    001    /* ===========================================================
    002     * JFreeChart : a free chart library for the Java(tm) platform
    003     * ===========================================================
    004     *
    005     * (C) Copyright 2000-2007, by Object Refinery Limited and Contributors.
    006     *
    007     * Project Info:  http://www.jfree.org/jfreechart/index.html
    008     *
    009     * This library is free software; you can redistribute it and/or modify it
    010     * under the terms of the GNU Lesser General Public License as published by
    011     * the Free Software Foundation; either version 2.1 of the License, or
    012     * (at your option) any later version.
    013     *
    014     * This library is distributed in the hope that it will be useful, but
    015     * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
    016     * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
    017     * License for more details.
    018     *
    019     * You should have received a copy of the GNU Lesser General Public
    020     * License along with this library; if not, write to the Free Software
    021     * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
    022     * USA.
    023     *
    024     * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
    025     * in the United States and other countries.]
    026     *
    027     * ----------------
    028     * RootHandler.java
    029     * ----------------
    030     * (C) Copyright 2003-2007, by Object Refinery Limited and Contributors.
    031     *
    032     * Original Author:  David Gilbert (for Object Refinery Limited);
    033     * Contributor(s):   -;
    034     *
    035     * Changes
    036     * -------
    037     * 23-Jan-2003 : Version 1 (DG);
    038     *
    039     */
    040
    041    package org.jfree.data.xml;
    042
    043    import java.util.Stack;
    044
    045    import org.xml.sax.SAXException;
    046    import org.xml.sax.helpers.DefaultHandler;
    047
    048    /**
    049     * A SAX handler that delegates work to sub-handlers.
    050     */
    051    public class RootHandler extends DefaultHandler implements DatasetTags {
    052
    053        /** The sub-handlers. */
    054        private Stack subHandlers;
    055
    056        /**
    057         * Creates a new handler.
    058         */
    059        public RootHandler() {
    060            this.subHandlers = new Stack();
    061        }
    062
    063        /**
    064         * Returns the stack of sub handlers.
    065         *
    066         * @return The sub-handler stack.
    067         */
    068        public Stack getSubHandlers() {
    069            return this.subHandlers;
    070        }
    071
    072        /**
    073         * Receives some (or all) of the text in the current element.
    074         *
    075         * @param ch  character buffer.
    076         * @param start  the start index.
    077         * @param length  the length of the valid character data.
    078         *
    079         * @throws SAXException for errors.
    080         */
    081        public void characters(char[] ch, int start, int length)
    082            throws SAXException {
    083            DefaultHandler handler = getCurrentHandler();
    084            if (handler != this) {
    085                handler.characters(ch, start, length);
    086            }
    087        }
    088
    089        /**
    090         * Returns the handler at the top of the stack.
    091         *
    092         * @return The handler.
    093         */
    094        public DefaultHandler getCurrentHandler() {
    095            DefaultHandler result = this;
    096            if (this.subHandlers != null) {
    097                if (this.subHandlers.size() > 0) {
    098                    Object top = this.subHandlers.peek();
    099                    if (top != null) {
    100                        result = (DefaultHandler) top;
    101                    }
    102                }
    103            }
    104            return result;
    105        }
    106
    107        /**
    108         * Pushes a sub-handler onto the stack.
    109         *
    110         * @param subhandler  the sub-handler.
    111         */
    112        public void pushSubHandler(DefaultHandler subhandler) {
    113            this.subHandlers.push(subhandler);
    114        }
    115
    116        /**
    117         * Pops a sub-handler from the stack.
    118         *
    119         * @return The sub-handler.
    120         */
    121        public DefaultHandler popSubHandler() {
    122            return (DefaultHandler) this.subHandlers.pop();
    123        }
    124
    125    }