Java™ Platform
Standard Ed. 6

javax.swing.tree
Class DefaultTreeModel

java.lang.Object
  extended by javax.swing.tree.DefaultTreeModel
All Implemented Interfaces:
Serializable, TreeModel

public class DefaultTreeModel
extends Object
implements Serializable, TreeModel

A simple tree data model that uses TreeNodes. For further information and examples that use DefaultTreeModel, see How to Use Trees in The Java Tutorial.

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 XMLEncoder.


Field Summary
protected  boolean asksAllowsChildren
          Determines how the isLeaf method figures out if a node is a leaf node.
protected  EventListenerList listenerList
          Listeners.
protected  TreeNode root
          Root of the tree.
 
Constructor Summary
DefaultTreeModel(TreeNode root)
          Creates a tree in which any node can have children.
DefaultTreeModel(TreeNode root, boolean asksAllowsChildren)
          Creates a tree specifying whether any node can have children, or whether only certain nodes can have children.
 
Method Summary
 void addTreeModelListener(TreeModelListener l)
          Adds a listener for the TreeModelEvent posted after the tree changes.
 boolean asksAllowsChildren()
          Tells how leaf nodes are determined.
protected  void fireTreeNodesChanged(Object source, Object[] path, int[] childIndices, Object[] children)
          Notifies all listeners that have registered interest for notification on this event type.
protected  void fireTreeNodesInserted(Object source, Object[] path, int[] childIndices, Object[] children)
          Notifies all listeners that have registered interest for notification on this event type.
protected  void fireTreeNodesRemoved(Object source, Object[] path, int[] childIndices, Object[] children)
          Notifies all listeners that have registered interest for notification on this event type.
protected  void fireTreeStructureChanged(Object source, Object[] path, int[] childIndices, Object[] children)
          Notifies all listeners that have registered interest for notification on this event type.
 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.
<T extends EventListener>
T[]
getListeners(Class<T> listenerType)
          Returns an array of all the objects currently registered as FooListeners upon this model.
 TreeNode[] getPathToRoot(TreeNode aNode)
          Builds the parents of node up to and including the root node, where the original node is the last element in the returned array.
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.
 Object getRoot()
          Returns the root of the tree.
 TreeModelListener[] getTreeModelListeners()
          Returns an array of all the tree model listeners registered on this model.
 void insertNodeInto(MutableTreeNode newChild, MutableTreeNode parent, int index)
          Invoked this to insert newChild at location index in parents children.
 boolean isLeaf(Object node)
          Returns whether the specified node is a leaf node.
 void nodeChanged(TreeNode node)
          Invoke this method after you've changed how node is to be represented in the tree.
 void nodesChanged(TreeNode node, int[] childIndices)
          Invoke this method after you've changed how the children identified by childIndicies are to be represented in the tree.
 void nodeStructureChanged(TreeNode node)
          Invoke this method if you've totally changed the children of node and its childrens children...
 void nodesWereInserted(TreeNode node, int[] childIndices)
          Invoke this method after you've inserted some TreeNodes into node.
 void nodesWereRemoved(TreeNode node, int[] childIndices, Object[] removedChildren)
          Invoke this method after you've removed some TreeNodes from node.
 void reload()
          Invoke this method if you've modified the TreeNodes upon which this model depends.
 void reload(TreeNode node)
          Invoke this method if you've modified the TreeNodes upon which this model depends.
 void removeNodeFromParent(MutableTreeNode node)
          Message this to remove node from its parent.
 void removeTreeModelListener(TreeModelListener l)
          Removes a listener previously added with addTreeModelListener().
 void setAsksAllowsChildren(boolean newValue)
          Sets whether or not to test leafness by asking getAllowsChildren() or isLeaf() to the TreeNodes.
 void setRoot(TreeNode root)
          Sets the root to root.
 void valueForPathChanged(TreePath path, Object newValue)
          This sets the user object of the TreeNode identified by path and posts a node changed.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

root

protected TreeNode root
Root of the tree.


listenerList

protected EventListenerList listenerList
Listeners.


asksAllowsChildren

protected boolean asksAllowsChildren
Determines how the isLeaf method figures out if a node is a leaf node. If true, a node is a leaf node if it does not allow children. (If it allows children, it is not a leaf node, even if no children are present.) That lets you distinguish between folder nodes and file nodes in a file system, for example.

If this value is false, then any node which has no children is a leaf node, and any node may acquire children.

