-
- All Known Implementing Classes:
- DefaultTreeModel
public interface TreeModel
The model used byJTree
.JTree
and its related classes make extensive use ofTreePath
s for indentifying nodes in theTreeModel
. If aTreeModel
returns the same object, as compared byequals
, at two different indices under the same parent than the resultingTreePath
objects will be considered equal as well. Some implementations may assume that if twoTreePath
s are equal, they identify the same node. If this condition is not met, painting problems and other oddities may result. In other words, ifgetChild
for a given parent returns the same Object (as determined byequals
) problems may result, and it is recommended you avoid doing this.Similarly
JTree
and its related classes placeTreePath
s inMap
s. As such if a node is requested twice, the return values must be equal (using theequals
method) and have the samehashCode
.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
-
-
Method Summary
Methods Modifier and Type Method and Description void
addTreeModelListener(TreeModelListener l)
Adds a listener for theTreeModelEvent
posted after the tree changes.Object
getChild(Object parent, int index)
Returns the child ofparent
at indexindex
in the parent's child array.int
getChildCount(Object parent)
Returns the number of children ofparent
.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)
Returnstrue
ifnode
is a leaf.void
removeTreeModelListener(TreeModelListener l)
Removes a listener previously added withaddTreeModelListener
.void
valueForPathChanged(TreePath path, Object newValue)
Messaged when the user has altered the value for the item identified bypath
tonewValue
.
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-
-
Method Detail
-
getRoot
Object getRoot()
Returns the root of the tree. Returnsnull
only if the tree has no nodes.- Returns:
- the root of the tree
-
getChild
Object getChild(Object parent, int index)
Returns the child ofparent
at indexindex
in the parent's child array.parent
must be a node previously obtained from this data source. This should not returnnull
ifindex
is a valid index forparent
(that isindex >= 0 && index < getChildCount(parent
)).- Parameters:
parent
- a node in the tree, obtained from this data source- Returns:
- the child of
parent
at indexindex
-
getChildCount
int getChildCount(Object parent)
Returns the number of children ofparent
. 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
- a node in the tree, obtained from this data source- Returns:
- the number of children of the node
parent
-
isLeaf
boolean isLeaf(Object node)
Returnstrue
ifnode
is a leaf. It is possible for this method to returnfalse
even ifnode
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
- a node in the tree, obtained from this data source- Returns:
- true if
node
is a leaf
-
valueForPathChanged
void valueForPathChanged(TreePath path, Object newValue)
Messaged when the user has altered the value for the item identified bypath
tonewValue
. IfnewValue
signifies a truly new value the model should post atreeNodesChanged
event.- Parameters:
path
- path to the node that the user has alterednewValue
- the new value from the TreeCellEditor
-
getIndexOfChild
int getIndexOfChild(Object parent, Object child)
Returns the index of child in parent. If eitherparent
orchild
isnull
, returns -1. If eitherparent
orchild
don't belong to this tree model, returns -1.- Parameters:
parent
- a node in the tree, obtained from this data sourcechild
- the node we are interested in- Returns:
- the index of the child in the parent, or -1 if either
child
orparent
arenull
or don't belong to this tree model
-
addTreeModelListener
void addTreeModelListener(TreeModelListener l)
Adds a listener for theTreeModelEvent
posted after the tree changes.- Parameters:
l
- the listener to add- See Also:
removeTreeModelListener(javax.swing.event.TreeModelListener)
-
removeTreeModelListener
void removeTreeModelListener(TreeModelListener l)
Removes a listener previously added withaddTreeModelListener
.- Parameters:
l
- the listener to remove- See Also:
addTreeModelListener(javax.swing.event.TreeModelListener)
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