TreeSelectionModel (Java SE 25 & JDK 25)
Description: declaration: module: java.desktop, package: javax.swing.tree, interface: TreeSelectionModel
Keywords: javax.swing.tree.TreeSelectionModel interface

# Interface TreeSelectionModel

All Known Implementing Classes:
  `DefaultTreeSelectionModel, JTree.EmptySelectionModel`

public interface TreeSelectionModel
This interface represents the current state of the selection for the tree component. For information and examples of using tree selection models, see How to Use Trees in The Java Tutorial.

The state of the tree selection is characterized by a set of TreePaths, and optionally a set of integers. The mapping from TreePath to integer is done by way of an instance of RowMapper. It is not necessary for a TreeSelectionModel to have a RowMapper to correctly operate, but without a RowMapper `getSelectionRows` will return null.

A TreeSelectionModel can be configured to allow only one path (`SINGLE_TREE_SELECTION`) a number of contiguous paths (`CONTIGUOUS_TREE_SELECTION`) or a number of discontiguous paths (`DISCONTIGUOUS_TREE_SELECTION`). A `RowMapper` is used to determine if TreePaths are contiguous. In the absence of a RowMapper `CONTIGUOUS_TREE_SELECTION` and `DISCONTIGUOUS_TREE_SELECTION` behave the same, that is they allow any number of paths to be contained in the TreeSelectionModel.

For a selection model of `CONTIGUOUS_TREE_SELECTION` any time the paths are changed (`setSelectionPath`, `addSelectionPath` ...) the TreePaths are again checked to make they are contiguous. A check of the TreePaths can also be forced by invoking `resetRowSelection`. How a set of discontiguous TreePaths is mapped to a contiguous set is left to implementors of this interface to enforce a particular policy.

Implementations should combine duplicate TreePaths that are added to the selection. For example, the following code

      TreePath[] paths = new TreePath[] { treePath, treePath };
      treeSelectionModel.setSelectionPaths(paths);

should result in only one path being selected: `treePath`, and not two copies of `treePath`.

The lead TreePath is the last path that was added (or set). The lead row is then the row that corresponds to the TreePath as determined from the RowMapper.

- ## Field Summary

  Fields
  Modifier and Type
  Field
  Description
  `static final int`
  `CONTIGUOUS_TREE_SELECTION`
  Selection can only be contiguous.
  `static final int`
  `DISCONTIGUOUS_TREE_SELECTION`
  Selection can contain any number of items that are not necessarily contiguous.
  `static final int`
  `SINGLE_TREE_SELECTION`
  Selection can only contain one path at a time.

- ## Method Summary

  Modifier and Type
  Method
  Description
  `void`
  `addPropertyChangeListener(PropertyChangeListener listener)`
  Adds a PropertyChangeListener to the listener list.
  `void`
  `addSelectionPath(TreePath path)`
  Adds path to the current selection.
  `void`
  `addSelectionPaths(TreePath[] paths)`
  Adds paths to the current selection.
  `void`
  `addTreeSelectionListener(TreeSelectionListener x)`
  Adds x to the list of listeners that are notified each time the set of selected TreePaths changes.
  `void`
  `clearSelection()`
  Empties the current selection.
  `TreePath`
  `getLeadSelectionPath()`
  Returns the last path that was added.
  `int`
  `getLeadSelectionRow()`
  Returns the lead selection index.
  `int`
  `getMaxSelectionRow()`
  Returns the largest value obtained from the RowMapper for the current set of selected TreePaths.
  `int`
  `getMinSelectionRow()`
  Returns the smallest value obtained from the RowMapper for the current set of selected TreePaths.
  `RowMapper`
  `getRowMapper()`
  Returns the RowMapper instance that is able to map a TreePath to a row.
  `int`
  `getSelectionCount()`
  Returns the number of paths that are selected.
  `int`
  `getSelectionMode()`
  Returns the current selection mode, one of `SINGLE_TREE_SELECTION`, `CONTIGUOUS_TREE_SELECTION` or `DISCONTIGUOUS_TREE_SELECTION`.
  `TreePath`
  `getSelectionPath()`
  Returns the first path in the selection.
  `TreePath[]`
  `getSelectionPaths()`
  Returns the paths in the selection.
  `int[]`
  `getSelectionRows()`
  Returns all of the currently selected rows.
  `boolean`
  `isPathSelected(TreePath path)`
  Returns true if the path, `path`, is in the current selection.
  `boolean`
  `isRowSelected(int row)`
  Returns true if the row identified by `row` is selected.
  `boolean`
  `isSelectionEmpty()`
  Returns true if the selection is currently empty.
  `void`
  `removePropertyChangeListener(PropertyChangeListener listener)`
  Removes a PropertyChangeListener from the listener list.
  `void`
  `removeSelectionPath(TreePath path)`
  Removes path from the selection.
  `void`
  `removeSelectionPaths(TreePath[] paths)`
  Removes paths from the selection.
  `void`
  `removeTreeSelectionListener(TreeSelectionListener x)`
  Removes x from the list of listeners that are notified each time the set of selected TreePaths changes.
  `void`
  `resetRowSelection()`
  Updates this object's mapping from TreePaths to rows.
  `void`
  `setRowMapper(RowMapper newMapper)`
  Sets the RowMapper instance.
  `void`
  `setSelectionMode(int mode)`
  Sets the selection model, which must be one of SINGLE_TREE_SELECTION, CONTIGUOUS_TREE_SELECTION or DISCONTIGUOUS_TREE_SELECTION.
  `void`
  `setSelectionPath(TreePath path)`
  Sets the selection to path.
  `void`
  `setSelectionPaths(TreePath[] paths)`
  Sets the selection to path.

