VariableHeightLayoutCache (Java Platform SE 8 )
Keywords: javax.swing.tree.VariableHeightLayoutCache class
Date: 2026-04-22

javax.swing.tree

## Class VariableHeightLayoutCache

- java.lang.Object
- - javax.swing.tree.AbstractLayoutCache
  - - javax.swing.tree.VariableHeightLayoutCache

- All Implemented Interfaces:
    RowMapper

      public class VariableHeightLayoutCache
      extends AbstractLayoutCache

  NOTE: This will become more open in a future release.

  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 JavaBeans™ has been added to the `java.beans` package. Please see `XMLEncoder`.

- - ### Nested Class Summary

    - ### Nested classes/interfaces inherited from class javax.swing.tree.AbstractLayoutCache

      `AbstractLayoutCache.NodeDimensions`

  - ### Field Summary

    - ### Fields inherited from class javax.swing.tree.AbstractLayoutCache

      `nodeDimensions, rootVisible, rowHeight, treeModel, treeSelectionModel`

  - ### Constructor Summary

    Constructors
    Constructor and Description
    `VariableHeightLayoutCache()`

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `Rectangle` | `getBounds(TreePath path, Rectangle placeIn)` Returns the `Rectangle` enclosing the label portion into which the item identified by `path` will be drawn.
    `boolean` | `getExpandedState(TreePath path)` Returns true if the path is expanded, and visible.
    `TreePath` | `getPathClosestTo(int x, int y)` Returns the path to the node that is closest to x,y.
    `TreePath` | `getPathForRow(int row)` Returns the path for `row`.
    `int` | `getPreferredHeight()` Returns the preferred height.
    `int` | `getPreferredWidth(Rectangle bounds)` Returns the preferred width and height for the region in `visibleRegion`.
    `int` | `getRowCount()` Returns the number of visible rows.
    `int` | `getRowForPath(TreePath path)` Returns the row where the last item identified in path is visible.
    `int` | `getVisibleChildCount(TreePath path)` Returns the number of visible children for `path`.
    `Enumeration<TreePath>` | `getVisiblePathsFrom(TreePath path)` Returns an `Enumerator` that increments over the visible paths starting at the passed in location.
    `void` | `invalidatePathBounds(TreePath path)` Instructs the `LayoutCache` that the bounds for `path` are invalid, and need to be updated.
    `void` | `invalidateSizes()` Informs the `TreeState` that it needs to recalculate all the sizes it is referencing.
    `boolean` | `isExpanded(TreePath path)` Returns true if the value identified by `path` is currently expanded.
    `void` | `setExpandedState(TreePath path, boolean isExpanded)` Marks the path `path` expanded state to `isExpanded`.
    `void` | `setModel(TreeModel newModel)` Sets the `TreeModel` that will provide the data.
    `void` | `setNodeDimensions(AbstractLayoutCache.NodeDimensions nd)` Sets the renderer that is responsible for drawing nodes in the tree.
    `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.
    `void` | `treeNodesChanged(TreeModelEvent e)` Invoked after a node (or a set of siblings) has changed in some way.
    `void` | `treeNodesInserted(TreeModelEvent e)` Invoked after nodes have been inserted into the tree.
    `void` | `treeNodesRemoved(TreeModelEvent e)` Invoked after nodes have been removed from the tree.
    `void` | `treeStructureChanged(TreeModelEvent e)` Invoked after the tree has drastically changed structure from a given node down.

