TreeModel (Java Platform SE 7 ) (original) (raw)
- All Known Implementing Classes:
DefaultTreeModel
public interface TreeModel
The model used by JTree.JTree and its related classes make extensive use ofTreePaths for indentifying nodes in the TreeModel. If a TreeModel returns the same object, as compared byequals, 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 twoTreePaths 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 placeTreePaths in Maps. As such if a node is requested twice, the return values must be equal (using the equals 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 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 withaddTreeModelListener. void valueForPathChanged(TreePath path,Object newValue) Messaged when the user has altered the value for the item identified by path to newValue. Method Detail
* #### getRoot [Object](../../../java/lang/Object.html "class in java.lang") getRoot() Returns the root of the tree. Returns `null` only if the tree has no nodes. Returns: the root of the tree * #### getChild [Object](../../../java/lang/Object.html "class in java.lang") getChild([Object](../../../java/lang/Object.html "class in java.lang") 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`)). Parameters: `parent` \- a node in the tree, obtained from this data source Returns: the child of `parent` at index `index` * #### getChildCount int getChildCount([Object](../../../java/lang/Object.html "class in java.lang") 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. 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](../../../java/lang/Object.html "class in java.lang") 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. Parameters: `node` \- a node in the tree, obtained from this data source Returns: true if `node` is a leaf * #### valueForPathChanged void valueForPathChanged([TreePath](../../../javax/swing/tree/TreePath.html "class in javax.swing.tree") path, [Object](../../../java/lang/Object.html "class in java.lang") 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 * #### getIndexOfChild int getIndexOfChild([Object](../../../java/lang/Object.html "class in java.lang") parent, [Object](../../../java/lang/Object.html "class in java.lang") 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. Parameters: `parent` \- a node in the tree, obtained from this data source `child` \- the node we are interested in 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 * #### addTreeModelListener void addTreeModelListener([TreeModelListener](../../../javax/swing/event/TreeModelListener.html "interface in javax.swing.event") l) Adds a listener for the `TreeModelEvent` posted after the tree changes. Parameters: `l` \- the listener to add See Also: [removeTreeModelListener(javax.swing.event.TreeModelListener)](../../../javax/swing/tree/TreeModel.html#removeTreeModelListener%28javax.swing.event.TreeModelListener%29) * #### removeTreeModelListener void removeTreeModelListener([TreeModelListener](../../../javax/swing/event/TreeModelListener.html "interface in javax.swing.event") l) Removes a listener previously added with`addTreeModelListener`. Parameters: `l` \- the listener to remove See Also: [addTreeModelListener(javax.swing.event.TreeModelListener)](../../../javax/swing/tree/TreeModel.html#addTreeModelListener%28javax.swing.event.TreeModelListener%29)
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