- ## Field Details

  - ### SINGLE_TREE_SELECTION

    static final int SINGLE_TREE_SELECTION
    Selection can only contain one path at a time.
    See Also:
      - Constant Field Values

  - ### CONTIGUOUS_TREE_SELECTION

    static final int CONTIGUOUS_TREE_SELECTION
    Selection can only be contiguous. This will only be enforced if a RowMapper instance is provided. That is, if no RowMapper is set this behaves the same as DISCONTIGUOUS_TREE_SELECTION.
    See Also:
      - Constant Field Values

  - ### DISCONTIGUOUS_TREE_SELECTION

    static final int DISCONTIGUOUS_TREE_SELECTION
    Selection can contain any number of items that are not necessarily contiguous.
    See Also:
      - Constant Field Values

- ## Method Details

  - ### setSelectionMode

    void setSelectionMode(int mode)
    Sets the selection model, which must be one of SINGLE_TREE_SELECTION, CONTIGUOUS_TREE_SELECTION or DISCONTIGUOUS_TREE_SELECTION.

    This may change the selection if the current selection is not valid for the new mode. For example, if three TreePaths are selected when the mode is changed to `SINGLE_TREE_SELECTION`, only one TreePath will remain selected. It is up to the particular implementation to decide what TreePath remains selected.

    Parameters:
      `mode` - selection mode to be set

  - ### getSelectionMode

    int getSelectionMode()
    Returns the current selection mode, one of `SINGLE_TREE_SELECTION`, `CONTIGUOUS_TREE_SELECTION` or `DISCONTIGUOUS_TREE_SELECTION`.
    Returns:
      the current selection mode

  - ### setSelectionPath

    void setSelectionPath(TreePath path)
    Sets the selection to path. If this represents a change, then the TreeSelectionListeners are notified. If `path` is null, this has the same effect as invoking `clearSelection`.
    Parameters:
      `path` - new path to select

  - ### setSelectionPaths

    void setSelectionPaths(TreePath[] paths)
    Sets the selection to path. If this represents a change, then the TreeSelectionListeners are notified. If `paths` is null, this has the same effect as invoking `clearSelection`.
    Parameters:
      `paths` - new selection

  - ### addSelectionPath

    void addSelectionPath(TreePath path)
    Adds path to the current selection. If path is not currently in the selection the TreeSelectionListeners are notified. This has no effect if `path` is null.
    Parameters:
      `path` - the new path to add to the current selection

  - ### addSelectionPaths

    void addSelectionPaths(TreePath[] paths)
    Adds paths to the current selection. If any of the paths in paths are not currently in the selection the TreeSelectionListeners are notified. This has no effect if `paths` is null.
    Parameters:
      `paths` - the new paths to add to the current selection

  - ### removeSelectionPath

    void removeSelectionPath(TreePath path)
    Removes path from the selection. If path is in the selection The TreeSelectionListeners are notified. This has no effect if `path` is null.
    Parameters:
      `path` - the path to remove from the selection

  - ### removeSelectionPaths

    void removeSelectionPaths(TreePath[] paths)
    Removes paths from the selection. If any of the paths in `paths` are in the selection, the TreeSelectionListeners are notified. This method has no effect if `paths` is null.
    Parameters:
      `paths` - the path to remove from the selection

  - ### getSelectionPath

    TreePath getSelectionPath()
    Returns the first path in the selection. How first is defined is up to implementors, and may not necessarily be the TreePath with the smallest integer value as determined from the `RowMapper`.
    Returns:
      the first path in the selection

  - ### getSelectionPaths

    TreePath[] getSelectionPaths()
    Returns the paths in the selection. This will return null (or an empty array) if nothing is currently selected.
    Returns:
      the paths in the selection

  - ### getSelectionCount

    int getSelectionCount()
    Returns the number of paths that are selected.
    Returns:
      the number of paths that are selected

  - ### isPathSelected

    boolean isPathSelected(TreePath path)
    Returns true if the path, `path`, is in the current selection.
    Parameters:
      `path` - the path to be looked for
    Returns:
      whether the `path` is in the current selection

  - ### isSelectionEmpty

    boolean isSelectionEmpty()
    Returns true if the selection is currently empty.
    Returns:
      whether the selection is currently empty

  - ### clearSelection

    void clearSelection()
    Empties the current selection. If this represents a change in the current selection, the selection listeners are notified.

  - ### setRowMapper

    void setRowMapper(RowMapper newMapper)
    Sets the RowMapper instance. This instance is used to determine the row for a particular TreePath.
    Parameters:
      `newMapper` - RowMapper to be set

  - ### getRowMapper

    RowMapper getRowMapper()
    Returns the RowMapper instance that is able to map a TreePath to a row.
    Returns:
      the RowMapper instance that is able to map a TreePath to a row

  - ### getSelectionRows

    int[] getSelectionRows()
    Returns all of the currently selected rows. This will return null (or an empty array) if there are no selected TreePaths or a RowMapper has not been set.
    Returns:
      all of the currently selected rows

  - ### getMinSelectionRow

    int getMinSelectionRow()
    Returns the smallest value obtained from the RowMapper for the current set of selected TreePaths. If nothing is selected, or there is no RowMapper, this will return -1.
    Returns:
      the smallest value obtained from the RowMapper for the current set of selected TreePaths

  - ### getMaxSelectionRow

    int getMaxSelectionRow()
    Returns the largest value obtained from the RowMapper for the current set of selected TreePaths. If nothing is selected, or there is no RowMapper, this will return -1.
    Returns:
      the largest value obtained from the RowMapper for the current set of selected TreePaths

  - ### isRowSelected

    boolean isRowSelected(int row)
    Returns true if the row identified by `row` is selected.
    Parameters:
      `row` - row to check
    Returns:
      whether the row is selected

  - ### resetRowSelection

    void resetRowSelection()
    Updates this object's mapping from TreePaths to rows. This should be invoked when the mapping from TreePaths to integers has changed (for example, a node has been expanded).

    You do not normally have to call this; JTree and its associated listeners will invoke this for you. If you are implementing your own view class, then you will have to invoke this.

  - ### getLeadSelectionRow

    int getLeadSelectionRow()
    Returns the lead selection index. That is the last index that was added.
    Returns:
      the lead selection index

  - ### getLeadSelectionPath

    TreePath getLeadSelectionPath()
    Returns the last path that was added. This may differ from the leadSelectionPath property maintained by the JTree.
    Returns:
      the last path that was added

  - ### addPropertyChangeListener

    void addPropertyChangeListener(PropertyChangeListener listener)
    Adds a PropertyChangeListener to the listener list. The listener is registered for all properties.

    A PropertyChangeEvent will get fired when the selection mode changes.

    Parameters:
      `listener` - the PropertyChangeListener to be added

  - ### removePropertyChangeListener

    void removePropertyChangeListener(PropertyChangeListener listener)
    Removes a PropertyChangeListener from the listener list. This removes a PropertyChangeListener that was registered for all properties.
    Parameters:
      `listener` - the PropertyChangeListener to be removed

  - ### addTreeSelectionListener

    void addTreeSelectionListener(TreeSelectionListener x)
    Adds x to the list of listeners that are notified each time the set of selected TreePaths changes.
    Parameters:
      `x` - the new listener to be added

  - ### removeTreeSelectionListener

    void removeTreeSelectionListener(TreeSelectionListener x)
    Removes x from the list of listeners that are notified each time the set of selected TreePaths changes.
    Parameters:
      `x` - the listener to remove