    - ### Methods inherited from class javax.swing.tree.AbstractLayoutCache

      `getModel, getNodeDimensions, getNodeDimensions, getRowHeight, getRowsForPaths, getSelectionModel, isFixedRowHeight, isRootVisible, setSelectionModel`

    - ### Methods inherited from class java.lang.Object

      `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

- - ### Constructor Detail

    - #### VariableHeightLayoutCache

          public VariableHeightLayoutCache()

  - ### Method Detail

    - #### setModel

          public void setModel(TreeModel newModel)

      Sets the `TreeModel` that will provide the data.
      Overrides:
        `setModel` in class `AbstractLayoutCache`
      Parameters:
        `newModel` - the `TreeModel` that is to provide the data

    - #### setRootVisible

          public void setRootVisible(boolean rootVisible)

      Determines whether or not the root node from the `TreeModel` is visible.
      Overrides:
        `setRootVisible` in class `AbstractLayoutCache`
      Parameters:
        `rootVisible` - true if the root node of the tree is to be displayed
      See Also:
        `AbstractLayoutCache.rootVisible`

    - #### setRowHeight

          public void setRowHeight(int rowHeight)

      Sets the height of each cell. If the specified value is less than or equal to zero the current cell renderer is queried for each row's height.
      Overrides:
        `setRowHeight` in class `AbstractLayoutCache`
      Parameters:
        `rowHeight` - the height of each cell, in pixels

    - #### setNodeDimensions

          public void setNodeDimensions(AbstractLayoutCache.NodeDimensions nd)

      Sets the renderer that is responsible for drawing nodes in the tree.
      Overrides:
        `setNodeDimensions` in class `AbstractLayoutCache`
      Parameters:
        `nd` - the renderer

    - #### setExpandedState

          public void setExpandedState(TreePath path,
                                       boolean isExpanded)

      Marks the path `path` expanded state to `isExpanded`.
      Specified by:
        `setExpandedState` in class `AbstractLayoutCache`
      Parameters:
        `path` - the `TreePath` of interest
        `isExpanded` - true if the path should be expanded, otherwise false

    - #### getExpandedState

          public boolean getExpandedState(TreePath path)

      Returns true if the path is expanded, and visible.
      Specified by:
        `getExpandedState` in class `AbstractLayoutCache`
      Parameters:
        `path` - the path being queried
      Returns:
        true if the path is expanded and visible, otherwise false

    - #### getBounds

          public Rectangle getBounds(TreePath path,
                                     Rectangle placeIn)

      Returns the `Rectangle` enclosing the label portion into which the item identified by `path` will be drawn.
      Specified by:
        `getBounds` in class `AbstractLayoutCache`
      Parameters:
        `path` - the path to be drawn
        `placeIn` - the bounds of the enclosing rectangle
      Returns:
        the bounds of the enclosing rectangle or `null` if the node could not be ascertained

    - #### getPathForRow

          public TreePath getPathForRow(int row)

      Returns the path for `row`. If `row` is not visible, `null` is returned.
      Specified by:
        `getPathForRow` in class `AbstractLayoutCache`
      Parameters:
        `row` - the location of interest
      Returns:
        the path for `row`, or `null` if `row` is not visible

    - #### getRowForPath

          public int getRowForPath(TreePath path)

      Returns the row where the last item identified in path is visible. Will return -1 if any of the elements in path are not currently visible.
      Specified by:
        `getRowForPath` in class `AbstractLayoutCache`
      Parameters:
        `path` - the `TreePath` of interest
      Returns:
        the row where the last item in path is visible

    - #### getRowCount

          public int getRowCount()

      Returns the number of visible rows.
      Specified by:
        `getRowCount` in class `AbstractLayoutCache`
      Returns:
        the number of visible rows

    - #### invalidatePathBounds

          public void invalidatePathBounds(TreePath path)

      Instructs the `LayoutCache` that the bounds for `path` are invalid, and need to be updated.
      Specified by:
        `invalidatePathBounds` in class `AbstractLayoutCache`
      Parameters:
        `path` - the `TreePath` which is now invalid

    - #### getPreferredHeight

          public int getPreferredHeight()

      Returns the preferred height.
      Overrides:
        `getPreferredHeight` in class `AbstractLayoutCache`
      Returns:
        the preferred height

    - #### getPreferredWidth

          public int getPreferredWidth(Rectangle bounds)

