javax.swing
Class JTree

java.lang.Object
  |
  +--java.awt.Component
        |
        +--java.awt.Container
              |
              +--javax.swing.JComponent
                    |
                    +--javax.swing.JTree
All Implemented Interfaces:
Accessible, ImageObserver, MenuContainer, Scrollable, Serializable
public class JTree
extends JComponent
implements Scrollable, Accessible

A control that displays a set of hierarchical data as an outline. You can find task-oriented documentation and examples of using trees in How to Use Trees, a section in The Java Tutorial.

A specific node in a tree can be identified either by a TreePath (an object that encapsulates a node and all of its ancestors), or by its display row, where each row in the display area displays one node. An expanded node is a non-leaf node (as identified by TreeModel.isLeaf(node) returning false) that will displays its children when all its ancestors are expanded. A collapsed node is one which hides them. A hidden node is one which is under a collapsed ancestor. All of a viewable nodes parents are expanded, but may or may not be displayed. A displayed node is both viewable and in the display area, where it can be seen.

The following JTree methods use "visible" to mean "displayed":

  • isRootVisible()
  • setRootVisible()
  • scrollPathToVisible()
  • scrollRowToVisible()
  • getVisibleRowCount()
  • setVisibleRowCount()

The next group of JTree methods use "visible" to mean "viewable" (under an expanded parent):

  • isVisible()
  • makeVisible()

If you are interested in knowing when the selection changes implement the TreeSelectionListener interface and add the instance using the method addTreeSelectionListener. valueChanged will be invoked when the selection changes, that is if the user clicks twice on the same node valueChanged will only be invoked once.

If you are interested in detecting either double-click events or when a user clicks on a node, regardless of whether or not it was selected, we recommend you do the following:

 final JTree tree = ...;

 MouseListener ml = new MouseAdapter() {
     public void mousePressed(MouseEvent e) {
         int selRow = tree.getRowForLocation(e.getX(), e.getY());
         TreePath selPath = tree.getPathForLocation(e.getX(), e.getY());
         if(selRow != -1) {
             if(e.getClickCount() == 1) {
                 mySingleClick(selRow, selPath);
             }
             else if(e.getClickCount() == 2) {
                 myDoubleClick(selRow, selPath);
             }
         }
     }
 };
 tree.addMouseListener(ml);
 
NOTE: This example obtains both the path and row, but you only need to get the one you're interested in.

To use JTree to display compound nodes (for example, nodes containing both a graphic icon and text), subclass TreeCellRenderer and use setCellRenderer(javax.swing.tree.TreeCellRenderer) to tell the tree to use it. To edit such nodes, subclass TreeCellEditor and use setCellEditor(javax.swing.tree.TreeCellEditor).

Like all JComponent classes, you can use InputMap and ActionMap to associate an Action object with a KeyStroke and execute the action under specified conditions.

For the keyboard keys used by this component in the standard Look and Feel (L&F) renditions, see the JTree key assignments.

Warning: Serialized objects of this class will not be compatible with future Swing releases. The current serialization support is appropriate for short term storage or RMI between applications running the same version of Swing. As of 1.4, support for long term storage of all JavaBeansTM has been added to the java.beans package. Please see XMLEncoder.

 

Nested Class Summary

protected  class JTree.AccessibleJTree
    This class implements accessibility support for the JTree class.
static class JTree.DynamicUtilTreeNode
    DynamicUtilTreeNode can wrap vectors/hashtables/arrays/strings and create the appropriate children tree nodes as necessary.
protected static class JTree.EmptySelectionModel
    EmptySelectionModel is a TreeSelectionModel that does not allow anything to be selected.
protected  class JTree.TreeModelHandler
    Listens to the model and updates the expandedState accordingly when nodes are removed, or changed.
protected  class JTree.TreeSelectionRedirector
    Handles creating a new TreeSelectionEvent with the JTree as the source and passing it off to all the listeners.
 
