annotate java/src/uk/ac/qmul/eecs/ccmi/checkboxtree/CheckBoxTree.java @ 1:e3935c01cde2 tip

moved license of PdPersistenceManager to the beginning of the file

/*  
 CCmI Editor - A Collaborative Cross-Modal Diagram Editing Tool
  
 Copyright (C) 2011  Queen Mary University of London (http://ccmi.eecs.qmul.ac.uk/)

 This program is free software: you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
 the Free Software Foundation, either version 3 of the License, or
 (at your option) any later version.

 This program 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 General Public License for more details.

 You should have received a copy of the GNU General Public License
 along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/
package uk.ac.qmul.eecs.ccmi.checkboxtree;

import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.io.IOException;
import java.io.InputStream;
import java.util.Enumeration;

import javax.swing.JTree;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.DefaultTreeModel;
import javax.swing.tree.TreePath;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;

import org.xml.sax.SAXException;


/**
 * A JTree containing {@code CheckBoxTreeNode} nodes. The tree is built according to an XML file
 * passed as argument to the constructor.
 * The XML file hierarchical structure reflects the structure of the tree. XML tag name can be 
 * either {@code selectable} or {@code unselectable}. The former representing tree nodes with a check
 * box associated to it, and the latter a normal tree node, much as a {@link DefaultMutableTreeNode}. 
 * Either tags must have an attribute {@code value}, representing the name of the node which will be displayed
 * in the tree. Here is an example of a simple XML file, representing a tree with the tree root (non selectable) having
 * three children, the first of which has, in turn, a child. all the descendants of the root are selectable, but the 
 * first child.   
 *    
 * <pre>
 * {@code
 * 	<?xml version="1.0" encoding="utf-8"?>
 *  <unselectable value="root">
 *   <unselectable value="first child"/>
 *   <selectable value="second child"/>
 *   <selectable value "third child">
 *     <selectable value="grand child"/>
 *   </selectable>
 *  </unselectable>
 * }
 * </pre>   
 * 
 * @see CheckBoxTreeNode 
 */
@SuppressWarnings("serial")
public class CheckBoxTree extends JTree {
	public CheckBoxTree(InputStream stream, SetProperties values){
		super(new DefaultTreeModel(new DefaultMutableTreeNode()));
		this.properties = values;
		getAccessibleContext().setAccessibleName("tree");
		treeModel =  (DefaultTreeModel)getModel();
		setCellRenderer(new CheckBoxTreeCellRenderer());
		buildTree(stream);
		/* mouse listener to toggle the selected tree node */
		addMouseListener(new MouseAdapter(){
			@Override
			public void mousePressed(MouseEvent e){
				TreePath path = getPathForLocation(e.getX(),e.getY());
				if(path == null)
					return;
				CheckBoxTreeNode treeNode = (CheckBoxTreeNode)path.getLastPathComponent();
				toggleSelection(treeNode);
			}
		});
	}
	
	/**
	 * Builds a CheckBoxTree out of an xml file passed as argument. All the nodes 
	 * of the tree are marked unchecked. 
	 * 
	 * @param stream an input stream to an xml file
	 */
	public CheckBoxTree(InputStream stream){
		this(stream,null);
	}
	
	/* use a sax parser to build the tree, if an error occurs during the parsing it just stops */
	private void buildTree(InputStream stream){
		SAXParserFactory factory = SAXParserFactory.newInstance();
		try {
			SAXParser saxParser = factory.newSAXParser();
			XMLHandler handler = new XMLHandler((DefaultTreeModel)getModel(),properties);
			saxParser.parse(stream, handler);
		} catch (IOException e) {
			e.printStackTrace();
			return;
		} catch (ParserConfigurationException e) {
			e.printStackTrace();
			return;
		} catch (SAXException e) {
			e.printStackTrace();
			return;
		}
	}
	
	/**
	 * Returns a reference to the properties holding which nodes of the tree are currently checked.  
	 * @return the properties or {@code null} if the constructor with no properties was used. 
	 */
	public SetProperties getProperties(){
		return properties;
	}
	
	/**
	 * Toggle the check box of the tree node passed as argument. If the tree node 
	 * is not a leaf, then all its descendants will get the new value it. That is, 
	 * if the tree node becomes selected as a result of the call, then all the descendants 
	 * will become in turn selected (regardless of their previous state). If it becomes
	 * unselected, the descendants will become unselected as well.   
	 * 
	 * @param treeNode the tree node to toggle
	 */
	public void toggleSelection(CheckBoxTreeNode treeNode){
		if(treeNode.isSelectable()){
			boolean selection = !treeNode.isSelected();
			treeNode.setSelected(selection);
			if(selection)
				properties.add(treeNode.getPathAsString());
			else
				properties.remove(treeNode.getPathAsString());
			treeModel.nodeChanged(treeNode);
			if(!treeNode.isLeaf()){
				for( @SuppressWarnings("unchecked")
					Enumeration<CheckBoxTreeNode> enumeration = treeNode.depthFirstEnumeration(); enumeration.hasMoreElements();){
					CheckBoxTreeNode t = enumeration.nextElement();
					t.setSelected(selection);
					if(selection)
						properties.add(t.getPathAsString());
					else
						properties.remove(t.getPathAsString());
					treeModel.nodeChanged(t);
				}
			}
		}
	}
	
	private SetProperties properties;
	private DefaultTreeModel treeModel; 
}