.
protected void	associate(Object element, Item item) Associates the given element with the given widget.
protected void	disassociate(Item item) Disassociates the given SWT item from its corresponding element.
protected abstract 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 abstract Widget	doFindItem(Object element) Returns the widget in this viewer's control which represent the given element.
protected abstract void	doUpdateItem(Widget item, Object element, boolean fullMap) Copies the attributes of the given element into the given SWT item.
protected boolean	equals(Object elementA, Object elementB) Compares two elements for equality.
protected Object[]	filter(Object[] elements) Returns the result of running the given elements through the filters.
protected Widget	findItem(Object element) Finds the widget which represents the given element.
protected void	fireDoubleClick(DoubleClickEvent event) Notifies any double-click listeners that a double-click has been received.
protected void	fireOpen(OpenEvent event) Notifies any open event listeners that a open event has been received.
protected void	firePostSelectionChanged(SelectionChangedEvent event) Notifies any post selection listeners that a post selection event has been received.
IElementComparer	getComparer() Returns the comparator to use for comparing elements, or null if none has been set.
protected Object[]	getFilteredChildren(Object parent) Returns the filtered array of children of the given element.
ViewerFilter[]	getFilters() Returns this viewer's filters.
protected Item	getItem(int x, int y) Returns the item at the given display-relative coordinates, or null if there is no item at that location.
protected Object[]	getRawChildren(Object parent) Returns the children of the given parent without sorting and filtering them.
protected Object	getRoot() Returns the root element.
ISelection	getSelection() The StructuredViewer implementation of this method returns the result as an IStructuredSelection.
protected abstract List	getSelectionFromWidget() Retrieves the selection, as a List, from the underlying widget.
protected Object[]	getSortedChildren(Object parent) Returns the sorted and filtered set of children of the given element.
ViewerSorter	getSorter() Returns this viewer's sorter, or null if it does not have one.
protected void	handleDoubleSelect(SelectionEvent event) Handles a double-click select event from the widget.
protected void	handleInvalidSelection(ISelection invalidSelection, ISelection newSelection) Handles an invalid selection.
protected void	handleLabelProviderChanged(LabelProviderChangedEvent event) The StructuredViewer implementation of this ContentViewer method calls update if the event specifies that the label of a given element has changed, otherwise it calls super.
protected void	handleOpen(SelectionEvent event) Handles an open event from the OpenStrategy.
protected void	handlePostSelect(SelectionEvent e) Handles a post select event from the widget.
protected void	handleSelect(SelectionEvent event) Handles a select event from the widget.
protected boolean	hasFilters() Returns whether this viewer has any filters.
protected void	hookControl(Control control) Adds event listener hooks to the given control.
protected abstract 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	mapElement(Object element, Widget item) Adds the element item pair to the element map.
protected boolean	needsRefilter(Object element, String property) Determines whether a change to the given property of the given element would require refiltering and/or resorting.
protected void	preservingSelection(Runnable updateCode) Attempts to preserves the current selection across a run of the given code.
void	refresh() Refreshes this viewer completely with information freshly obtained from this viewer's model.
void	refresh(boolean updateLabels) Refreshes this viewer with information freshly obtained from this viewer's model.
void	refresh(Object element) Refreshes this viewer starting with the given element.
void	refresh(Object element, boolean updateLabels) Refreshes this viewer starting with the given element.
protected void	refreshItem(Widget widget, Object element) Refreshes the given TableItem with the given element.
void	removeDoubleClickListener(IDoubleClickListener listener) Removes the given double-click listener from this viewer.
void	removeFilter(ViewerFilter filter) Removes the given filter from this viewer, and triggers refiltering and resorting of the elements if required.
void	removeOpenListener(IOpenListener listener) Removes the given open listener from this viewer.
void	removePostSelectionChangedListener(ISelectionChangedListener listener) Removes the given listener for post selection changes from this selection provider.
void	resetFilters() Discards this viewer's filters and triggers refiltering and resorting of the elements.
abstract void	reveal(Object element) Ensures that the given element is visible, scrolling the viewer if necessary.
void	setComparer(IElementComparer comparer) Sets the comparator to use for comparing elements, or null to use the default equals and hashCode methods on the elements themselves.
void	setContentProvider(IContentProvider provider) Sets the content provider used by this viewer.
void	setInput(Object input) The ContentViewer implementation of this Viewer method invokes inputChanged on the content provider and then the inputChanged hook method.
void	setSelection(ISelection selection, boolean reveal) Sets a new selection for this viewer and optionally makes it visible.
protected void	setSelectionToWidget(ISelection selection, boolean reveal) Converts the selection to a List and calls setSelectionToWidget(List, boolean).
protected abstract void	setSelectionToWidget(List l, boolean reveal) Parlays the given list of selected elements into selections on this viewer's control.
void	setSorter(ViewerSorter sorter) Sets this viewer's sorter and triggers refiltering and resorting of this viewer's element.
void	setUseHashlookup(boolean enable) Configures whether this structured viewer uses an internal hash table to speeds up the mapping between elements and SWT items.
Widget	testFindItem(Object element) Hook for testing.
protected void	unmapAllElements() Removes all elements from the map.
protected void	unmapElement(Object element) Removes the given element from the internal element to widget map.
protected void	unmapElement(Object element, Widget item) Removes the given association from the internal element to widget map.
void	update(Object[] elements, String[] properties) Updates the given elements' presentation when one or more of their properties change.
void	update(Object element, String[] properties) Updates the given element's presentation when one or more of its properties changes.
protected void	updateItem(Widget widget, Object element) Copies attributes of the given element into the given widget.
protected void	updateSelection(ISelection selection) Updates the selection of this viewer.
protected boolean	usingElementMap() Returns whether this structured viewer is configured to use an internal map to speed up the mapping between elements and SWT items.

