Module java.desktop
Package javax.swing.tree

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 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: