Class TreeViewer

  • All Implemented Interfaces:
    IInputProvider, IInputSelectionProvider, IPostSelectionProvider, ISelectionProvider
    Direct Known Subclasses:
    CheckboxTreeViewer, CommonViewer, DiffTreeViewer

    public class TreeViewer
    extends AbstractTreeViewer
    A concrete viewer based on an SWT Tree control.

    This class is not intended to be subclassed outside the viewer framework. It is designed to be instantiated with a pre-existing SWT tree control and configured with a domain-specific content provider, label provider, element filter (optional), and element sorter (optional).

    As of 3.2, TreeViewer 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 tree viewers must implement either the ITreeContentProvider interface, (as of 3.2) the ILazyTreeContentProvider interface, or (as of 3.3) the ILazyTreePathContentProvider. If the content provider is an ILazyTreeContentProvider or an ILazyTreePathContentProvider, the underlying Tree must be created using the SWT.VIRTUAL style bit, the tree viewer will not support sorting or filtering, and hash lookup must be enabled by calling StructuredViewer.setUseHashlookup(boolean).

    Users setting up an editable tree with more than 1 column have to pass the SWT.FULL_SELECTION style bit

    Restriction:
    This class is not intended to be subclassed by clients.
    • Constructor Detail

      • TreeViewer

        public TreeViewer​(Composite parent)
        Creates a tree viewer on a newly-created tree control under the given parent. The tree control is created using the SWT style bits MULTI, H_SCROLL, V_SCROLL, and BORDER. The viewer has no input, no content provider, a default label provider, no sorter, and no filters.
        Parameters:
        parent - the parent control
      • TreeViewer

        public TreeViewer​(Composite parent,
                          int style)
        Creates a tree viewer on a newly-created tree control under the given parent. The tree control is created using the given SWT style bits. The viewer has no input, no content provider, a default label provider, no sorter, and no filters.
        Parameters:
        parent - the parent control
        style - the SWT style bits used to create the tree.
      • TreeViewer

        public TreeViewer​(Tree tree)
        Creates a tree viewer on the given tree control. The viewer has no input, no content provider, a default label provider, no sorter, and no filters.
        Parameters:
        tree - the tree control
    • Method Detail

      • getColumnViewerOwner

        protected Widget getColumnViewerOwner​(int columnIndex)
        Description copied from class: ColumnViewer
        Returns the column widget at the given column index.
        Overrides:
        getColumnViewerOwner in class AbstractTreeViewer
        Parameters:
        columnIndex - the column index
        Returns:
        Widget the column widget
      • getControl

        public Control getControl()
        Description copied from class: Viewer
        Returns the primary control associated with this viewer.
        Specified by:
        getControl in class Viewer
        Returns:
        the SWT control which displays this viewer's content
      • getExpanded

        protected boolean getExpanded​(Item item)
        Description copied from class: AbstractTreeViewer
        Returns whether the given SWT item is expanded or collapsed.
        Specified by:
        getExpanded in class AbstractTreeViewer
        Parameters:
        item - the item
        Returns:
        true if the item is considered expanded and false if collapsed
      • getItemCount

        protected int getItemCount​(Control widget)
        Description copied from class: AbstractTreeViewer
        Returns the number of child items of the given SWT control.
        Specified by:
        getItemCount in class AbstractTreeViewer
        Parameters:
        widget - the control
        Returns:
        the number of children
      • getItemCount

        protected int getItemCount​(Item item)
        Description copied from class: AbstractTreeViewer
        Returns the number of child items of the given SWT item.
        Specified by:
        getItemCount in class AbstractTreeViewer
        Parameters:
        item - the item
        Returns:
        the number of children
      • getLabelProvider

        public IBaseLabelProvider getLabelProvider()
        The tree viewer implementation of this Viewer framework method ensures that the given label provider is an instance of either ITableLabelProvider or ILabelProvider. If it is an ITableLabelProvider, then it provides a separate label text and image for each column. If it is an ILabelProvider, then it provides only the label text and image for the first column, and any remaining columns are blank.
        Overrides:
        getLabelProvider in class ContentViewer
        Returns:
        a label provider
      • getParentItem

        protected Item getParentItem​(Item item)
        Description copied from class: AbstractTreeViewer
        Returns the parent item of the given item in the tree, or null if there is no parent item.
        Specified by:
        getParentItem in class AbstractTreeViewer
        Parameters:
        item - the item
        Returns:
        the parent item, or null if none
      • getSelection

        protected Item[] getSelection​(Control widget)
        Description copied from class: AbstractTreeViewer
        Returns all selected items for the given SWT control.
        Specified by:
        getSelection in class AbstractTreeViewer
        Parameters:
        widget - the control
        Returns:
        the list of selected items
      • getTree

        public Tree getTree()
        Returns this tree viewer's tree control.
        Returns:
        the tree control
      • 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 AbstractTreeViewer
        Parameters:
        control - the control
      • newItem

        protected Item newItem​(Widget parent,
                               int flags,
                               int ix)
        Description copied from class: AbstractTreeViewer
        Creates a new item.
        Specified by:
        newItem in class AbstractTreeViewer
        Parameters:
        parent - the parent widget
        flags - SWT style bits
        ix - if non-negative, indicates the position to insert the item into its parent
        Returns:
        the newly-created item
      • setExpanded

        protected void setExpanded​(Item node,
                                   boolean expand)
        Description copied from class: AbstractTreeViewer
        Sets the expand state of the given item.
        Specified by:
        setExpanded in class AbstractTreeViewer
        Parameters:
        node - the item
        expand - the expand state of the item
      • setSelection