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

getContentProvider, getInput, getLabelProvider, handleDispose, labelProviderChanged, setLabelProvider

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

addHelpListener, addSelectionChangedListener, fireHelpRequested, fireSelectionChanged, getControl, getData, handleHelpRequest, inputChanged, removeHelpListener, removeSelectionChangedListener, scrollDown, scrollUp, 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

Constructor Detail

StructuredViewer

protected StructuredViewer()

Creates a structured element viewer. The viewer has no input, no content provider, a default label provider, no sorter, and no filters.

Method Detail

addDoubleClickListener

public void addDoubleClickListener(IDoubleClickListener listener)

Adds a listener for double-clicks in this viewer. Has no effect if an identical listener is already registered.

Parameters:

listener - a double-click listener

addOpenListener

public void addOpenListener(IOpenListener listener)

Adds a listener for selection-open in this viewer. Has no effect if an identical listener is already registered.

Parameters:

listener - a double-click listener

addPostSelectionChangedListener

public void addPostSelectionChangedListener(ISelectionChangedListener listener)

Description copied from interface: IPostSelectionProvider

Adds a listener for post selection changes in this selection provider. Has no effect if an identical listener is already registered.

Specified by:

addPostSelectionChangedListener in interface IPostSelectionProvider

Parameters:

listener - a selection changed listener

addDragSupport

public void addDragSupport(int operations,
                           Transfer[] transferTypes,
                           DragSourceListener listener)

Adds support for dragging items out of this viewer via a user drag-and-drop operation.

Parameters:

operations - a bitwise OR of the supported drag and drop operation types ( DROP_COPY,DROP_LINK, and DROP_MOVE)

transferTypes - the transfer types that are supported by the drag operation

listener - the callback that will be invoked to set the drag data and to cleanup after the drag and drop operation finishes

See Also:

DND

addDropSupport

public void addDropSupport(int operations,
                           Transfer[] transferTypes,
                           DropTargetListener listener)

Adds support for dropping items into this viewer via a user drag-and-drop operation.

