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- All Known Implementing Classes:
DefaultTreeModel
public interface TreeModelThe model used byJTree.JTreeand its related classes make extensive use ofTreePaths for identifying nodes in theTreeModel. If aTreeModelreturns the same object, as compared byequals, at two different indices under the same parent than the resultingTreePathobjects will be considered equal as well. Some implementations may assume that if twoTreePaths are equal, they identify the same node. If this condition is not met, painting problems and other oddities may result. In other words, ifgetChildfor a given parent returns the same Object (as determined byequals) problems may result, and it is recommended you avoid doing this.Similarly
JTreeand its related classes placeTreePaths inMaps. As such if a node is requested twice, the return values must be equal (using theequalsmethod) 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
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Method Summary
All Methods Instance Methods Abstract Methods Modifier and Type Method Description voidaddTreeModelListener(TreeModelListener l)Adds a listener for theTreeModelEventposted after the tree changes.ObjectgetChild(Object parent, int index)Returns the child ofparentat indexindexin the parent's child array.intgetChildCount(Object parent)Returns the number of children ofparent.intgetIndexOfChild(Object parent, Object child)Returns the index of child in parent.ObjectgetRoot()Returns the root of the tree.booleanisLeaf(Object node)Returnstrueifnodeis a leaf.voidremoveTreeModelListener(TreeModelListener l)Removes a listener previously added withaddTreeModelListener.voidvalueForPathChanged(TreePath path, Object newValue)Messaged when the user has altered the value for the item identified bypathtonewValue.
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Method Detail
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getRoot
Object getRoot()
Returns the root of the tree. Returnsnullonly if the tree has no nodes.- Returns:
- the root of the tree
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getChild
Object getChild(Object parent, int index)
Returns the child ofparentat indexindexin the parent's child array.parentmust be a node previously obtained from this data source. This should not returnnullifindexis a valid index forparent(that isindex >= 0 && index < getChildCount(parent)).- Parameters:
parent- a node in the tree, obtained from this data sourceindex- index of child to be returned- Returns:
- the child of
parentat indexindex
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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.parentmust 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
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isLeaf
boolean isLeaf(Object node)
Returnstrueifnodeis a leaf. It is possible for this method to returnfalseeven ifnodehas 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
nodeis a leaf
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valueForPathChanged
void valueForPathChanged(TreePath path, Object newValue)
Messaged when the user has altered the value for the item identified bypathtonewValue. IfnewValuesignifies a truly new value the model should post atreeNodesChangedevent.- Parameters:
path- path to the node that the user has alterednewValue- the new value from the TreeCellEditor
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getIndexOfChild
int getIndexOfChild(Object parent, Object child)
Returns the index of child in parent. If eitherparentorchildisnull, returns -1. If eitherparentorchilddon'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
childorparentarenullor don't belong to this tree model
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addTreeModelListener
void addTreeModelListener(TreeModelListener l)
Adds a listener for theTreeModelEventposted after the tree changes.- Parameters:
l- the listener to add- See Also:
removeTreeModelListener(javax.swing.event.TreeModelListener)
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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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