OpenJDK 27 · javax.swing.tree.TreeModel · APIdia, the JavaDoc alternative

The model used by JTree.

JTree and its related classes make extensive use of TreePaths for identifying nodes in the TreeModel. If a TreeModel returns the same object, as compared by equals, at two different indices under the same parent then the resulting TreePath objects will be considered equal as well. Some implementations may assume that if two TreePaths are equal, they identify the same node. If this condition is not met, painting problems and other oddities may result. In other words, if getChild for a given parent returns the same Object (as determined by equals) problems may result, and it is recommended you avoid doing this.

Similarly JTree and its related classes place TreePaths in Maps. As such if a node is requested twice, the return values must be equal (using the equals method) and have the same hashCode.

For further information on tree models, including an example of a custom implementation, see How to Use Trees in The Java Tutorial.

Method Summary

Modifier and Type	Method and Description
public void	addTreeModelListener(TreeModelListener the listener to add l) Adds a listener for the `TreeModelEvent` posted after the tree changes.
public Object	Returns: the child of `parent` at index `index` getChild(Object a node in the tree, obtained from this data source parent, int index of child to be returned index) Returns the child of `parent` at index `index` in the parent's child array.
public int	Returns: the number of children of the node `parent` getChildCount(Object a node in the tree, obtained from this data source parent) Returns the number of children of `parent`.
public int	Returns: the index of the child in the parent, or -1 if either `child` or `parent` are `null` or don't belong to this tree model getIndexOfChild(Object a node in the tree, obtained from this data source parent, Object the node we are interested in child) Returns the index of child in parent.
public Object	Returns: the root of the tree getRoot() Returns the root of the tree.
public boolean	Returns: true if `node` is a leaf isLeaf(Object a node in the tree, obtained from this data source node) Returns `true` if `node` is a leaf.
public void	removeTreeModelListener(TreeModelListener the listener to remove l) Removes a listener previously added with `addTreeModelListener`.
public void	valueForPathChanged(TreePath path to the node that the user has altered path, Object the new value from the TreeCellEditor newValue) Messaged when the user has altered the value for the item identified by `path` to `newValue`.

Method Detail

addTreeModelListener back to summary

addTreeModelListener	back to summary
public void addTreeModelListener(TreeModelListener l) Adds a listener for the `TreeModelEvent` posted after the tree changes. Parameters l:TreeModelListener the listener to add See Also `removeTreeModelListener`

public void addTreeModelListener(TreeModelListener l)

Adds a listener for the TreeModelEvent posted after the tree changes.

Parameters

l:TreeModelListener: the listener to add

See Also

removeTreeModelListener

getChild back to summary

getChild	back to summary
public Object getChild(Object parent, int index) Returns the child of `parent` at index `index` in the parent's child array. `parent` must be a node previously obtained from this data source. This should not return `null` if `index` is a valid index for `parent` (that is `index >= 0 && index < getChildCount(parent`)). Parameters parent:Object a node in the tree, obtained from this data source index:int index of child to be returned Returns:Object the child of `parent` at index `index`

public Object getChild(Object parent, int index)

Returns the child of parent at index index in the parent's child array. parent must be a node previously obtained from this data source. This should not return null if index is a valid index for parent (that is index >= 0 && index < getChildCount(parent)).

Parameters

parent:Object: a node in the tree, obtained from this data source
index:int: index of child to be returned

Returns:Object

the child of parent at index index

getChildCount back to summary

getChildCount	back to summary
public int getChildCount(Object parent) Returns the number of children of `parent`. Returns 0 if the node is a leaf or if it has no children. `parent` must be a node previously obtained from this data source. Parameters parent:Object a node in the tree, obtained from this data source Returns:int the number of children of the node `parent`

public int getChildCount(Object parent)

Returns the number of children of parent. Returns 0 if the node is a leaf or if it has no children. parent must be a node previously obtained from this data source.

Parameters

parent:Object: a node in the tree, obtained from this data source

Returns:int

the number of children of the node parent

getIndexOfChild back to summary

getIndexOfChild	back to summary
public int getIndexOfChild(Object parent, Object child) Returns the index of child in parent. If either `parent` or `child` is `null`, returns -1. If either `parent` or `child` don't belong to this tree model, returns -1. Parameters parent:Object a node in the tree, obtained from this data source child:Object the node we are interested in Returns:int the index of the child in the parent, or -1 if either `child` or `parent` are `null` or don't belong to this tree model

public int getIndexOfChild(Object parent, Object child)

Returns the index of child in parent. If either parent or child is null, returns -1. If either parent or child don't belong to this tree model, returns -1.

Parameters

parent:Object: a node in the tree, obtained from this data source
child:Object: the node we are interested in

Returns:int

the index of the child in the parent, or -1 if either child or parent are null or don't belong to this tree model

getRoot back to summary

getRoot	back to summary
public Object getRoot() Returns the root of the tree. Returns `null` only if the tree has no nodes. Returns:Object the root of the tree

public Object getRoot()

Returns the root of the tree. Returns null only if the tree has no nodes.

Returns:Object: the root of the tree

isLeaf back to summary

isLeaf	back to summary
public boolean isLeaf(Object node) Returns `true` if `node` is a leaf. It is possible for this method to return `false` even if `node` has no children. A directory in a filesystem, for example, may contain no files; the node representing the directory is not a leaf, but it also has no children. Parameters node:Object a node in the tree, obtained from this data source Returns:boolean true if `node` is a leaf

public boolean isLeaf(Object node)

Returns true if node is a leaf. It is possible for this method to return false even if node has no children. A directory in a filesystem, for example, may contain no files; the node representing the directory is not a leaf, but it also has no children.

Parameters

node:Object: a node in the tree, obtained from this data source

Returns:boolean

true if node is a leaf

removeTreeModelListener back to summary

removeTreeModelListener	back to summary
public void removeTreeModelListener(TreeModelListener l) Removes a listener previously added with `addTreeModelListener`. Parameters l:TreeModelListener the listener to remove See Also `addTreeModelListener`

public void removeTreeModelListener(TreeModelListener l)

Removes a listener previously added with addTreeModelListener.

Parameters

l:TreeModelListener: the listener to remove

See Also

addTreeModelListener

valueForPathChanged back to summary

valueForPathChanged	back to summary
public void valueForPathChanged(TreePath path, Object newValue) Messaged when the user has altered the value for the item identified by `path` to `newValue`. If `newValue` signifies a truly new value the model should post a `treeNodesChanged` event. Parameters path:TreePath path to the node that the user has altered newValue:Object the new value from the TreeCellEditor

public void valueForPathChanged(TreePath path, Object newValue)

Messaged when the user has altered the value for the item identified by path to newValue. If newValue signifies a truly new value the model should post a treeNodesChanged event.

Parameters

path:TreePath: path to the node that the user has altered
newValue:Object: the new value from the TreeCellEditor

public Interface TreeModel

Method Summary

Method Detail