DefaultMutableTreeNode
Java SE 6
| public class javax.swing.tree DefaultMutableTreeNode
|
Java SE 6 |
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 JavaBeansTM
has been added to the java.beans package.
Please see java.beans.XMLEncoder.
| version | 1.24 11/17/05 |
| See also | javax.swing.tree.MutableTreeNode |
| Fields | |
|---|---|
| final public static Enumeration | EMPTY_ENUMERATION An enumeration that is always empty. This is used when an enumeration of a leaf node's children is requested. |
| protected MutableTreeNode | parent this node's parent, or null if this node has no parent |
| protected Vector | children array of children, may be null if this node has no children |
| protected Object | userObject optional user object |
| protected boolean | allowsChildren true if the node is able to have children |
| Constructors | |||||
|---|---|---|---|---|---|
| public | DefaultMutableTreeNode() Creates a tree node that has no parent and no children, but which allows children. | ||||
| public | DefaultMutableTreeNode(Object userObject) Details
Creates a tree node with no parent, no children, but which allows
children, and initializes it with the specified user object.
| ||||
| public | DefaultMutableTreeNode(Object userObject, boolean allowsChildren) Details
Creates a tree node with no parent, no children, initialized with
the specified user object, and that allows children only if
specified.
| ||||
| Methods | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| public void | add(MutableTreeNode newChild) Details
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.
| ||||||||||||
| public Enumeration | breadthFirstEnumeration() Details
Creates and returns an enumeration that traverses the subtree rooted at
this node in breadth-first order. The first node returned by the
enumeration's nextElement() method is this node.Modifying the tree by inserting, removing, or moving a node invalidates any enumerations created before the modification.
| ||||||||||||
| public Enumeration | children() Details
Creates and returns a forward-order enumeration of this node's
children. Modifying this node's child array invalidates any child
enumerations created before the modification.
| ||||||||||||
| public Object | clone() Details
Overridden to make clone public. Returns a shallow copy of this node;
the new node has no parent or children and has a reference to the same
user object, if any.
| ||||||||||||
| public Enumeration | depthFirstEnumeration() Details
Creates and returns an enumeration that traverses the subtree rooted at
this node in depth-first order. The first node returned by the
enumeration's nextElement() method is the leftmost leaf.
This is the same as a postorder traversal.Modifying the tree by inserting, removing, or moving a node invalidates any enumerations created before the modification.
| ||||||||||||
| public void | insert(MutableTreeNode newChild, int childIndex) Details
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.
newChild must not be null and must not be an ancestor of
this node.
| ||||||||||||
| public Enumeration | pathFromAncestorEnumeration(TreeNode ancestor) Details
Creates and returns an enumeration that follows the path from
ancestor to this node. The enumeration's
nextElement() method first returns ancestor,
then the child of ancestor that is an ancestor of this
node, and so on, and finally returns this node. Creation of the
enumeration is O(m) where m is the number of nodes between this node
and ancestor, inclusive. Each nextElement()
message is O(1).Modifying the tree by inserting, removing, or moving a node invalidates any enumerations created before the modification.
| ||||||||||||
| public Enumeration | postorderEnumeration() Details
Creates and returns an enumeration that traverses the subtree rooted at
this node in postorder. The first node returned by the enumeration's
nextElement() method is the leftmost leaf. This is the
same as a depth-first traversal.Modifying the tree by inserting, removing, or moving a node invalidates any enumerations created before the modification.
| ||||||||||||
| public Enumeration | preorderEnumeration() Details
Creates and returns an enumeration that traverses the subtree rooted at
this node in preorder. The first node returned by the enumeration's
nextElement() method is this node.Modifying the tree by inserting, removing, or moving a node invalidates any enumerations created before the modification.
| ||||||||||||
| public void | remove(int childIndex) Details
Removes the child at the specified index from this node's children
and sets that node's parent to null. The child node to remove
must be a MutableTreeNode.