Parameters:

operations - a bitwise OR of the supported drag and drop operation types ( DROP_COPY,DROP_LINK, and DROP_MOVE)

transferTypes - the transfer types that are supported by the drop operation

listener - the callback that will be invoked after the drag and drop operation finishes

See Also:

DND

addFilter

public void addFilter(ViewerFilter filter)

Adds the given filter to this viewer, and triggers refiltering and resorting of the elements.

Parameters:

filter - a viewer filter

assertElementsNotNull

protected void assertElementsNotNull(Object[] elements)

Asserts that the given array of elements is itself non- null and contains no null elements.

Parameters:

elements - the array to check

associate

protected void associate(Object element,
                         Item item)

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).

Parameters:

element - the element

item - the widget

disassociate

protected void disassociate(Item item)

Disassociates the given SWT item from its corresponding element. Sets the item's data to null and removes the element from the element map (if enabled).

Parameters:

item - the widget

doFindInputItem

protected abstract Widget doFindInputItem(Object element)

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.

Parameters:

element -

Returns:

the corresponding widget, or null if none

doFindItem

protected abstract Widget doFindItem(Object element)

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.

Parameters:

element -

Returns:

the corresponding widget, or null if none

doUpdateItem

protected abstract void doUpdateItem(Widget item,
                                     Object element,
                                     boolean fullMap)

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.

Parameters:

item -

element - element

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

equals

protected boolean equals(Object elementA,
                         Object elementB)

Compares two elements for equality. Uses the element comparer if one has been set, otherwise uses the default equals method on the elements themselves.

Parameters:

elementA - the first element

elementB - the second element

Returns:

whether elementA is equal to elementB

filter

protected Object[] filter(Object[] elements)

Returns the result of running the given elements through the filters.

Parameters:

elements - the elements to filter

Returns:

only the elements which all filters accept

findItem

protected final Widget findItem(Object element)

Finds the widget which represents the given element.

The default implementation of this method tries first to find the widget for the given element assuming that it is the viewer's input; this is done by calling doFindInputItem. If it is not found there, it is looked up in the internal element map provided that this feature has been enabled. If the element map is disabled, the widget is found via doFindInputItem.

Parameters:

element - the element

Returns:

the corresponding widget, or null if none

fireDoubleClick

protected void fireDoubleClick(DoubleClickEvent event)

Notifies any double-click listeners that a double-click has been received. Only listeners registered at the time this method is called are notified.

Parameters:

event - a double-click event

See Also:

IDoubleClickListener.doubleClick(org.eclipse.jface.viewers.DoubleClickEvent)

fireOpen

protected void fireOpen(OpenEvent event)

Notifies any open event listeners that a open event has been received. Only listeners registered at the time this method is called are notified.

Parameters:

event - a double-click event

See Also:

IOpenListener.open(OpenEvent)

firePostSelectionChanged

protected void firePostSelectionChanged(SelectionChangedEvent event)

Notifies any post selection listeners that a post selection event has been received. Only listeners registered at the time this method is called are notified.

Parameters:

event - a selection changed event

See Also:

addPostSelectionChangedListener(ISelectionChangedListener)

getComparer

public IElementComparer getComparer()

Returns the comparator to use for comparing elements, or null if none has been set.

Returns:

IElementComparer the comparator to use for comparing elements or null

getFilteredChildren

protected Object[] getFilteredChildren(Object parent)

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.

Parameters:

parent - the parent element

Returns:

a filtered array of child elements

getFilters

public ViewerFilter[] getFilters()

Returns this viewer's filters.

Returns:

an array of viewer filters

getItem

protected Item getItem(int x,
                       int y)

Returns the item at the given display-relative coordinates, or null if there is no item at that location.

The default implementation of this method returns null.

Parameters:

x - horizontal coordinate

y - vertical coordinate

Returns:

the item, or null if there is no item at the given coordinates

getRawChildren

protected Object[] getRawChildren(Object parent)

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.

Parameters:

parent - the parent element

Returns:

the child elements

getRoot

protected Object getRoot()

Returns the root element.

