/*
    * $Header: /cvsroot/jdbforms/dbforms/src/org/dbforms/event/datalist/dao/XMLDataResult.java,v 1.18 2005/12/02 12:35:47 hkollmann Exp $
    * $Revision: 1.18 $
    * $Date: 2005/12/02 12:35:47 $
    *
    * DbForms - a Rapid Application Development Framework
    * Copyright (C) 2001 Joachim Peer <joepeer@excite.com>
    *
    * This library is free software; you can redistribute it and/or
   * modify it under the terms of the GNU Lesser General Public
   * License as published by the Free Software Foundation; either
   * version 2.1 of the License, or (at your option) any later version.
   *
   * This library is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with this library; if not, write to the Free Software
   * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
   */
  
  package org.dbforms.event.datalist.dao;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  
  import org.dbforms.config.FieldTypes;
  
  import org.dbforms.dom.DOMFactory;
  
  import org.dbforms.util.TimeUtil;
  import org.dbforms.util.Util;
  
  import org.w3c.dom.Element;
  import org.w3c.dom.Node;
  import org.w3c.dom.xpath.XPathEvaluator;
  import org.w3c.dom.xpath.XPathNSResolver;
  import org.w3c.dom.xpath.XPathResult;
  
  
  
  /***
   * Delegates the whole xpath stuff to this class. Holds the result of an xpath
   * query. Do the mapping between java objects and fields.
   *
   * @author hkk
   */
  public class XMLDataResult {
     private static Log      logCat    = LogFactory.getLog(XMLDataResult.class);
     private Element         root;
     private XPathEvaluator  evaluator;
     private XPathNSResolver resolver;
     private XPathResult     data;
     private boolean         changed = false;
  
     /***
      * Creates a new XMLDataResult object.
      *
      * @param root xml dom object
      * @param qry xpath string to query
      */
     public XMLDataResult(Element root,
                          String  qry) {
        this.root      = root;
        this.evaluator = DOMFactory.instance()
                                   .newXPathEvaluator();
        resolver = evaluator.createNSResolver(root);
  
        // Evaluate the xpath expression.
        data = (XPathResult) evaluator.evaluate(qry, this.root, resolver,
                                                XPathResult.ORDERED_NODE_SNAPSHOT_TYPE,
                                                null);
     }
  
     /***
      * sets the field value of a special node as string. node is decribed by an
      * xpath string
      *
      * @param i node of result to return
      * @param expression xpath string which discribes the field to return
      * @param objectType field type to return
      * @param value value to set
      */
     public void setItemValue(int    i,
                              String expression,
                              int    objectType,
                              Object value) {
     }
  
  
     /***
      * returns the field value of a special node as Object. Node is decribed by
      * an xpath string
      *
      * @param i node of result to return
      * @param expression xpath string which discribes the field to return
      * @param objectType field type to return
     *
     * @return value as Object of selected type
     */
    public Object getItemValue(int    i,
                               String expression,
                               int    objectType) {
       Object result = null;
 
       try {
          Node n = item(i);
 
          if (n != null) {
             XPathResult pdata = (XPathResult) evaluator.evaluate(expression, n,
                                                                 resolver,
                                                                 XPathResult.FIRST_ORDERED_NODE_TYPE,
                                                                 null);
 
             if (pdata != null) {
                n = pdata.getSingleNodeValue();
 
                if (n != null) {
                   switch (objectType) {
                      case FieldTypes.CHAR:
                         result = toString(n);
 
                         break;
 
                      case FieldTypes.FLOAT:
                      case FieldTypes.NUMERIC:
                         result = new Double(toString(n));
 
                         break;
 
                      case FieldTypes.INTEGER:
                         result = new Integer(toString(n));
 
                         break;
 
                      case FieldTypes.DATE:
                      case FieldTypes.TIMESTAMP:
                      case FieldTypes.TIME:
                         result = TimeUtil.parseISO8601Date(toString(n));
 
                         break;
 
                      default:
                         result = toString(n);
 
                         break;
                   }
                }
             }
          }
       } catch (Exception e) {
          logCat.error("getItemValue", e);
       }
 
       return result;
    }
 
 
    /***
     * DOCUMENT ME!
     *
     * @return DOCUMENT ME!
     */
    public Element getRoot() {
       return root;
    }
 
 
    /***
     * DOCUMENT ME!
     *
     * @return DOCUMENT ME!
     */
    public boolean hasChanged() {
       return changed;
    }
 
 
    /***
     * returns the result at index as dom node
     *
     * @param index node of result to return
     *
     * @return the node at index
     */
    public Node item(int index) {
       Node res = null;
 
       if (index < data.getSnapshotLength()) {
          res = data.snapshotItem(index);
       }
 
       return res;
    }
 
 
    /***
     * size of resultset
     *
     * @return size of result set
     */
    public int size() {
       int res = data.getSnapshotLength();
 
       return res;
    }
 
 
    private String toString(Node element) {
       String result = null;
 
       if (element != null) {
          if (element.getNodeType() == Node.TEXT_NODE) {
             result = element.getNodeValue();
          } else {
             for (Node tx = element.getFirstChild(); tx != null;
                        tx = tx.getNextSibling()) {
                result = toString(tx);
 
                if (!Util.isNull(result)) {
                   break;
                }
             }
          }
       }
 
       return result;
    }
 }