Nested classes inherited from class javax.swing.JComponent
 
Nested classes inherited from class java.awt.Container
 
Nested classes inherited from class java.awt.Component
Component.BltBufferStrategy, Component.FlipBufferStrategy
 

 

Field Summary

static String ANCHOR_SELECTION_PATH_PROPERTY
    Bound property name for anchor selection path.
static String CELL_EDITOR_PROPERTY
    Bound property name for cellEditor.
static String CELL_RENDERER_PROPERTY
    Bound property name for cellRenderer.
protected  TreeCellEditor cellEditor
    Editor for the entries.
protected  TreeCellRenderer cellRenderer
    The cell used to draw nodes.
protected  boolean editable
    Is the tree editable? Default is false.
static String EDItable_PROPERTY
    Bound property name for editable.
static String EXPANDS_SELECTED_PATHS_PROPERTY
    Bound property name for expands selected paths property
static String INVOKES_STOP_CELL_EDITING_PROPERTY
    Bound property name for messagesStopCellEditing.
protected  boolean invokesStopCellEditing
    If true, when editing is to be stopped by way of selection changing, data in tree changing or other means stopCellEditing is invoked, and changes are saved.
static String LARGE_MODEL_PROPERTY
    Bound property name for largeModel.
protected  boolean largeModel
    Is this tree a large model? This is a code-optimization setting.
static String LEAD_SELECTION_PATH_PROPERTY
    Bound property name for leadSelectionPath.
static String ROOT_VISIBLE_PROPERTY
    Bound property name for rootVisible.
protected  boolean rootVisible
    True if the root node is displayed, false if its children are the highest visible nodes.
static String ROW_HEIGHT_PROPERTY
    Bound property name for rowHeight.
protected  int rowHeight
    Height to use for each display row.
static String SCROLLS_ON_EXPAND_PROPERTY
    Bound property name for scrollsOnExpand.
protected  boolean scrollsOnExpand
    If true, when a node is expanded, as many of the descendants are scrolled to be visible.
static String SELECTION_MODEL_PROPERTY
    Bound property name for selectionModel.
protected  TreeSelectionModel selectionModel
    Models the set of selected nodes in this tree.
protected  JTree.TreeSelectionRedirector selectionRedirector
    Creates a new event and passed it off the selectionListeners.
static String SHOWS_ROOT_HANDLES_PROPERTY
    Bound property name for showsRootHandles.
protected  boolean showsRootHandles
    True if handles are displayed at the topmost level of the tree.
static String TOGGLE_CLICK_COUNT_PROPERTY
    Bound property name for toggleClickCount.
protected  int toggleClickCount
    Number of mouse clicks before a node is expanded.
static String TREE_MODEL_PROPERTY
    Bound property name for treeModel.
protected  TreeModel treeModel
    The model that defines the tree displayed by this object.
protected  TreeModelListener treeModelListener
    Updates the expandedState.
static String VISIBLE_ROW_COUNT_PROPERTY
    Bound property name for visibleRowCount.
protected  int visibleRowCount
    Number of rows to make visible at one time.
 
Fields inherited from class javax.swing.JComponent
accessibleContext, listenerList, TOOL_TIP_TEXT_KEY, ui, UNDEFINED_CONDITION, WHEN_ANCESTOR_OF_FOCUSED_COMPONENT, WHEN_FOCUSED, WHEN_IN_FOCUSED_WINDOW
 
Fields inherited from class java.awt.Component
BOTTOM_ALIGNMENT, CENTER_ALIGNMENT, LEFT_ALIGNMENT, RIGHT_ALIGNMENT, TOP_ALIGNMENT
 
Fields inherited from interface java.awt.image.ImageObserver
ABORT, ALLBITS, ERROR, FRAMEBITS, HEIGHT, PROPERTIES, SOMEBITS, WIDTH
 

 

