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TreeModel.javaAPI DocJava SE 5 API4914Fri Aug 26 14:58:22 BST 2005javax.swing.tree

TreeModel

public interface TreeModel
The interface that defines a suitable data model for a JTree. For further information on tree models, including an example of a custom implementation, see How to Use Trees in The Java Tutorial.

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.

see
TreePath
version
1.23 12/19/03
author
Rob Davis
author
Ray Ryan

Fields Summary
Constructors Summary
Methods Summary
public voidaddTreeModelListener(javax.swing.event.TreeModelListener l)
Adds a listener for the TreeModelEvent posted after the tree changes.

param
l the listener to add
see
#removeTreeModelListener

public java.lang.ObjectgetChild(java.lang.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)).

param
parent a node in the tree, obtained from this data source
return
the child of parent at index index

public intgetChildCount(java.lang.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.

param
parent a node in the tree, obtained from this data source
return
the number of children of the node parent

public intgetIndexOfChild(java.lang.Object parent, java.lang.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.

param
parent a note in the tree, obtained from this data source
param
child the node we are interested in
return
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 java.lang.ObjectgetRoot()
Returns the root of the tree. Returns null only if the tree has no nodes.

return
the root of the tree

public booleanisLeaf(java.lang.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.

param
node a node in the tree, obtained from this data source
return
true if node is a leaf

public voidremoveTreeModelListener(javax.swing.event.TreeModelListener l)
Removes a listener previously added with addTreeModelListener.

see
#addTreeModelListener
param
l the listener to remove

public voidvalueForPathChanged(javax.swing.tree.TreePath path, java.lang.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.

param
path path to the node that the user has altered
param
newValue the new value from the TreeCellEditor