      Returns the preferred width and height for the region in `visibleRegion`.
      Overrides:
        `getPreferredWidth` in class `AbstractLayoutCache`
      Parameters:
        `bounds` - the region being queried
      Returns:
        the preferred width for the passed in region

    - #### getPathClosestTo

          public TreePath getPathClosestTo(int x,
                                           int y)

      Returns the path to the node that is closest to x,y. If there is nothing currently visible this will return `null`, otherwise it will always return a valid path. If you need to test if the returned object is exactly at x, y you should get the bounds for the returned path and test x, y against that.
      Specified by:
        `getPathClosestTo` in class `AbstractLayoutCache`
      Parameters:
        `x` - the x-coordinate
        `y` - the y-coordinate
      Returns:
        the path to the node that is closest to x, y

    - #### getVisiblePathsFrom

          public Enumeration<TreePath> getVisiblePathsFrom(TreePath path)

      Returns an `Enumerator` that increments over the visible paths starting at the passed in location. The ordering of the enumeration is based on how the paths are displayed.
      Specified by:
        `getVisiblePathsFrom` in class `AbstractLayoutCache`
      Parameters:
        `path` - the location in the `TreePath` to start
      Returns:
        an `Enumerator` that increments over the visible paths

    - #### getVisibleChildCount

          public int getVisibleChildCount(TreePath path)

      Returns the number of visible children for `path`.
      Specified by:
        `getVisibleChildCount` in class `AbstractLayoutCache`
      Parameters:
        `path` - the path being queried
      Returns:
        the number of visible children for `path`

    - #### invalidateSizes

          public void invalidateSizes()

      Informs the `TreeState` that it needs to recalculate all the sizes it is referencing.
      Specified by:
        `invalidateSizes` in class `AbstractLayoutCache`

    - #### isExpanded

          public boolean isExpanded(TreePath path)

      Returns true if the value identified by `path` is currently expanded.
      Specified by:
        `isExpanded` in class `AbstractLayoutCache`
      Returns:
        true if the value identified by `path` is currently expanded

    - #### treeNodesChanged

          public void treeNodesChanged(TreeModelEvent e)

      Invoked after a node (or a set of siblings) has changed in some way. The node(s) have not changed locations in the tree or altered their children arrays, but other attributes have changed and may affect presentation. Example: the name of a file has changed, but it is in the same location in the file system.

      `e.path` returns the path the parent of the changed node(s).

      `e.childIndices` returns the index(es) of the changed node(s).

      Specified by:
        `treeNodesChanged` in class `AbstractLayoutCache`
      Parameters:
        `e` - the `TreeModelEvent` of interest

    - #### treeNodesInserted

          public void treeNodesInserted(TreeModelEvent e)

      Invoked after nodes have been inserted into the tree.

      `e.path` returns the parent of the new nodes.

      `e.childIndices` returns the indices of the new nodes in ascending order.

      Specified by:
        `treeNodesInserted` in class `AbstractLayoutCache`
      Parameters:
        `e` - the `TreeModelEvent` of interest

    - #### treeNodesRemoved

          public void treeNodesRemoved(TreeModelEvent e)

      Invoked after nodes have been removed from the tree. Note that if a subtree is removed from the tree, this method may only be invoked once for the root of the removed subtree, not once for each individual set of siblings removed.

      `e.path` returns the former parent of the deleted nodes.

      `e.childIndices` returns the indices the nodes had before they were deleted in ascending order.

      Specified by:
        `treeNodesRemoved` in class `AbstractLayoutCache`
      Parameters:
        `e` - the `TreeModelEvent` of interest

    - #### treeStructureChanged

          public void treeStructureChanged(TreeModelEvent e)

      Invoked after the tree has drastically changed structure from a given node down. If the path returned by `e.getPath` is of length one and the first element does not identify the current root node the first element should become the new root of the tree.

      `e.path` holds the path to the node.

      `e.childIndices` returns `null`.

      Specified by:
        `treeStructureChanged` in class `AbstractLayoutCache`
      Parameters:
        `e` - the `TreeModelEvent` of interest

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