Constructor Summary

JTree()
    Returns a JTree with a sample model.
JTree(Hashtable value)
    Returns a JTree created from a Hashtable which does not display with root.
JTree(Object[] value)
    Returns a JTree with each element of the specified array as the child of a new root node which is not displayed.
JTree(TreeModel newModel)
    Returns an instance of JTree which displays the root node -- the tree is created using the specified data model.
JTree(TreeNode root)
    Returns a JTree with the specified TreeNode as its root, which displays the root node.
JTree(TreeNode root, boolean asksAllowsChildren)
    Returns a JTree with the specified TreeNode as its root, which displays the root node and which decides whether a node is a leaf node in the specified manner.
JTree(Vector value)
    Returns a JTree with each element of the specified Vector as the child of a new root node which is not displayed.
 

 

Method Summary

 void addSelectionInterval(int index0, int index1)
    Adds the paths between index0 and index1, inclusive, to the selection.
 void addSelectionPath(TreePath path)
    Adds the node identified by the specified TreePath to the current selection.
 void addSelectionPaths(TreePath[] paths)
    Adds each path in the array of paths to the current selection.
 void addSelectionRow(int row)
    Adds the path at the specified row to the current selection.
 void addSelectionRows(int[] rows)
    Adds the paths at each of the specified rows to the current selection.
 void addTreeExpansionListener(TreeExpansionListener tel)
    Adds a listener for TreeExpansion events.
 void addTreeSelectionListener(TreeSelectionListener tsl)
    Adds a listener for TreeSelection events.
 void addTreeWillExpandListener(TreeWillExpandListener tel)
    Adds a listener for TreeWillExpand events.
 void cancelEditing()
    Cancels the current editing session.
 void clearSelection()
    Clears the selection.
protected  void clearToggledPaths()
    Clears the cache of toggled tree paths.
 void collapsePath(TreePath path)
    Ensures that the node identified by the specified path is collapsed and viewable.
 void collapseRow(int row)
    Ensures that the node in the specified row is collapsed.
 String convertValueToText(Object value, boolean selected, boolean expanded, boolean leaf, int row, boolean hasFocus)
    Called by the renderers to convert the specified value to text.
protected static TreeModel createTreeModel(Object value)
    Returns a TreeModel wrapping the specified object.
protected  TreeModelListener createTreeModelListener()
    Creates and returns an instance of TreeModelHandler.
 void expandPath(TreePath path)
    Ensures that the node identified by the specified path is expanded and viewable.
 void expandRow(int row)
    Ensures that the node in the specified row is expanded and viewable.
 void fireTreeCollapsed(TreePath path)
    Notifies all listeners that have registered interest for notification on this event type.
 void fireTreeExpanded(TreePath path)
    Notifies all listeners that have registered interest for notification on this event type.
 void fireTreeWillCollapse(TreePath path)
    Notifies all listeners that have registered interest for notification on this event type.
 void fireTreeWillExpand(TreePath path)
    Notifies all listeners that have registered interest for notification on this event type.
protected  void fireValueChanged(TreeSelectionEvent e)
    Notifies all listeners that have registered interest for notification on this event type.
 AccessibleContext getAccessibleContext()
    Gets the AccessibleContext associated with this JTree.
 TreePath getAnchorSelectionPath()
    Returns the path identified as the anchor.
 TreeCellEditor getCellEditor()
    Returns the editor used to edit entries in the tree.
 TreeCellRenderer getCellRenderer()
    Returns the current TreeCellRenderer that is rendering each cell.
 TreePath getClosestPathForLocation(int x, int y)
    Returns the path to the node that is closest to x,y.
 int getClosestRowForLocation(int x, int y)
    Returns the row to the node that is closest to x,y.
protected static TreeModel getDefaultTreeModel()
    Creates and returns a sample TreeModel.
protected  Enumeration getDescendantToggledPaths(TreePath parent)
    Returns an Enumeration of TreePaths that have been expanded that are descendants of parent.
 boolean getDragEnabled()
    Gets the value of the dragEnabled property.
 TreePath getEditingPath()
    Returns the path to the element that is currently being edited.
 Enumeration getExpandedDescendants(TreePath parent)
    Returns an Enumeration of the descendants of the path parent that are currently expanded.
 boolean getExpandsSelectedPaths()
    Returns the expandsSelectedPaths property.
 boolean getInvokesStopCellEditing()
    Returns the indicator that tells what happens when editing is interrupted.
 Object getLastSelectedPathComponent()
    Returns the last path component in the first node of the current selection.
 TreePath getLeadSelectionPath()
    Returns the path identified as the lead.
