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* CruiseControl, a Continuous Integration Toolkit
* Copyright (c) 2001, ThoughtWorks, Inc.
* 200 E. Randolph, 25th Floor
* Chicago, IL 60601 USA
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package net.sourceforge.cruisecontrol.util;
import org.apache.log4j.Logger;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.XMLReader;
import org.xml.sax.helpers.XMLFilterImpl;
/**
* This filter deletes elements without child nodes (text or elements) with
* the given tagname.
* It is used by the AntBuilder to get rid of empty tags
* generated by Ant's XmlLogger, like empty messages and tasks.
*
* @author <a href="mailto:joriskuipers@xs4all.nl">Joris Kuipers</a>
*/
public class EmptyElementFilter extends XMLFilterImpl {
private static final Logger LOG = Logger.getLogger(EmptyElementFilter.class);
private final String tagName;
private boolean checkingTag = false;
// atts for storing the Element info
private String messageUri;
private String messageQName;
private Attributes messageAtts;
/**
* Constructor for EmptyElementFilter.
*/
public EmptyElementFilter(String tagName) {
super();
this.tagName = tagName;
}
/**
* Constructor for EmptyElementFilter.
* @param arg0
*/
public EmptyElementFilter(String tagName, XMLReader arg0) {
super(arg0);
this.tagName = tagName;
}
/**
* @see org.xml.sax.ContentHandler#characters(char[], int, int)
*/
public void characters(char[] ch, int start, int length) throws SAXException {
if (checkingTag) {
cancelCheck();
}
super.characters(ch, start, length);
}
/**
* @see org.xml.sax.ContentHandler#endElement(String, String, String)
*/
public void endElement(String uri, String localName, String qName) throws SAXException {
if (checkingTag) {
// localName must be tagName now, and we're dealing with an empty tag
checkingTag = false;
LOG.debug("Skipping empty <" + localName + ">-tag");
} else {
super.endElement(uri, localName, qName);
}
}
/**
* @see org.xml.sax.ContentHandler#startElement(String, String, String, Attributes)
*/
public void startElement(String uri, String localName, String qName, Attributes atts) throws SAXException {
if (checkingTag) {
cancelCheck();
}
if (localName.equals(tagName)) {
// hold the delegation until we're sure this is not an empty tag
checkingTag = true;
messageUri = uri;
messageQName = qName;
messageAtts = atts;
} else {
super.startElement(uri, localName, qName, atts);
}
}
private void cancelCheck() throws SAXException {
// delegate the event that we've held back and stop checking
super.startElement(messageUri, tagName, messageQName, messageAtts);
checkingTag = false;
}
}