SimpleSaxHandler.java

package org.gbif.dwca.io;

import java.util.regex.Pattern;

import org.apache.commons.lang3.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;

/**
 * A simple metadata sax base handler that collects all character data inside elements into a string buffer, resetting
 * the buffer with every element start and storing the string version of the buffer in this.content when the end of the
 * element is reached.
 * Make sure to call the super methods when implementing this handler!
 *
 * @author markus
 *
 */
public abstract class SimpleSaxHandler extends DefaultHandler {
  protected final Logger log = LoggerFactory.getLogger(getClass());
  protected String content;
  private StringBuffer chars;
  private Pattern normWhitespace = Pattern.compile("\\s+");
  protected String parents = "";

  @Override
  public void characters(char[] ch, int start, int length) {
    chars.append(ch, start, length);
  }

  @Override
  public void endElement(String uri, String localName, String qName) throws SAXException {
    content = StringUtils.trimToNull(chars.toString());
    // norm whitespace
    if (content != null) {
      content = normWhitespace.matcher(content).replaceAll(" ");
    }
    parents = parents.substring(0, parents.length() - localName.length() - 1);
  }

  @Override
  public void startDocument() {
    parents = "";
  }

  @Override
  public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {
    chars = new StringBuffer();
    parents += "/" + localName.toLowerCase();
  }

  @Override
  public String toString() {
    return getClass().getSimpleName();
  }

}