package examples.jms.messageformat;

import java.util.Hashtable;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.SAXParseException;
import org.xml.sax.helpers.DefaultHandler;

/**
 * This class extends <tt>HandlerBase</tt> and is used to handle events
 * created as an XML document is parsed by a SAX compliant
 * parser.
 *
 * @author Copyright (c) 2005 by BEA Systems, Inc. All Rights Reserved.
 */
public class RequestHandler extends DefaultHandler {

  /** stocktrade document model */
  private Hashtable<String,String> trade;

  /** Default constructor. */
  public RequestHandler() {}


  //==========================================================================
  // DocumentHandler methods
  //==========================================================================

    // Amount to indent
    private String indentString = "    ";
    private int indentLevel = 0;

   /**
   * Receives notification of the beginning of the XML document.
   * Starts printing information to the shell from which you started the
   * WebLogic server and starts a new trade hashtable to store trade information.
   *
   * @exception SAXException If an error occurred starting to parse the XML doc
   */
  public void startDocument() throws SAXException {
    nl();
    nl();
    trade = new Hashtable<String,String>();
    log("START DOCUMENT");
    nl();
    log("<?xml version='1.0' encoding='UTF-8'?>");
  }

  /**
   * Receives notification of the end of the XML document.  Prints a
   * final message to the shell from which you started the WebLogic server.
   *
   * @exception SAXException If an error occurred while parsing the XML doc
   */
  public void endDocument() throws SAXException {
    nl();
    log("END DOCUMENT");
    try {
      nl();
    } catch (Exception e) {
      throw new SAXException ("I/O error", e);
    }
  }

  /**
   * Receives notification of the start of an element.   Prints out the
   * name and value of the element, properly indented, to the shell from
   * which you started the WebLogic server.  Updates the trade hashtable
   * with the trade information.
   *
   * @param uri
   * @param localName
   * @param qName
   * @param attrs
   * @exception    SAXException if an error occurred while parsing the XML doc
   */
  public void startElement(String uri, String localName, String qName,
                           Attributes attrs)
    throws SAXException
  {
    indentLevel++;
    nl();
    log("ELEMENT: " +qName);
    	if (attrs != null) {
        for (int i = 0; i < attrs.getLength (); i++) {
          nl();
          trade.put(attrs.getQName(i), attrs.getValue(i));
          log("   ATTR: " +attrs.getQName(i)+" = "+attrs.getValue(i));
        }
      }
   }

   /**
    * Receives notification of the end of an element.   Prints
    * notice to the shell from which you started the WebLogic server.
    *
    * @param name the string name of the element
    * @exception SAXException If an error occurred while parsing the XML doc
    */
   public void endElement(String name) throws SAXException {
     nl();
     log ("END_ELM: " + name);
     indentLevel--;
   }

  /**
  * Receives notification of character data inside an element. Prints out
  * characters to the shell from which you started the WebLogic server.
  *
  * @param buf     array of characters
  * @param offset  the start position in the character array
  * @param len     the number of characters to use from the array
  * @exception     SAXException if an error occurred while parsing the XML doc
  */
  public void characters (char buf [], int offset, int len)
    throws SAXException
  {
    nl();
    String s = new String(buf, offset, len);
    if (!s.trim().equals("")) log ("CHARS:   " + s);
  }

   //===========================================================
   // Helpers ...
   //===========================================================

 /**
  * Starts a new line and indents the next line appropriately.
  *
  * @exception SAXException If an error occurred while parsing the XML doc
  */
  private void nl () throws SAXException {
    String lineEnd =  System.getProperty("line.separator");
    try {
      System.out.print(lineEnd);
      for (int i=0; i < indentLevel; i++) log(indentString);
    } catch (Exception e) {
      throw new SAXException ("I/O error", e);
    }
  }

  //=============================================================
  // ErrorHandler methods
  //=============================================================

   /**
    * Receives notification of a recoverable parser error.
    *
    * @param x   the parser exception that occurred
    * @exception SAXException if an error occurred while receiving the original error
    */
   public void error (SAXParseException x) throws SAXException {
     throw x;
   }

  /** Returns parsed data as a hashtable. */
  public Hashtable<String,String> getData() { return trade; }

  private void log(String str) { System.out.println(str); }
}