        protected void setSelection​(List<Item> items)
        Description copied from class: AbstractTreeViewer
        Sets the selection to the given list of items.
        Specified by:
        setSelection in class AbstractTreeViewer
        Parameters:
        items - list of items (element type: org.eclipse.swt.widgets.Item)
      • getChild

        protected Item getChild​(Widget widget,
                                int index)
        Description copied from class: AbstractTreeViewer
        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.
        Overrides:
        getChild in class AbstractTreeViewer
        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.
      • 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 AbstractTreeViewer
        Parameters:
        parent - the parent element
        Returns:
        the child elements
      • setChildCount

        public void setChildCount​(Object elementOrTreePath,
                                  int count)
        For a TreeViewer with a tree with the VIRTUAL style bit set, set the number of children of the given element or tree path. To set the number of children of the invisible root of the tree, you can pass the input object or an empty tree path.
        Parameters:
        elementOrTreePath - the element, or tree path
        count -
        Since:
        3.2
      • replace

        public void replace​(Object parentElementOrTreePath,
                            int index,
                            Object element)
        For a TreeViewer with a tree with the VIRTUAL style bit set, replace the given parent's child at index with the given element. If the given parent is this viewer's input or an empty tree path, this will replace the root element at the given index.

        This method should be called by implementers of ILazyTreeContentProvider to populate this viewer.

        Parameters:
        parentElementOrTreePath - the parent of the element that should be updated, or the tree path to that parent
        index - the index in the parent's children
        element - the new element
        Since:
        3.2
        See Also:
        setChildCount(Object, int), ILazyTreeContentProvider, ILazyTreePathContentProvider
      • isExpandable

        public boolean isExpandable​(Object element)
        Description copied from class: AbstractTreeViewer
        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.

        Overrides:
        isExpandable in class AbstractTreeViewer
        Parameters:
        element - the element or path
        Returns:
        true if the tree node representing the given element can be expanded, or false if not
        See Also:
        AbstractTreeViewer.setExpandPreCheckFilters(boolean)
      • getParentElement

        protected Object getParentElement​(Object element)
        Description copied from class: AbstractTreeViewer
        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.
        Overrides:
        getParentElement in class AbstractTreeViewer
        Returns:
        the parent element, or parent path, or null
      • internalAdd

        protected void internalAdd​(Widget widget,
                                   Object parentElement,
                                   Object[] childElements)
        Description copied from class: AbstractTreeViewer
        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. This method cannot be removed without breaking binary backwards compatibility, but should not be called by clients.

        Overrides:
        internalAdd in class AbstractTreeViewer
        Parameters:
        widget - the widget for the parent element
        parentElement - the parent element
        childElements - the child elements to add
      • internalRefreshStruct

        protected void internalRefreshStruct​(Widget widget,
                                             Object element,
                                             boolean updateLabels)
      • mapElement

        protected void mapElement​(Object element,
                                  Widget item)
        Description copied from class: StructuredViewer
        Adds the element item pair to the element map.

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

        Overrides:
        mapElement in class StructuredViewer
        Parameters:
        element - the element
        item - the corresponding widget
      • 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.
        Overrides:
        getViewerRowFromItem in class AbstractTreeViewer
        Parameters:
        item - the row widget
        Returns:
        ViewerRow a viewer row object
      • updatePlus

        protected void updatePlus​(Item item,
                                  Object element)
        Description copied from class: AbstractTreeViewer
        Updates the "+"/"-" icon of the tree node from the given element. It calls isExpandable to determine whether an element is expandable.
        Overrides:
        updatePlus in class AbstractTreeViewer
        Parameters:
        item - the item
        element - the element
      • remove

        public void remove​(Object parentOrTreePath,
                           int index)
        Removes the element at the specified index of the parent. The selection is updated if required.
        Parameters:
        parentOrTreePath - the parent element, the input element, or a tree path to the parent element
        index - child index
        Since:
        3.3
      • setHasChildren

        public void setHasChildren​(Object elementOrTreePath,
                                   boolean hasChildren)
        For a TreeViewer with a tree with the VIRTUAL style bit set, inform the viewer about whether the given element or tree path has children. Avoid calling this method if the number of children has already been set.
        Parameters:
        elementOrTreePath - the element, or tree path
        hasChildren -
        Since:
        3.3
      • disassociate

        protected void disassociate​(Item item)
        Description copied from class: AbstractTreeViewer
        The AbstractTreeViewer implementation of this method also recurses over children of the corresponding element.
        Overrides:
        disassociate in class AbstractTreeViewer
        Parameters:
        item - the widget
      • doGetColumnCount

        protected int doGetColumnCount()
        Description copied from class: AbstractTreeViewer
        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

        Overrides:
        doGetColumnCount in class AbstractTreeViewer
        Returns:
        the number of columns
      • setSelection

        public void setSelection​(ISelection selection,
                                 boolean reveal)
        Sets a new selection for this viewer and optionally makes it visible.

        Currently the reveal parameter is not honored because Tree does not provide an API to only select an item without scrolling it into view

        Overrides:
        setSelection in class StructuredViewer
        Parameters:
        selection - the new selection
        reveal - true if the selection is to be made visible, and false otherwise
      • editElement

        public void editElement​(Object element,
                                int column)
        Description copied from class: ColumnViewer
        Starts editing the given element at the given column index.
        Overrides:
        editElement in class ColumnViewer
        Parameters:
        element - the model element
        column - the column index