| ||||||||||||
| public void | remove(MutableTreeNode aChild) Details
Removes aChild from this node's child array, giving it a
null parent.
| ||||||||||||
| public void | removeAllChildren() Removes all of this node's children, setting their parents to null. If this node has no children, this method does nothing. | ||||||||||||
| public void | removeFromParent() Removes the subtree rooted at this node from the tree, giving this node a null parent. Does nothing if this node is the root of its tree. | ||||||||||||
| public String | toString() Details
Returns the result of sending toString() to this node's
user object, or null if this node has no user object.
| ||||||||||||
| Properties | |||||||
|---|---|---|---|---|---|---|---|
| public void | setAllowsChildren(boolean allows) Details
Determines whether or not this node is allowed to have children.
If allows is false, all of this node's children are
removed.
Note: By default, a node allows children.
| ||||||
| public boolean | getAllowsChildren() Details
Returns true if this node is allowed to have children.
| ||||||
| public TreeNode | getChildAfter(TreeNode aChild) Details
Returns the child in this node's child array that immediately
follows aChild, which must be a child of this node. If
aChild is the last child, returns null. This method
performs a linear search of this node's children for
aChild and is O(n) where n is the number of children; to
traverse the entire array of children, use an enumeration instead.
| ||||||
| public TreeNode | getChildAt(int index) Details
Returns the child at the specified index in this node's child array.
| ||||||
| public TreeNode | getChildBefore(TreeNode aChild) Details
Returns the child in this node's child array that immediately
precedes aChild, which must be a child of this node. If
aChild is the first child, returns null. This method
performs a linear search of this node's children for aChild
and is O(n) where n is the number of children.
| ||||||
| public int | getChildCount() Details
Returns the number of children of this node.
| ||||||
| public int | getDepth() Details
Returns the depth of the tree rooted at this node -- the longest
distance from this node to a leaf. If this node has no children,
returns 0. This operation is much more expensive than
getLevel() because it must effectively traverse the entire
tree rooted at this node.
| ||||||
| public TreeNode | getFirstChild() Details
Returns this node's first child. If this node has no children,
throws NoSuchElementException.
| ||||||
| public DefaultMutableTreeNode | getFirstLeaf() Details
Finds and returns the first leaf that is a descendant of this node --
either this node or its first child's first leaf.
Returns this node if it is a leaf.
| ||||||
| public int | getIndex(TreeNode aChild) Details
Returns the index of the specified child in this node's child array.
If the specified node is not a child of this node, returns
-1. This method performs a linear search and is O(n)
where n is the number of children.
| ||||||
| public TreeNode | getLastChild() Details
Returns this node's last child. If this node has no children,
throws NoSuchElementException.
| ||||||
| public DefaultMutableTreeNode | getLastLeaf() Details
Finds and returns the last leaf that is a descendant of this node --
either this node or its last child's last leaf.
Returns this node if it is a leaf.
| ||||||
| public boolean | isLeaf() Details
Returns true if this node has no children. To distinguish between
nodes that have no children and nodes that cannot have
children (e.g. to distinguish files from empty directories), use this
method in conjunction with getAllowsChildren
| ||||||
| public int | getLeafCount() Details
Returns the total number of leaves that are descendants of this node.
If this node is a leaf, returns 1. This method is O(n)
where n is the number of descendants of this node.
| ||||||
| public int | getLevel() Details
Returns the number of levels above this node -- the distance from
the root to this node. If this node is the root, returns 0.
| ||||||
| public DefaultMutableTreeNode | getNextLeaf() Details
Returns the leaf after this node or null if this node is the
last leaf in the tree.
In this implementation of the
That implementation makes the operation suitable for short
traversals from a known position. But to traverse all of the
leaves in the tree, you should use
| ||||||
| public DefaultMutableTreeNode | getNextNode() Details
Returns the node that follows this node in a preorder traversal of this
node's tree. Returns null if this node is the last node of the
traversal. This is an inefficient way to traverse the entire tree; use
an enumeration, instead.
| ||||||
| public DefaultMutableTreeNode | getNextSibling() Details
Returns the next sibling of this node in the parent's children array.