 int getLeadSelectionRow()
    Returns the row index corresponding to the lead path.
 int getMaxSelectionRow()
    Returns the last selected row.
 int getMinSelectionRow()
    Gets the first selected row.
 TreeModel getModel()
    Returns the TreeModel that is providing the data.
 TreePath getNextMatch(String prefix, int startingRow, Position.Bias bias)
    Returns the TreePath to the next tree element that begins with a prefix.
protected  TreePath[] getPathBetweenRows(int index0, int index1)
    Returns JTreePath instances representing the path between index0 and index1 (including index1).
 Rectangle getPathBounds(TreePath path)
    Returns the Rectangle that the specified node will be drawn into.
 TreePath getPathForLocation(int x, int y)
    Returns the path for the node at the specified location.
 TreePath getPathForRow(int row)
    Returns the path for the specified row.
 Dimension getPreferredScrollableViewportSize()
    Returns the preferred display size of a JTree.
 Rectangle getRowBounds(int row)
    Returns the Rectangle that the node at the specified row is drawn in.
 int getRowCount()
    Returns the number of rows that are currently being displayed.
 int getRowForLocation(int x, int y)
    Returns the row for the specified location.
 int getRowForPath(TreePath path)
    Returns the row that displays the node identified by the specified path.
 int getRowHeight()
    Returns the height of each row.
 int getScrollableBlockIncrement(Rectangle visibleRect, int orientation, int direction)
    Returns the amount for a block increment, which is the height or width of visibleRect, based on orientation.
 boolean getScrollableTracksViewportHeight()
    Returns false to indicate that the height of the viewport does not determine the height of the table, unless the preferred height of the tree is smaller than the viewports height.
 boolean getScrollableTracksViewportWidth()
    Returns false to indicate that the width of the viewport does not determine the width of the table, unless the preferred width of the tree is smaller than the viewports width.
 int getScrollableUnitIncrement(Rectangle visibleRect, int orientation, int direction)
    Returns the amount to increment when scrolling.
 boolean getScrollsOnExpand()
    Returns the value of the scrollsOnExpand property.
 int getSelectionCount()
    Returns the number of nodes selected.
 TreeSelectionModel getSelectionModel()
    Returns the model for selections.
 TreePath getSelectionPath()
    Returns the path to the first selected node.
 TreePath[] getSelectionPaths()
    Returns the paths of all selected values.
 int[] getSelectionRows()
    Returns all of the currently selected rows.
 boolean getShowsRootHandles()
    Returns the value of the showsRootHandles property.
 int getToggleClickCount()
    Returns the number of mouse clicks needed to expand or close a node.
 String getToolTipText(MouseEvent event)
    Overrides JComponent's getToolTipText method in order to allow renderer's tips to be used if it has text set.
 TreeExpansionListener[] getTreeExpansionListeners()
    Returns an array of all the TreeExpansionListeners added to this JTree with addTreeExpansionListener().
 TreeSelectionListener[] getTreeSelectionListeners()
    Returns an array of all the TreeSelectionListeners added to this JTree with addTreeSelectionListener().
 TreeWillExpandListener[] getTreeWillExpandListeners()
    Returns an array of all the TreeWillExpandListeners added to this JTree with addTreeWillExpandListener().
 TreeUI getUI()
    Returns the L&F object that renders this component.
 String getUIClassID()
    Returns the name of the L&F class that renders this component.
 int getVisibleRowCount()
    Returns the number of rows that are displayed in the display area.
 boolean hasBeenExpanded(TreePath path)
    Returns true if the node identified by the path has ever been expanded.
 boolean isCollapsed(int row)
    Returns true if the node at the specified display row is collapsed.
 boolean isCollapsed(TreePath path)
    Returns true if the value identified by path is currently collapsed, this will return false if any of the values in path are currently not being displayed.
 boolean isEditable()
    Returns true if the tree is editable.
 boolean isEditing()
    Returns true if the tree is being edited.
 boolean isExpanded(int row)
    Returns true if the node at the specified display row is currently expanded.
 boolean isExpanded(TreePath path)
    Returns true if the node identified by the path is currently expanded,
 boolean isFixedRowHeight()
    Returns true if the height of each display row is a fixed size.
 boolean isLargeModel()
    Returns true if the tree is configured for a large model.
 boolean isPathEditable(TreePath path)
    Returns isEditable.
 boolean isPathSelected(TreePath path)
    Returns true if the item identified by the path is currently selected.
 boolean isRootVisible()
    Returns true if the root node of the tree is displayed.
 boolean isRowSelected(int row)
    Returns true if the node identified by row is selected.