The default implementation of this framework method forwards to getInput. Override if the root element is different from the viewer's input element.

Returns:

the root element, or null if none

getSelection

public ISelection getSelection()

The StructuredViewer implementation of this method returns the result as an IStructuredSelection.

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

Specified by:

getSelection in interface ISelectionProvider

Specified by:

getSelection in class Viewer

Returns:

ISelection

getSelectionFromWidget

protected abstract List getSelectionFromWidget()

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

Returns:

the list of selected elements

getSortedChildren

protected Object[] getSortedChildren(Object parent)

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.

Parameters:

parent - the parent element

Returns:

a sorted and filtered array of child elements

getSorter

public ViewerSorter getSorter()

Returns this viewer's sorter, or null if it does not have one.

Returns:

a viewer sorter, or null if none

handleDoubleSelect

protected void handleDoubleSelect(SelectionEvent event)

Handles a double-click select event from the widget.

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

Parameters:

event - the SWT selection event

handleOpen

protected void handleOpen(SelectionEvent event)

Handles an open event from the OpenStrategy.

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

Parameters:

event - the SWT selection event

handleInvalidSelection

protected void handleInvalidSelection(ISelection invalidSelection,
                                      ISelection newSelection)

Handles an invalid selection.

This framework method is called if a model change picked up by a viewer results in an invalid selection. For instance if an element contained in the selection has been removed from the viewer, the viewer is free to either remove the element from the selection or to pick another element as its new selection. The default implementation of this method calls updateSelection. Subclasses may override it to implement a different strategy for picking a new selection when the old selection becomes invalid.

Parameters:

invalidSelection - the selection before the viewer was updated

newSelection - the selection after the update, or null if none

handleLabelProviderChanged

protected void handleLabelProviderChanged(LabelProviderChangedEvent event)

The StructuredViewer implementation of this ContentViewer method calls update if the event specifies that the label of a given element has changed, otherwise it calls super. Subclasses may reimplement or extend.

Overrides:

handleLabelProviderChanged in class ContentViewer

Parameters:

event - the event that generated this update

handleSelect

protected void handleSelect(SelectionEvent event)

Handles a select event from the widget.

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

Parameters:

event - the SWT selection event

handlePostSelect

protected void handlePostSelect(SelectionEvent e)

Handles a post select event from the widget.

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

Parameters:

e - the SWT selection 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 ContentViewer

Parameters:

control - the control

hasFilters

protected boolean hasFilters()

Returns whether this viewer has any filters.

Returns:

boolean

internalRefresh

protected abstract void internalRefresh(Object element)

Refreshes this viewer starting at the given element.

Parameters:

element - the element

internalRefresh

protected void internalRefresh(Object element,
                               boolean updateLabels)

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).

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.

Since:

2.0

mapElement

protected void mapElement(Object element,
                          Widget item)

Adds the element item pair to the element map.

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

Parameters:

element - the element

item - the corresponding widget

needsRefilter

protected boolean needsRefilter(Object element,
                                String property)

Determines whether a change to the given property of the given element would require refiltering and/or resorting.

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

Parameters:

element - the element

property - the property

Returns:

true if refiltering is required, and false otherwise

preservingSelection

protected void preservingSelection(Runnable updateCode)

Attempts to preserves the current selection across a run of the given code.

The default implementation of this method:

• discovers the old selection (via getSelection)
• runs the given runnable
• attempts to restore the old selection (using setSelectionToWidget
• rediscovers the resulting selection (via getSelection)
• calls handleInvalidSelection if the selection did not take
• calls postUpdateHook

Parameters:

updateCode - the code to run

refresh

public void refresh()

Description copied from class: Viewer

Refreshes this viewer completely with information freshly obtained from this viewer's model.

Specified by:

refresh in class Viewer

refresh

public void refresh(boolean updateLabels)

Refreshes this viewer with information freshly obtained from this viewer's model. If updateLabels is true then labels for otherwise unaffected elements are updated as well. Otherwise, it assumes labels for existing elements are unchanged, and labels are only obtained as needed (for example, for new elements).