See Also:
TreeNode.getAllowsChildren(), TreeModel.isLeaf(java.lang.Object), setAsksAllowsChildren(boolean)
Constructor Detail

DefaultTreeModel

public DefaultTreeModel(TreeNode root)
Creates a tree in which any node can have children.

Parameters:
root - a TreeNode object that is the root of the tree
See Also:
DefaultTreeModel(TreeNode, boolean)

DefaultTreeModel

public DefaultTreeModel(TreeNode root,
                        boolean asksAllowsChildren)
Creates a tree specifying whether any node can have children, or whether only certain nodes can have children.

Parameters:
root - a TreeNode object that is the root of the tree
asksAllowsChildren - a boolean, false if any node can have children, true if each node is asked to see if it can have children
See Also:
asksAllowsChildren
Method Detail

setAsksAllowsChildren

public void setAsksAllowsChildren(boolean newValue)
Sets whether or not to test leafness by asking getAllowsChildren() or isLeaf() to the TreeNodes. If newvalue is true, getAllowsChildren() is messaged, otherwise isLeaf() is messaged.


asksAllowsChildren

public boolean asksAllowsChildren()
Tells how leaf nodes are determined.

Returns:
true if only nodes which do not allow children are leaf nodes, false if nodes which have no children (even if allowed) are leaf nodes
See Also:
asksAllowsChildren

setRoot

public void setRoot(TreeNode root)
Sets the root to root. A null root implies the tree is to display nothing, and is legal.


getRoot

public Object getRoot()
Returns the root of the tree. Returns null only if the tree has no nodes.

Specified by:
getRoot in interface TreeModel
Returns:
the root of the tree

getIndexOfChild

public int getIndexOfChild(Object parent,
                           Object child)
Returns the index of child in parent. If either the parent or child is null, returns -1.

Specified by:
getIndexOfChild in interface TreeModel
Parameters:
parent - a note 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 the parent or the child is null

getChild

public Object getChild(Object 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)).

Specified by:
getChild in interface TreeModel
Parameters:
parent - a node in the tree, obtained from this data source
Returns:
the child of parent at index index

getChildCount

public int getChildCount(Object 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.

Specified by:
getChildCount in interface TreeModel
Parameters:
parent - a node in the tree, obtained from this data source
Returns:
the number of children of the node parent

isLeaf

public boolean isLeaf(Object node)
Returns whether the specified node is a leaf node. The way the test is performed depends on the askAllowsChildren setting.

Specified by:
isLeaf in interface TreeModel
Parameters:
node - the node to check
Returns:
true if the node is a leaf node
See Also:
asksAllowsChildren, TreeModel.isLeaf(java.lang.Object)

reload

public void reload()
Invoke this method if you've modified the TreeNodes upon which this model depends. The model will notify all of its listeners that the model has changed.


valueForPathChanged

public void valueForPathChanged(TreePath path,
                                Object newValue)
This sets the user object of the TreeNode identified by path and posts a node changed. If you use custom user objects in the TreeModel you're going to need to subclass this and set the user object of the changed node to something meaningful.

Specified by:
valueForPathChanged in interface TreeModel
Parameters:
path - path to the node that the user has altered
newValue - the new value from the TreeCellEditor

insertNodeInto

public void insertNodeInto(MutableTreeNode newChild,
                           MutableTreeNode parent,
                           int index)
Invoked this to insert newChild at location index in parents children. This will then message nodesWereInserted to create the appropriate event. This is the preferred way to add children as it will create the appropriate event.


removeNodeFromParent

public void removeNodeFromParent(MutableTreeNode node)
Message this to remove node from its parent. This will message nodesWereRemoved to create the appropriate event. This is the preferred way to remove a node as it handles the event creation for you.


nodeChanged

public void nodeChanged(TreeNode node)
Invoke this method after you've changed how node is to be represented in the tree.


reload

public void reload(TreeNode node)
Invoke this method if you've modified the TreeNodes upon which this model depends. The model will notify all of its listeners that the model has changed below the given node.

Parameters:
node - the node below which the model has changed

nodesWereInserted

public void nodesWereInserted(TreeNode node,
                              int[] childIndices)
Invoke this method after you've inserted some TreeNodes into node. childIndices should be the index of the new elements and must be sorted in ascending order.


nodesWereRemoved

public void nodesWereRemoved(TreeNode node,
                             int[] childIndices,
                             Object[] removedChildren)
Invoke this method after you've removed some TreeNodes from node. childIndices should be the index of the removed elements and must be sorted in ascending order. And removedChildren should be the array of the children objects that were removed.


nodesChanged

public void nodesChanged(TreeNode node,
                         int[] childIndices)
Invoke this method after you've changed how the children identified by childIndicies are to be represented in the tree.


nodeStructureChanged

public void nodeStructureChanged(TreeNode node)
Invoke this method if you've totally changed the children of node and its childrens children... This will post a treeStructureChanged event.


getPathToRoot

public TreeNode[] getPathToRoot(TreeNode aNode)
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.

Parameters:
aNode - the TreeNode to get the path for

getPathToRoot

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. The length of the returned array gives the node's depth in the tree.

Parameters:
aNode - the TreeNode to get the path for
depth - an int giving the number of steps already taken towards the root (on recursive calls), used to size the returned array
Returns:
an array of TreeNodes giving the path from the root to the specified node

addTreeModelListener

public void addTreeModelListener(TreeModelListener l)
Adds a listener for the TreeModelEvent posted after the tree changes.

Specified by:
addTreeModelListener in interface TreeModel
Parameters:
l - the listener to add
See Also:
removeTreeModelListener(javax.swing.event.TreeModelListener)

removeTreeModelListener

public void removeTreeModelListener(TreeModelListener l)
Removes a listener previously added with addTreeModelListener().

Specified by:
removeTreeModelListener in interface TreeModel
Parameters:
l - the listener to remove
See Also:
addTreeModelListener(javax.swing.event.TreeModelListener)

getTreeModelListeners

public TreeModelListener[] getTreeModelListeners()
Returns an array of all the tree model listeners registered on this model.

Returns:
all of this model's TreeModelListeners or an empty array if no tree model listeners are currently registered
Since:
1.4
See Also:
addTreeModelListener(javax.swing.event.TreeModelListener), removeTreeModelListener(javax.swing.event.TreeModelListener)

fireTreeNodesChanged

protected void fireTreeNodesChanged(Object source,
                                    Object[] path,
                                    int[] childIndices,
                                    Object[] children)
Notifies all listeners that have registered interest for notification on this event type. The event instance is lazily created using the parameters passed into the fire method.

Parameters:
source - the node being changed
path - the path to the root node
childIndices - the indices of the changed elements
children - the changed elements
See Also:
EventListenerList

fireTreeNodesInserted

protected void fireTreeNodesInserted(Object source,
                                     Object[] path,
                                     int[] childIndices,
                                     Object[] children)
Notifies all listeners that have registered interest for notification on this event type. The event instance is lazily created using the parameters passed into the fire method.

Parameters:
source - the node where new elements are being inserted
path - the path to the root node
childIndices - the indices of the new elements
children - the new elements
See Also:
EventListenerList

fireTreeNodesRemoved

protected void fireTreeNodesRemoved(Object source,
                                    Object[] path,
                                    int[] childIndices,
                                    Object[] children)
Notifies all listeners that have registered interest for notification on this event type. The event instance is lazily created using the parameters passed into the fire method.

Parameters:
source - the node where elements are being removed
path - the path to the root node
childIndices - the indices of the removed elements
children - the removed elements
See Also:
EventListenerList

fireTreeStructureChanged

protected void fireTreeStructureChanged(Object source,
                                        Object[] path,
                                        int[] childIndices,
                                        Object[] children)
Notifies all listeners that have registered interest for notification on this event type. The event instance is lazily created using the parameters passed into the fire method.

Parameters:
source - the node where the tree model has changed
path - the path to the root node
childIndices - the indices of the affected elements
children - the affected elements
See Also:
EventListenerList

getListeners

public <T extends EventListener> T[] getListeners(Class<T> listenerType)
Returns an array of all the objects currently registered as FooListeners upon this model. FooListeners are registered using the addFooListener method.

You can specify the listenerType argument with a class literal, such as FooListener.class. For example, you can query a DefaultTreeModel m for its tree model listeners with the following code:

TreeModelListener[] tmls = (TreeModelListener[])(m.getListeners(TreeModelListener.class));
If no such listeners exist, this method returns an empty array.

Parameters:
listenerType - the type of listeners requested; this parameter should specify an interface that descends from java.util.EventListener
Returns:
an array of all objects registered as FooListeners on this component, or an empty array if no such listeners have been added
Throws:
ClassCastException - if listenerType doesn't specify a class or interface that implements java.util.EventListener
Since:
1.3
See Also:
getTreeModelListeners()

Java™ Platform
Standard Ed. 6

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