jfreechart example source code file (RootHandler.java)

This example jfreechart source code file (RootHandler.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - jfreechart tags/keywords

datasettags, defaulthandler, defaulthandler, object, object, roothandler, roothandler, sax, saxexception, stack, stack, util

The jfreechart RootHandler.java source code

/* ===========================================================
 * JFreeChart : a free chart library for the Java(tm) platform
 * ===========================================================
 *
 * (C) Copyright 2000-2008, by Object Refinery Limited and Contributors.
 *
 * Project Info:  http://www.jfree.org/jfreechart/index.html
 *
 * 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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
 * USA.
 *
 * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
 * in the United States and other countries.]
 *
 * ----------------
 * RootHandler.java
 * ----------------
 * (C) Copyright 2003-2008, by Object Refinery Limited and Contributors.
 *
 * Original Author:  David Gilbert (for Object Refinery Limited);
 * Contributor(s):   -;
 *
 * Changes
 * -------
 * 23-Jan-2003 : Version 1 (DG);
 *
 */

package org.jfree.data.xml;

import java.util.Stack;

import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;

/**
 * A SAX handler that delegates work to sub-handlers.
 */
public class RootHandler extends DefaultHandler implements DatasetTags {

    /** The sub-handlers. */
    private Stack subHandlers;

    /**
     * Creates a new handler.
     */
    public RootHandler() {
        this.subHandlers = new Stack();
    }

    /**
     * Returns the stack of sub handlers.
     *
     * @return The sub-handler stack.
     */
    public Stack getSubHandlers() {
        return this.subHandlers;
    }

    /**
     * Receives some (or all) of the text in the current element.
     *
     * @param ch  character buffer.
     * @param start  the start index.
     * @param length  the length of the valid character data.
     *
     * @throws SAXException for errors.
     */
    public void characters(char[] ch, int start, int length)
        throws SAXException {
        DefaultHandler handler = getCurrentHandler();
        if (handler != this) {
            handler.characters(ch, start, length);
        }
    }

    /**
     * Returns the handler at the top of the stack.
     *
     * @return The handler.
     */
    public DefaultHandler getCurrentHandler() {
        DefaultHandler result = this;
        if (this.subHandlers != null) {
            if (this.subHandlers.size() > 0) {
                Object top = this.subHandlers.peek();
                if (top != null) {
                    result = (DefaultHandler) top;
                }
            }
        }
        return result;
    }

    /**
     * Pushes a sub-handler onto the stack.
     *
     * @param subhandler  the sub-handler.
     */
    public void pushSubHandler(DefaultHandler subhandler) {
        this.subHandlers.push(subhandler);
    }

    /**
     * Pops a sub-handler from the stack.
     *
     * @return The sub-handler.
     */
    public DefaultHandler popSubHandler() {
        return (DefaultHandler) this.subHandlers.pop();
    }

}