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Java™ Platform Standard Ed. 6 |
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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.
TreePath| Method Summary | |
|---|---|
void |
addTreeModelListener(TreeModelListener l)
Adds a listener for the TreeModelEvent
posted after the tree changes. |
Object |
getChild(Object parent,
int index)
Returns the child of parent at index index
in the parent's
child array. |
int |
getChildCount(Object parent)
Returns the number of children of parent. |
int |
getIndexOfChild(Object parent,
Object child)
Returns the index of child in parent. |
Object |
getRoot()
Returns the root of the tree. |
boolean |
isLeaf(Object node)
Returns true if node is a leaf. |
void |
removeTreeModelListener(TreeModelListener l)
Removes a listener previously added with addTreeModelListener. |
void |
valueForPathChanged(TreePath path,
Object newValue)
Messaged when the user has altered the value for the item identified by path to newValue. |
| Method Detail |
|---|
Object getRoot()
null
only if the tree has no nodes.
Object getChild(Object parent,
int index)
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)).
parent - a node in the tree, obtained from this data source
parent at index indexint getChildCount(Object parent)
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.
parent - a node in the tree, obtained from this data source
parentboolean isLeaf(Object node)
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.
node - a node in the tree, obtained from this data source
node is a leaf
void valueForPathChanged(TreePath path,
Object newValue)
path to newValue.
If newValue signifies a truly new value
the model should post a treeNodesChanged event.
path - path to the node that the user has alterednewValue - the new value from the TreeCellEditor
int getIndexOfChild(Object parent,
Object child)
parent
or child is null, returns -1.
If either parent or child don't
belong to this tree model, returns -1.
parent - a node in the tree, obtained from this data sourcechild - the node we are interested in
child or parent are null
or don't belong to this tree modelvoid addTreeModelListener(TreeModelListener l)
TreeModelEvent
posted after the tree changes.
l - the listener to addremoveTreeModelListener(javax.swing.event.TreeModelListener)void removeTreeModelListener(TreeModelListener l)
addTreeModelListener.
l - the listener to removeaddTreeModelListener(javax.swing.event.TreeModelListener)
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Java™ Platform Standard Ed. 6 |
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