javax.swing.tree
Class DefaultMutableTreeNode

java.lang.Object   
  javax.swing.tree.DefaultMutableTreeNode

All Implemented Interfaces:

Serializable , Cloneable , MutableTreeNode , TreeNode

Direct Known Subclasses:

JTree.DynamicUtilTreeNode

public class DefaultMutableTreeNode
extends Object   
implements Cloneable   , MutableTreeNode   , Serializable   

A DefaultMutableTreeNode is a general-purpose node in a tree data structure. For examples of using default mutable tree nodes, see How to Use Trees in The Java Tutorial.

A tree node may have at most one parent and 0 or more children. DefaultMutableTreeNode provides operations for examining and modifying a node's parent and children and also operations for examining the tree that the node is a part of. A node's tree is the set of all nodes that can be reached by starting at the node and following all the possible links to parents and children. A node with no parent is the root of its tree; a node with no children is a leaf. A tree may consist of many subtrees, each node acting as the root for its own subtree.

This class provides enumerations for efficiently traversing a tree or subtree in various orders or for following the path between two nodes. A DefaultMutableTreeNode may also hold a reference to a user object, the use of which is left to the user. Asking a DefaultMutableTreeNode for its string representation with toString() returns the string representation of its user object.

This is not a thread safe class.If you intend to use a DefaultMutableTreeNode (or a tree of TreeNodes) in more than one thread, you need to do your own synchronizing. A good convention to adopt is synchronizing on the root node of a tree.

While DefaultMutableTreeNode implements the MutableTreeNode interface and will allow you to add in any implementation of MutableTreeNode not all of the methods in DefaultMutableTreeNode will be applicable to all MutableTreeNodes implementations. Especially with some of the enumerations that are provided, using some of these methods assumes the DefaultMutableTreeNode contains only DefaultMutableNode instances. All of the TreeNode/MutableTreeNode methods will behave as defined no matter what implementations are added.

Warning: Serialized objects of this class will not be compatible with future Swing releases. The current serialization support is appropriate for short term storage or RMI between applications running the same version of Swing. As of 1.4, support for long term storage of all JavaBeans^TM has been added to the java.beans package. Please see XMLEncoder .

See Also:

MutableTreeNode , Serialized Form

Field Summary

protected boolean	allowsChildren true if the node is able to have children
protected Vector	children array of children, may be null if this node has no children
static Enumeration <TreeNode >	EMPTY_ENUMERATION An enumeration that is always empty.
protected MutableTreeNode	parent this node's parent, or null if this node has no parent
protected Object	userObject optional user object

Constructor Summary

DefaultMutableTreeNode ()
Creates a tree node that has no parent and no children, but which allows children.

DefaultMutableTreeNode (Object userObject)
Creates a tree node with no parent, no children, but which allows children, and initializes it with the specified user object.

DefaultMutableTreeNode (Object userObject, boolean allowsChildren)
Creates a tree node with no parent, no children, initialized with the specified user object, and that allows children only if specified.