Returns null if this node has no parent or is the parent's last child.
This method performs a linear search that is O(n) where n is the number
of children; to traverse the entire array, use the parent's child
enumeration instead.
| ||||||
| public boolean | isNodeAncestor(TreeNode anotherNode) Details
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. (Note that a node is considered an ancestor of itself.)
If anotherNode is null, this method returns false. This
operation is at worst O(h) where h is the distance from the root to
this node.
| ||||||
| public boolean | isNodeChild(TreeNode aNode) Details
Returns true if aNode is a child of this node. If
aNode is null, this method returns false.
| ||||||
| public boolean | isNodeDescendant(DefaultMutableTreeNode anotherNode) Details
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. Note that a node is considered a
descendant of itself. If anotherNode is null, returns
false. This operation is at worst O(h) where h is the distance from the
root to anotherNode.
| ||||||
| public boolean | isNodeRelated(DefaultMutableTreeNode aNode) Details
Returns true if and only if aNode is in the same tree
as this node. Returns false if aNode is null.
| ||||||
| public boolean | isNodeSibling(TreeNode anotherNode) Details
Returns true if anotherNode is a sibling of (has the
same parent as) this node. A node is its own sibling. If
anotherNode is null, returns false.
| ||||||
| public void | setParent(MutableTreeNode newParent) Details
Sets this node's parent to newParent but does not
change the parent's child array. This method is called from
insert() and remove() to
reassign a child's parent, it should not be messaged from anywhere
else.
| ||||||
| public TreeNode | getParent() Details
Returns this node's parent or null if this node has no parent.
| ||||||
| public TreeNode[] | getPath() Details
Returns the path from the root, to get to this node. The last
element in the path is this node.
| ||||||
| protected TreeNode[] | getPathToRoot(TreeNode aNode, int depth) Details
Builds the parents of node up to and including the root node,
where the original node is the last element in the returned array.
The length of the returned array gives the node's depth in the
tree.
| ||||||
| public DefaultMutableTreeNode | getPreviousLeaf() Details
Returns the leaf before this node or null if this node is the
first leaf in the tree.
In this implementation of the
That implementation makes the operation suitable for short
traversals from a known position. But to traverse all of the
leaves in the tree, you should use
| ||||||
| public DefaultMutableTreeNode | getPreviousNode() Details
Returns the node that precedes this node in a preorder traversal of
this node's tree. Returns null if this node is the
first node of the traversal -- the root of the tree.
This is an inefficient way to
traverse the entire tree; use an enumeration, instead.
| ||||||
| public DefaultMutableTreeNode | getPreviousSibling() Details
Returns the previous sibling of this node in the parent's children
array. Returns null if this node has no parent or is the parent's
first child. This method performs a linear search that is O(n) where n
is the number of children.
| ||||||
| public boolean | isRoot() Details
Returns true if this node is the root of the tree. The root is
the only node in the tree with a null parent; every tree has exactly
one root.
| ||||||
| public TreeNode | getRoot() Details
Returns the root of the tree that contains this node. The root is
the ancestor with a null parent.
| ||||||
| public TreeNode | getSharedAncestor(DefaultMutableTreeNode aNode) Details
Returns the nearest common ancestor to this node and aNode.
Returns null, if no such ancestor exists -- if this node and
aNode are in different trees or if aNode is
null. A node is considered an ancestor of itself.
| ||||||
| public int | getSiblingCount() Details
Returns the number of siblings of this node. A node is its own sibling
(if it has no parent or no siblings, this method returns
1).
| ||||||
| public void | setUserObject(Object userObject) Details
Sets the user object for this node to userObject.
| ||||||
| public Object | getUserObject() Details
Returns this node's user object.
| ||||||
| public Object[] | getUserObjectPath() Returns the user object path, from the root, to get to this node. If some of the TreeNodes in the path have null user objects, the returned path will contain nulls. | ||||||
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