Calling refresh(true) has the same effect as refresh().

Note that the implementation may still obtain labels for existing elements even if updateLabels is false. The intent is simply to allow optimization where possible.

Parameters:

updateLabels - true to update labels for existing elements, false to only update labels as needed, assuming that labels for existing elements are unchanged.

Since:

2.0

refresh

public void refresh(Object element)

Refreshes this viewer starting with the given element.

Unlike the update methods, this handles structural changes to the given element (e.g. addition or removal of children). If only the given element needs updating, it is more efficient to use the update methods.

Parameters:

element - the element

refresh

public void refresh(Object element,
                    boolean updateLabels)

Refreshes this viewer starting with the given element. Labels are updated as described in refresh(boolean updateLabels).

Unlike the update methods, this handles structural changes to the given element (e.g. addition or removal of children). If only the given element needs updating, it is more efficient to use the update methods.

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.

Since:

2.0

refreshItem

protected final void refreshItem(Widget widget,
                                 Object element)

Refreshes the given TableItem with the given element. Calls doUpdateItem(..., false).

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

Parameters:

widget -

element -

removeOpenListener

public void removeOpenListener(IOpenListener listener)

Removes the given open listener from this viewer. Has no affect if an identical listener is not registered.

Parameters:

listener - a double-click listener

removePostSelectionChangedListener

public void removePostSelectionChangedListener(ISelectionChangedListener listener)

Description copied from interface: IPostSelectionProvider

Removes the given listener for post selection changes from this selection provider. Has no affect if an identical listener is not registered.

Specified by:

removePostSelectionChangedListener in interface IPostSelectionProvider

Parameters:

listener - a selection changed listener

removeDoubleClickListener

public void removeDoubleClickListener(IDoubleClickListener listener)

Removes the given double-click listener from this viewer. Has no affect if an identical listener is not registered.

Parameters:

listener - a double-click listener

removeFilter

public void removeFilter(ViewerFilter filter)

Removes the given filter from this viewer, and triggers refiltering and resorting of the elements if required. Has no effect if the identical filter is not registered.

Parameters:

filter - a viewer filter

resetFilters

public void resetFilters()

Discards this viewer's filters and triggers refiltering and resorting of the elements.

reveal

public abstract void reveal(Object element)

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

Parameters:

element - the element to reveal

setContentProvider

public void setContentProvider(IContentProvider provider)

Description copied from class: ContentViewer

Sets the content provider used by this viewer.

The ContentViewer implementation of this method records the content provider in an internal state variable. Overriding this method is generally not required; however, if overriding in a subclass, super.setContentProvider must be invoked.

Overrides:

setContentProvider in class ContentViewer

Parameters:

provider - the content provider

See Also:

ContentViewer.getContentProvider()

setInput

public final void setInput(Object input)

Description copied from class: ContentViewer

The ContentViewer implementation of this Viewer method invokes inputChanged on the content provider and then the inputChanged hook method. This method fails if this viewer does not have a content provider. Subclassers are advised to override inputChanged rather than this method, but may extend this method if required.

Overrides:

setInput in class ContentViewer

setSelection

public void setSelection(ISelection selection,
                         boolean reveal)

Description copied from class: Viewer

Sets a new selection for this viewer and optionally makes it visible.

Subclasses must implement this method.

Specified by:

setSelection in class Viewer

Parameters:

selection - the new selection

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

setSelectionToWidget

protected abstract void setSelectionToWidget(List l,
                                             boolean reveal)

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.

Parameters:

l - 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

setSelectionToWidget

protected void setSelectionToWidget(ISelection selection,
                                    boolean reveal)

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.

Parameters:

selection - an IStructuredSelection of elements

reveal - true to reveal the first element in the selection, or false otherwise

setSorter

public void setSorter(ViewerSorter sorter)

Sets this viewer's sorter and triggers refiltering and resorting of this viewer's element. Passing null turns sorting off.

