/* ===========================================================

 * JFreeChart : a free chart library for the Java(tm) platform

 * ===========================================================

 *

 * (C) Copyright 2000-2004, 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., 59 Temple Place, Suite 330,

 * Boston, MA 02111-1307, USA.

 *

 * [Java is a trademark or registered trademark of Sun Microsystems, Inc. 

 * in the United States and other countries.]

 *

 * ----------------

 * ItemHandler.java

 * ----------------

 * (C) Copyright 2003, by Object Refinery Limited and Contributors.

 *

 * Original Author:  David Gilbert (for Object Refinery Limited);

 * Contributor(s):   -;

 *

 * $Id: ItemHandler.java,v 1.1 2004/08/31 15:35:26 mungady Exp $

 *

 * Changes (from 21-Jun-2001)

 * --------------------------

 * 23-Jan-2003 : Version 1 (DG);

 *

 */



package org.jfree.data.xml;



import org.xml.sax.Attributes;

import org.xml.sax.SAXException;

import org.xml.sax.helpers.DefaultHandler;



/**

 * A handler for reading key-value items.

 *

 */

public class ItemHandler extends DefaultHandler implements DatasetTags {



    /** The root handler. */

    private RootHandler root;



    /** The parent handler (can be the same as root, but not always). */

    private DefaultHandler parent;



    /** The key. */

    private Comparable key;



    /** The value. */

    private Number value;



    /**

     * Creates a new item handler.

     *

     * @param root  the root handler.

     * @param parent  the parent handler.

     */

    public ItemHandler(final RootHandler root, final DefaultHandler parent) {

        this.root = root;

        this.parent = parent;

        this.key = null;

        this.value = null;

    }



    /**

     * Returns the key that has been read by the handler, or <code>null</code>.

     *

     * @return The key.

     */

    public Comparable getKey() {

        return this.getKey();

    }



    /**

     * Sets the key.

     *

     * @param key  the key.

     */

    public void setKey(final Comparable key) {

        this.key = key;

    }



    /**

     * Returns the key that has been read by the handler, or <code>null</code>.

     *

     * @return The value.

     */

    public Number getValue() {

        return this.value;

    }



    /**

     * Sets the value.

     *

     * @param value  the value.

     */

    public void setValue(final Number value) {

        this.value = value;

    }



    /**

     * The start of an element.

     *

     * @param namespaceURI  the namespace.

     * @param localName  the element name.

     * @param qName  the element name.

     * @param atts  the attributes.

     *

     * @throws SAXException for errors.

     */

    public void startElement(final String namespaceURI,

                             final String localName,

                             final String qName,

                             final Attributes atts) throws SAXException {



        if (qName.equals(ITEM_TAG)) {

            final KeyHandler subhandler = new KeyHandler(this.root, this);

            this.root.pushSubHandler(subhandler);

        }

        else if (qName.equals(VALUE_TAG)) {

            final ValueHandler subhandler = new ValueHandler(this.root, this);

            this.root.pushSubHandler(subhandler);

        }

        else {

            throw new SAXException("Expected <Item> or <Value>...found " + qName);

        }



    }



    /**

     * The end of an element.

     *

     * @param namespaceURI  the namespace.

     * @param localName  the element name.

     * @param qName  the element name.

     */

    public void endElement(final String namespaceURI,

                           final String localName,

                           final String qName) {



        if (this.parent instanceof PieDatasetHandler) {

            final PieDatasetHandler handler = (PieDatasetHandler) this.parent;

            handler.addItem(this.key, this.value);

            this.root.popSubHandler();

        }

        else if (this.parent instanceof CategorySeriesHandler) {

            final CategorySeriesHandler handler = (CategorySeriesHandler) this.parent;

            handler.addItem(this.key, this.value);

            this.root.popSubHandler();

        }



    }



}

