import org.xml.sax.*;
import org.xml.sax.helpers.*;
import java.util.StringTokenizer;

/** A SAX handler that prints out the start tags, end tags,
 *  and first word of tag body. Indents two spaces
 *  for each nesting level.
 *
 *  Taken from Core Web Programming from 
 *  Prentice Hall and Sun Microsystems Press,
 *  http://www.corewebprogramming.com/.
 *  © 2001 Marty Hall and Larry Brown;
 *  may be freely used or adapted  
 */

public class PrintHandler extends DefaultHandler {
  private int indentation = 0;

  /** When you see a start tag, print it out and then
   *  increase indentation by two spaces. If the
   *  element has attributes, place them in parens
   *  after the element name.
   */
  public void startElement(String namespaceUri,
                           String localName,
                           String qualifiedName,
                           Attributes attributes)
      throws SAXException {
    indent(indentation);
    System.out.print("Start tag: " + qualifiedName);
    int numAttributes = attributes.getLength();
    // For <someTag> just print out "someTag". But for
    // <someTag att1="Val1" att2="Val2">, print out
    // "someTag (att1=Val1, att2=Val2).
    if (numAttributes > 0) {
      System.out.print(" (");
      for(int i=0; i<numAttributes; i++) {
        if (i>0) {
          System.out.print(", ");
        }
        System.out.print(attributes.getQName(i) + "=" +
                         attributes.getValue(i));
      }
      System.out.print(")");
    }
    System.out.println();
    indentation = indentation + 2;
  }

  /** When you see the end tag, print it out and decrease
   *  indentation level by 2.
   */
  
  public void endElement(String namespaceUri,
                         String localName,
                         String qualifiedName)
      throws SAXException {
    indentation = indentation - 2;
    indent(indentation);
    System.out.println("End tag: " + qualifiedName);
  }

  /** Print out the first word of each tag body. */
  
  public void characters(char[] chars,
                         int startIndex,
                         int length) {
    String data = new String(chars, startIndex, length);
    // Whitespace makes up default StringTokenizer delimeters
    StringTokenizer tok = new StringTokenizer(data);
    if (tok.hasMoreTokens()) {
      indent(indentation);
      System.out.print(tok.nextToken());
      if (tok.hasMoreTokens()) {
        System.out.println("...");
      } else {
        System.out.println();
      }
    }
  }

  private void indent(int indentation) {
    for(int i=0; i<indentation; i++) {
      System.out.print(" ");
    }
  }
}