Method Summary

void	add (MutableTreeNode newChild) Removes newChild from its parent and makes it a child of this node by adding it to the end of this node's child array.
Enumeration	breadthFirstEnumeration () Creates and returns an enumeration that traverses the subtree rooted at this node in breadth-first order.
Enumeration	children () Creates and returns a forward-order enumeration of this node's children.
Object	clone () Overridden to make clone public.
Enumeration	depthFirstEnumeration () Creates and returns an enumeration that traverses the subtree rooted at this node in depth-first order.
boolean	getAllowsChildren () Returns true if this node is allowed to have children.
TreeNode	getChildAfter (TreeNode aChild) Returns the child in this node's child array that immediately follows aChild, which must be a child of this node.
TreeNode	getChildAt (int index) Returns the child at the specified index in this node's child array.
TreeNode	getChildBefore (TreeNode aChild) Returns the child in this node's child array that immediately precedes aChild, which must be a child of this node.
int	getChildCount () Returns the number of children of this node.
int	getDepth () Returns the depth of the tree rooted at this node -- the longest distance from this node to a leaf.
TreeNode	getFirstChild () Returns this node's first child.
DefaultMutableTreeNode	getFirstLeaf () Finds and returns the first leaf that is a descendant of this node -- either this node or its first child's first leaf.
int	getIndex (TreeNode aChild) Returns the index of the specified child in this node's child array.
TreeNode	getLastChild () Returns this node's last child.
DefaultMutableTreeNode	getLastLeaf () Finds and returns the last leaf that is a descendant of this node -- either this node or its last child's last leaf.
int	getLeafCount () Returns the total number of leaves that are descendants of this node.
int	getLevel () Returns the number of levels above this node -- the distance from the root to this node.
DefaultMutableTreeNode	getNextLeaf () Returns the leaf after this node or null if this node is the last leaf in the tree.
DefaultMutableTreeNode	getNextNode () Returns the node that follows this node in a preorder traversal of this node's tree.
DefaultMutableTreeNode	getNextSibling () Returns the next sibling of this node in the parent's children array.
TreeNode	getParent () Returns this node's parent or null if this node has no parent.
TreeNode []	getPath () Returns the path from the root, to get to this node.
protected TreeNode []	getPathToRoot (TreeNode aNode, int depth) Builds the parents of node up to and including the root node, where the original node is the last element in the returned array.
DefaultMutableTreeNode	getPreviousLeaf () Returns the leaf before this node or null if this node is the first leaf in the tree.
DefaultMutableTreeNode	getPreviousNode () Returns the node that precedes this node in a preorder traversal of this node's tree.
DefaultMutableTreeNode	getPreviousSibling () Returns the previous sibling of this node in the parent's children array.
TreeNode	getRoot () Returns the root of the tree that contains this node.
TreeNode	getSharedAncestor (DefaultMutableTreeNode aNode) Returns the nearest common ancestor to this node and aNode.
int	getSiblingCount () Returns the number of siblings of this node.
Object	getUserObject () Returns this node's user object.
Object []	getUserObjectPath () Returns the user object path, from the root, to get to this node.
void	insert (MutableTreeNode newChild, int childIndex) Removes newChild from its present parent (if it has a parent), sets the child's parent to this node, and then adds the child to this node's child array at index childIndex.
boolean	isLeaf () Returns true if this node has no children.
boolean	isNodeAncestor (TreeNode anotherNode) Returns true if anotherNode is an ancestor of this node -- if it is this node, this node's parent, or an ancestor of this node's parent.
boolean	isNodeChild (TreeNode aNode) Returns true if aNode is a child of this node.
boolean	isNodeDescendant (DefaultMutableTreeNode anotherNode) Returns true if anotherNode is a descendant of this node -- if it is this node, one of this node's children, or a descendant of one of this node's children.
boolean	isNodeRelated (DefaultMutableTreeNode aNode) Returns true if and only if aNode is in the same tree as this node.
boolean	isNodeSibling (TreeNode anotherNode) Returns true if anotherNode is a sibling of (has the same parent as) this node.
boolean	isRoot () Returns true if this node is the root of the tree.
Enumeration	pathFromAncestorEnumeration (TreeNode ancestor) Creates and returns an enumeration that follows the path from ancestor to this node.
Enumeration	postorderEnumeration () Creates and returns an enumeration that traverses the subtree rooted at this node in postorder.
Enumeration	preorderEnumeration () Creates and returns an enumeration that traverses the subtree rooted at this node in preorder.
void	remove (int childIndex) Removes the child at the specified index from this node's children and sets that node's parent to null.
void	remove (MutableTreeNode aChild) Removes aChild from this node's child array, giving it a null parent.
void	removeAllChildren () Removes all of this node's children, setting their parents to null.
void	removeFromParent () Removes the subtree rooted at this node from the tree, giving this node a null parent.
void	setAllowsChildren (boolean allows) Determines whether or not this node is allowed to have children.
void	setParent (MutableTreeNode newParent) Sets this node's parent to newParent but does not change the parent's child array.
void	setUserObject (Object userObject) Sets the user object for this node to userObject.
String	toString () Returns the result of sending toString() to this node's user object, or null if this node has no user object.

Methods inherited from class java.lang.Object

equals , finalize , getClass , hashCode , notify , notifyAll , wait , wait , wait

Field Detail

EMPTY_ENUMERATION

public static final Enumeration   <TreeNode   > EMPTY_ENUMERATION

An enumeration that is always empty. This is used when an enumeration of a leaf node's children is requested.

parent

protected MutableTreeNode    parent

this node's parent, or null if this node has no parent

children

protected Vector    children

array of children, may be null if this node has no children

userObject

protected transient Object    userObject

optional user object

allowsChildren

protected boolean allowsChildren

true if the node is able to have children

Constructor Detail

DefaultMutableTreeNode