001/*
002 * Copyright (c) 2005 Einar Pehrson, Malin Johansson and Sofia Nilsson
003 *
004 * This file is part of
005 * CleanSheets Extension for Dependency Trees
006 *
007 * CleanSheets Extension for Dependency Trees is free software; you can
008 * redistribute it and/or modify it under the terms of the GNU General Public
009 * License as published by the Free Software Foundation; either version 2 of
010 * the License, or (at your option) any later version.
011 *
012 * CleanSheets Extension for Dependency Trees is distributed in the hope that
013 * it will be useful, but WITHOUT ANY WARRANTY; without even the implied
014 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
015 * See the GNU General Public License for more details.
016 *
017 * You should have received a copy of the GNU General Public License
018 * along with CleanSheets Extension for Dependency Trees; if not, write to the
019 * Free Software Foundation, Inc., 59 Temple Place, Suite 330,
020 * Boston, MA  02111-1307  USA
021 */
022package csheets.ext.deptree;
023
024import javax.swing.tree.DefaultMutableTreeNode;
025import javax.swing.tree.DefaultTreeModel;
026
027import csheets.core.Cell;
028
029/**
030 * A tree node for a cell, to which child nodes are added dynamically
031 * when the node is expanded.
032 * @author Einar Pehrson
033 */
034public abstract class CellNode extends DefaultMutableTreeNode {
035
036        /** The cell of the node. */
037        private Cell cell;
038
039        /** If child nodes for the node's references have been added. */
040        private boolean populated = false;
041
042        /** The data model to which the node belongs */
043        protected DefaultTreeModel treeModel;
044
045        /**
046         * Creates a new cell node.
047         * @param cell the cell of the node
048         * @param treeModel the data model to which the node belongs
049         */
050        public CellNode(Cell cell, DefaultTreeModel treeModel) {
051                super(cell);
052
053                // Stores members
054                this.cell = cell;
055                this.treeModel = treeModel;
056        }
057
058        /**
059         * Returns the cell of the node.
060         * @return the cell of the node.
061         */
062        public Cell getCell() {
063                return cell;
064        }
065
066        /**
067         * Populates the cell node by adding child nodes for all its references.
068         */
069        public void populate() {
070                if (!populated) {
071                        populated = true;
072                        addChildren();
073                        treeModel.nodeStructureChanged(this);
074                }
075        }
076
077        /**
078         * Adds children to the node. Invoked once, when the node is populated.
079         */
080        protected abstract void addChildren();
081}