TreeModel JDK 1.6)

Description

public interface TreeModel

The model used by JTree.

JTree and its related classes make extensive use of TreePaths for indentifying nodes in the TreeModel. If a TreeModel returns the same object, as compared by equals, at two different indices under the same parent than 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.

See also: TreePath

Methods

Hide/Show inherited methods

public void addTreeModelListener (TreeModelListener l)

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

Adds a listener for the TreeModelEvent
posted after the tree changes.
Parameters:
- l - the listener to add
See Also: TreeModel.removeTreeModelListener(javax.swing.event.TreeModelListener),

public Object getChild (Object parent, int index)

Returns the child of parent at index index in the parent's child array.

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

)).
Returns: the child of parent at index index
Parameters:
- parent - a node in the tree, obtained from this data source

public int getChildCount (Object parent)

Returns the number of children of 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.
Returns: the number of children of the node parent
Parameters:
- parent - a node in the tree, obtained from this data source

public int getIndexOfChild (Object parent, Object child)

Returns the index of child in parent.

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

public Object getRoot ()

Returns the root of the tree.

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

public boolean isLeaf (Object node)

Returns true if node is a leaf.

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.
Returns: true if node is a leaf
Parameters:
- node - a node in the tree, obtained from this data source

public void removeTreeModelListener (TreeModelListener l)

Removes a listener previously added with addTreeModelListener.

Removes a listener previously added with
addTreeModelListener.
Parameters:
- l - the listener to remove
See Also: TreeModel.addTreeModelListener(javax.swing.event.TreeModelListener),

public void valueForPathChanged (TreePath path, Object newValue)

Messaged when the user has altered the value for the item identified by path to 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 - path to the node that the user has altered
- newValue - the new value from the TreeCellEditor