 boolean isSelectionEmpty()
    Returns true if the selection is currently empty.
 boolean isVisible(TreePath path)
    Returns true if the value identified by path is currently viewable, which means it is either the root or all of its parents are expanded.
 void makeVisible(TreePath path)
    Ensures that the node identified by path is currently viewable.
protected  String paramString()
    Returns a string representation of this JTree.
protected  boolean removeDescendantSelectedPaths(TreePath path, boolean includePath)
    Removes any paths in the selection that are descendants of path.
protected  void removeDescendantToggledPaths(Enumeration toRemove)
    Removes any descendants of the TreePaths in toRemove that have been expanded.
 void removeSelectionInterval(int index0, int index1)
    Removes the nodes between index0 and index1, inclusive, from the selection.
 void removeSelectionPath(TreePath path)
    Removes the node identified by the specified path from the current selection.
 void removeSelectionPaths(TreePath[] paths)
    Removes the nodes identified by the specified paths from the current selection.
 void removeSelectionRow(int row)
    Removes the row at the index row from the current selection.
 void removeSelectionRows(int[] rows)
    Removes the rows that are selected at each of the specified rows.
 void removeTreeExpansionListener(TreeExpansionListener tel)
    Removes a listener for TreeExpansion events.
 void removeTreeSelectionListener(TreeSelectionListener tsl)
    Removes a TreeSelection listener.
 void removeTreeWillExpandListener(TreeWillExpandListener tel)
    Removes a listener for TreeWillExpand events.
 void scrollPathToVisible(TreePath path)
    Makes sure all the path components in path are expanded (except for the last path component) and scrolls so that the node identified by the path is displayed.
 void scrollRowToVisible(int row)
    Scrolls the item identified by row until it is displayed.
 void setAnchorSelectionPath(TreePath newPath)
    Sets the path identified as the anchor.
 void setCellEditor(TreeCellEditor cellEditor)
    Sets the cell editor.
 void setCellRenderer(TreeCellRenderer x)
    Sets the TreeCellRenderer that will be used to draw each cell.
 void setDragEnabled(boolean b)
    Sets the dragEnabled property, which must be true to enable automatic drag handling (the first part of drag and drop) on this component.
 void setEditable(boolean flag)
    Determines whether the tree is editable.
protected  void setExpandedState(TreePath path, boolean state)
    Sets the expanded state of this JTree.
 void setExpandsSelectedPaths(boolean newValue)
    Configures the expandsSelectedPaths property.
 void setInvokesStopCellEditing(boolean newValue)
    Determines what happens when editing is interrupted by selecting another node in the tree, a change in the tree's data, or by some other means.
 void setLargeModel(boolean newValue)
    Specifies whether the UI should use a large model.
 void setLeadSelectionPath(TreePath newPath)
    Sets the path identifies as the lead.
 void setModel(TreeModel newModel)
    Sets the TreeModel that will provide the data.
 void setRootVisible(boolean rootVisible)
    Determines whether or not the root node from the TreeModel is visible.
 void setRowHeight(int rowHeight)
    Sets the height of each cell, in pixels.
 void setScrollsOnExpand(boolean newValue)
    Sets the scrollsOnExpand property, which determines whether the tree might scroll to show previously hidden children.
 void setSelectionInterval(int index0, int index1)
    Selects the nodes between index0 and index1, inclusive.
 void setSelectionModel(TreeSelectionModel selectionModel)
    Sets the tree's selection model.
 void setSelectionPath(TreePath path)
    Selects the node identified by the specified path.
 void setSelectionPaths(TreePath[] paths)
    Selects the nodes identified by the specified array of paths.
 void setSelectionRow(int row)
    Selects the node at the specified row in the display.
 void setSelectionRows(int[] rows)
    Selects the nodes corresponding to each of the specified rows in the display.
 void setShowsRootHandles(boolean newValue)
    Sets the value of the showsRootHandles property, which specifies whether the node handles should be displayed.
 void setToggleClickCount(int clickCount)
    Sets the number of mouse clicks before a node will expand or close.
 void setUI(TreeUI ui)
    Sets the L&F object that renders this component.
 void setVisibleRowCount(int newCount)
    Sets the number of rows that are to be displayed.
 void startEditingAtPath(TreePath path)
    Selects the node identified by the specified path and initiates editing.
 boolean stopEditing()
    Ends the current editing session.
 void treeDidChange()
    Sent when the tree has changed enough that we need to resize the bounds, but not enough that we need to remove the expanded node set (e.g nodes were expanded or collapsed, or nodes were inserted into the tree).
 void updateUI()
    Notification from the UIManager that the L&F has changed.
 
