/* class DefaultTreeModel
*
* Copyright (C) 2003 R M Pitman
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
package charvax.swing.tree;
import java.util.ArrayList;
import charvax.swing.event.TreeModelListener;
/** (UNDER CONSTRUCTION) A simple tree data model that uses TreeNodes.
*/
public class DefaultTreeModel
implements TreeModel
{
/** Creates a tree in which any node can have children.
*/
DefaultTreeModel(TreeNode root)
{
this(root, false);
}
/** Creates a tree specifying whether any node can have children, or
* whether only certain nodes can have children.
*/
DefaultTreeModel(TreeNode root, boolean asksAllowsChildren)
{
_root = root;
_asksAllowsChildren = asksAllowsChildren;
}
/** Returns the root of the tree.
* Returns null only if the tree has no nodes.
*/
public Object getRoot()
{
return _root;
}
/** 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)).
*/
public Object getChild(Object parent, int index)
{
TreeNode parentNode = (TreeNode) parent;
return parentNode.getChildAt(index);
}
/** 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.
*/
public int getChildCount(Object parent)
{
TreeNode parentNode = (TreeNode) parent;
return parentNode.getChildCount();
}
/** Returns true if node is a leaf. The way the test is performed
* depends on the asksAllowsChildren setting.
*/
public boolean isLeaf(Object node_)
{
TreeNode node = (TreeNode) node_;
if (_asksAllowsChildren) {
return ( ! node.getAllowsChildren());
}
else {
return (node.getChildCount() == 0);
}
}
/** Called when the user has altered the value for the item
* identified by path to newValue. If newValue signifies a truly new
* value the model should post a treeNodesChanged event.
*/
public void valueForPathChanged(TreePath path, Object newValue)
{
}
/** Adds a listener for the TreeModelEvent posted after the tree changes.
*/
public void addTreeModelListener(TreeModelListener l)
{
}
/** Removes a listener previously added with addTreeModelListener.
*/
public void removeTreeModelListener(TreeModelListener l)
{
}
//====================================================================
// INSTANCE VARIABLES
/** 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.<p>
*
* If this value is false, then any node which has no children is a
* leaf node, and any node may acquire children.
*/
protected boolean _asksAllowsChildren ;
protected ArrayList<TreeModelListener> _listeners;
protected TreeNode _root;
}