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Class DefaultTreeModel

java.lang.Object

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 JavaBeans has been added to the java.beans package. Please see XMLEncoder.

Field Summary

Modifier and Type	Field	Description
`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

Constructor	Description
`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

Modifier and Type	Method	Description
`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 `FooListener`s 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 children's 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 `TreeNode`s upon which this model depends.
`void`	`reload(TreeNode node)`	Invoke this method if you've modified the `TreeNode`s 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 declared in class java.lang.Object

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

Field Details

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:

Constructor Details

DefaultTreeModel

@ConstructorProperties("root") 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

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:

Method Details

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.

Parameters:: newValue - if 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:

setRoot

public void setRoot(TreeNode root)

Sets the root to root. A null root implies the tree is to display nothing, and is legal.

Parameters:: root - new value of tree root

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; index - index of child to be returned
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 asksAllowsChildren setting.

Specified by:

isLeaf in interface TreeModel

Parameters:

node - the node to check

Returns:

true if the node is a leaf node

See Also:

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.

Parameters:: newChild - child node to be inserted; parent - node to which children new node will be added; index - index of parent's children

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.

Parameters:: node - the node to be removed from its parent

nodeChanged

public void nodeChanged(TreeNode node)

Invoke this method after you've changed how node is to be represented in the tree.

Parameters:: node - the changed node

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.

Parameters:: node - parent node which children count been incremented; childIndices - indexes of inserted children

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.

Parameters:: node - parent node which childred were removed; childIndices - indexes of removed children; removedChildren - 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.

Parameters:: node - changed node; childIndices - indexes of changed children

nodeStructureChanged

public void nodeStructureChanged(TreeNode node)

Invoke this method if you've totally changed the children of node and its children's children... This will post a treeStructureChanged event.

Parameters:: node - changed node

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
Returns:: an array of TreeNodes giving the path from the root

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

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:

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:

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 source of the TreeModelEvent; typically this; path - the path to the parent of the nodes that changed; use null to identify the root has changed; childIndices - the indices of the changed elements; children - the changed elements

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 source of the TreeModelEvent; typically this; path - the path to the parent the nodes were added to; childIndices - the indices of the new elements; children - the new elements

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 source of the TreeModelEvent; typically this; path - the path to the parent the nodes were removed from; childIndices - the indices of the removed elements; children - the removed elements

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 source of the TreeModelEvent; typically this; path - the path to the parent of the structure that has changed; use null to identify the root has changed; childIndices - the indices of the affected elements; children - the affected elements

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.

Type Parameters:

T - the listener type

Parameters:

listenerType - the type of listeners requested

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:

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