Methods inherited from class javax.swing.JComponent
addAncestorListener, addNotify, addPropertyChangeListener, addPropertyChangeListener, addVetoableChangeListener, computeVisibleRect, contains, createToolTip, disable, enable, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, fireVetoableChange, getActionForKeyStroke, getActionMap, getAlignmentX, getAlignmentY, getAncestorListeners, getAutoscrolls, getBorder, getBounds, getClientProperty, getComponentGraphics, getConditionForKeyStroke, getDebugGraphicsOptions, getDefaultLocale, getGraphics, getHeight, getInputMap, getInputMap, getInputVerifier, getInsets, getInsets, getListeners, getLocation, getMaximumSize, getMinimumSize, getNextFocusableComponent, getPreferredSize, getPropertyChangeListeners, getPropertyChangeListeners, getRegisteredKeyStrokes, getRootPane, getSize, getToolTipLocation, getToolTipText, getTopLevelAncestor, getTransferHandler, getVerifyInputWhenFocusTarget, getVetoableChangeListeners, getVisibleRect, getWidth, getX, getY, grabFocus, isDoubleBuffered, isLightweightComponent, isManagingFocus, isMaximumSizeSet, isMinimumSizeSet, isOpaque, isOptimizedDrawingEnabled, isPaintingTile, isPreferredSizeSet, isRequestFocusEnabled, isValidateRoot, paint, paintBorder, paintChildren, paintComponent, paintImmediately, paintImmediately, print, printAll, printBorder, printChildren, printComponent, processComponentKeyEvent, processKeyBinding, processKeyEvent, processMouseMotionEvent, putClientProperty, registerKeyboardAction, registerKeyboardAction, removeAncestorListener, removeNotify, removePropertyChangeListener, removePropertyChangeListener, removeVetoableChangeListener, repaint, repaint, requestDefaultFocus, requestFocus, requestFocus, requestFocusInWindow, requestFocusInWindow, resetKeyboardActions, reshape, revalidate, scrollRectToVisible,