Parameters:

sorter - a viewer sorter, or null if none

setUseHashlookup

public void setUseHashlookup(boolean enable)

Configures whether this structured viewer uses an internal hash table to speeds up the mapping between elements and SWT items. This must be called before the viewer is given an input (via setInput).

Parameters:

enable - true to enable hash lookup, and false to disable it

setComparer

public void setComparer(IElementComparer comparer)

Sets the comparator to use for comparing elements, or null to use the default equals and hashCode methods on the elements themselves.

Parameters:

comparer - the comparator to use for comparing elements or null

testFindItem

public Widget testFindItem(Object element)

Hook for testing.

Parameters:

element -

Returns:

Widget

unmapAllElements

protected void unmapAllElements()

Removes all elements from the map.

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

unmapElement

protected void unmapElement(Object element)

Removes the given element from the internal element to widget map. Does nothing if mapping is disabled. If mapping is enabled, the given element must be present.

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

Parameters:

element - the element

unmapElement

protected void unmapElement(Object element,
                            Widget item)

Removes the given association from the internal element to widget map. Does nothing if mapping is disabled, or if the given element does not map to the given item.

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

Parameters:

element - the element

item - the item to unmap

Since:

2.0

update

public void update(Object[] elements,
                   String[] properties)

Updates the given elements' presentation when one or more of their properties change. Only the given elements are updated.

This does not handle structural changes (e.g. addition or removal of elements), and does not update any other related elements (e.g. child elements). To handle structural changes, use the refresh methods instead.

This should be called when an element has changed in the model, in order to have the viewer accurately reflect the model. This method only affects the viewer, not the model.

Specifying which properties are affected may allow the viewer to optimize the update. For example, if the label provider is not affected by changes to any of these properties, an update may not actually be required. Specifing properties as null forces a full update of the given elements.

If the viewer has a sorter which is affected by a change to one of the properties, the elements' positions are updated to maintain the sort order.

If the viewer has a filter which is affected by a change to one of the properties, elements may appear or disappear if the change affects whether or not they are filtered out.

Parameters:

elements - the elements

properties - the properties that have changed, or null to indicate unknown

update

public void update(Object element,
                   String[] properties)

Updates the given element's presentation when one or more of its properties changes. Only the given element is updated.

This does not handle structural changes (e.g. addition or removal of elements), and does not update any other related elements (e.g. child elements). To handle structural changes, use the refresh methods instead.

This should be called when an element has changed in the model, in order to have the viewer accurately reflect the model. This method only affects the viewer, not the model.

Specifying which properties are affected may allow the viewer to optimize the update. For example, if the label provider is not affected by changes to any of these properties, an update may not actually be required. Specifing properties as null forces a full update of the element.

If the viewer has a sorter which is affected by a change to one of the properties, the element's position is updated to maintain the sort order.

If the viewer has a filter which is affected by a change to one of the properties, the element may appear or disappear if the change affects whether or not the element is filtered out.

Parameters:

element - the element

properties - the properties that have changed, or null to indicate unknown

updateItem

protected final void updateItem(Widget widget,
                                Object element)

Copies attributes of the given element into the given widget.

This method is internal to the framework; subclassers should not call this method. Calls doUpdateItem(widget, element, true).

Parameters:

widget - the widget

element - the element

updateSelection

protected void updateSelection(ISelection selection)

Updates the selection of this viewer.

This framework method should be called when the selection in the viewer widget changes.

The default implementation of this method notifies all selection change listeners recorded in an internal state variable. Overriding this method is generally not required; however, if overriding in a subclass, super.updateSelection must be invoked.

Parameters:

selection - the selection, or null if none

usingElementMap

protected boolean usingElementMap()

Returns whether this structured viewer is configured to use an internal map to speed up the mapping between elements and SWT items.

The default implementation of this framework method checks whether the internal map has been initialized.

Returns:

true if the element map is enabled, and false if disabled