source: trunk/gli/src/org/greenstone/gatherer/util/XMLTools.java@ 7979

package org.greenstone.gatherer.util;


import java.io.*;
import java.util.*;
import org.apache.xerces.parsers.*;
import org.apache.xml.serialize.*;
import org.w3c.dom.*;
import org.xml.sax.*;


/** This class is a static class containing useful XML functions */
public class XMLTools
{
   static public ArrayList getChildElementsByTagName(Element parent_element, String element_name)
   {
      ArrayList child_elements = new ArrayList();

      NodeList children_nodelist = parent_element.getChildNodes();
      for (int i = 0; i < children_nodelist.getLength(); i++) {
     Node child_node = children_nodelist.item(i);
     if (child_node.getNodeType() == Node.ELEMENT_NODE && child_node.getNodeName().equals(element_name)) {
        child_elements.add(child_node);
     }
      }

      return child_elements;
   }


   static public String getElementTextValue(Element element)
   {
      // Find the first text node child
      NodeList children_nodelist = element.getChildNodes();
      for (int i = 0; i < children_nodelist.getLength(); i++) {
     Node child_node = children_nodelist.item(i);
     if (child_node.getNodeType() == Node.TEXT_NODE) {
        return child_node.getNodeValue();
     }
      }

      // None found
      return null;
   }


   /** Parse an XML document from a given file */
   static public Document parseXMLFile(File xml_file)
   {
      Document document = null;

      try {
     FileInputStream fis   = new FileInputStream(xml_file);
     InputStreamReader isr = new InputStreamReader(fis, "UTF-8");
     Reader r              = new BufferedReader(isr);
     InputSource isc       = new InputSource(r);
     DOMParser parser      = new DOMParser();
     parser.setFeature("http://xml.org/sax/features/validation", false);
     parser.setFeature("http://apache.org/xml/features/nonvalidating/load-external-dtd", false);
     // May or may not be ignored, the documentation for Xerces is contradictory. If it works then parsing -should- be faster.
     parser.setFeature("http://apache.org/xml/features/dom/defer-node-expansion", true);
     parser.setFeature("http://apache.org/xml/features/dom/include-ignorable-whitespace", false);
     parser.parse(isc);
     document = parser.getDocument();
     isr.close();
     fis.close();
      }
      catch (Exception exception) {
     exception.printStackTrace();
      }

      return document;
   }


   /** Write an XML document to a given file */
   static public void writeXMLFile(File xml_file, Document document)
   {
      try {
     OutputStream os = new FileOutputStream(xml_file);
     // Create an output format for our document.
     OutputFormat f = new OutputFormat(document);
     f.setEncoding("UTF-8");
     f.setIndenting(true);
     f.setLineWidth(0); // Why isn't this working!
     f.setPreserveSpace(false);
     // Create the necessary writer stream for serialization.
     OutputStreamWriter osw = new OutputStreamWriter(os, "UTF-8");
     Writer w               = new BufferedWriter(osw);
     // Generate a new serializer from the above.
     XMLSerializer s        = new XMLSerializer(w, f);
     s.asDOMSerializer();
     // Finally serialize the document to file.
     s.serialize(document);
     // And close.
     os.close();
      }
      catch (Exception exception) {
     exception.printStackTrace();
      }
   }
}