import java.util.Stack;

import org.xml.sax.Attributes;
import org.xml.sax.Locator;
import org.xml.sax.SAXException;
import org.xml.sax.SAXParseException;
import org.xml.sax.helpers.DefaultHandler;

import RssChannel.RssItem;
import RssChannel.RssImage;
import RssChannel.RssTextInput;

/**
 * Unmarshaling SAX Events into RSS Data
 */
public class RssConsumer extends DefaultHandler {
    private RssChannel		channel;
    private RssItem		item;
    private RssImage		image;
    private RssTextInput	input;

    private Stack		stack;
    private Locator		locator;

    public RssChannel getChannel ()
	{ return channel; }

    private String getCurrentElementName ()
	{ return (String) stack.peek (); }

    // only need a handful of ContentHandler methods

    public void setDocumentLocator (Locator l)
	{ locator = l; }

    public void startDocument () throws SAXException
    {
	channel = new RssChannel ();
	if (locator != null)
	    channel.sourceUri = locator.getSystemId ();
	stack = new Stack ();
    }

    public void startElement (
	String		namespace,
	String		local,
	String		name,
	Attributes	attrs
    ) throws SAXException
    {
	stack.push (name);

	if ("item".equals (name))
	    item = new RssItem ();
	else if ("image".equals (name))
	    image = new RssImage ();
	else if ("textinput".equals (name))
	    input = new RssTextInput ();
	// parser misconfigured?
	else if (name.length () == 0)
	    throw new SAXParseException ("XML names not available", locator);
    }

    public void characters (char buf [], int off, int len)
    throws SAXException
    {
	String	top = getCurrentElementName ();
	String	value = new String (buf, off, len);

	if ("title".equals (top)) {
	    if (item != null)
		item.title += value;
	    else if (image != null)
		image.title += value;
	    else if (input != null)
		input.title += value;
	    else
		channel.title += value;
	} else if ("description".equals (top)) {
	    if (item != null)
		item.description += value;
	    else if (image != null)
		image.description += value;
	    else if (input != null)
		input.description += value;
	    else
		channel.description += value;
	} else if ("link".equals (top)) {
	    if (item != null)
		item.link += value;
	    else if (image != null)
		image.link += value;
	    else if (input != null)
		input.link += value;
	    else
		channel.link += value;

	} else if ("url".equals (top)) {
	    image.url += value;

	} else if ("name".equals (top)) {
	    input.name += value;

	} else if ("language".equals (top)) {
	    channel.language += value;
	} else if ("managingEditor".equals (top)) {
	    channel.managingEditor += value;
	} else if ("webMaster".equals (top)) {
	    channel.webMaster += value;

	} else if ("copyright".equals (top)) {
	    channel.copyright += value;
	} else if ("lastBuildDate".equals (top)) {
	    channel.lastBuildDate += value;
	} else if ("pubDate".equals (top)) {
	    channel.pubDate += value;
	} else if ("docs".equals (top)) {
	    channel.docs += value;
	} else if ("rating".equals (top)) {
	    channel.rating += value;

	} // else ignore ... skipDays and so on.
    }

    public void endElement (
	String		namespace,
	String		local,
	String		name
    ) throws SAXException
    {
	if ("item".equals (name)) {
	    // patch item.link
	    channel.items.addElement (item);
	    item = null;
	} else if ("image".equals (name)) {
	    // patch image.link
	    // (patch image.url)
	    channel.image = image;
	    image = null;
	} else if ("textinput".equals (name)) {
	    // patch input.link
	    channel.textinput = input;
	    input = null;
	} else if ("channel".equals (name)) {
	    // patch channel.link
	}
    }
}