// File: xmltest3.java
//
// Author: Rahul Simha
// Version: Feb 11, 2000
//
// Demonstrates node addition and writing XML output.

import com.ibm.xml.parser.*;
import org.w3c.dom.*;
import java.io.*;
import java.util.*;

// An error-handling class passed to the parser that
// overrides the error method.

class MyErrorHandler implements ErrorListener {
  public int error (String fname, int lineno, int charoff,
		    Object key, String mes)
  {
    System.out.println ("ERR:" + fname + " at line " + lineno +
			": " + mes);
    return 1;
  }
}


public class xmltest3 {

  // The method clean removes all nodes with "junk" data.

  public static void clean (Node n)
  {
    boolean remove = false;
    String nodename = n.getNodeName();

    if (nodename != null) {
      // Removing is a possibility only if the node is of type "#text".
      if (nodename.equals ("#text"))
	remove = true;
      else
	remove = false;
    }

    // Extract the node value.
    String valueStr = n.getNodeValue();
    int len = 0;

    // Now trim and check if it needs to be removed.
    if (valueStr != null) {
      valueStr = valueStr.trim();
      len = valueStr.length();
      if (len > 0) {
        // Useful
	remove = false;
        // Put the trimmed string back in.
        n.setNodeValue (valueStr);
      }
    }

    if (remove) {
      // To remove, go to the parent node and delete from there.
      Node p = n.getParentNode();
      p.removeChild (n);
      // Recursively clean.
      clean (p);
      return;
    }

    // Continue exploration.
    if (n.hasChildNodes()) {
      NodeList nl = n.getChildNodes();
      int size = nl.getLength();
      for (int i=0; i<size; i++) {
	clean (nl.item(i));
	size = nl.getLength();
      }
    }
  }


  public static void traverse (Node n)
  {
    System.out.println ("Node: " + n.getNodeName() + " value=" + n.getNodeValue());

    if (n.hasChildNodes()) {
      NodeList nl = n.getChildNodes();
      int size = nl.getLength();
      for (int i=0; i<size; i++)
	traverse (nl.item(i));
    }
  }


  public static Node makeStudent (Node n, String name, String addr, String grade)
  {
    try {
      // Get new data from another file.
      FileReader fr = new FileReader ("newstudent2.xml");
      // Parse it.
      Parser p = new Parser ("newstudent.xml", new MyErrorHandler(), null);
      p.setKeepComment (false);
      p.setPreserveSpace (false);
      TXDocument doc = p.readStream (fr);
      Element root = doc.getDocumentElement ();
      // Check:
      if (root == null) return null;
      clean (root);
      return (Node) root;
    }
    catch (IOException e) {
      System.out.println (e);
      return null;
    }
  }


  static PrintWriter pw_out;

  public static void traverseWrite (Node n, int depth)
  {
    String nodeName = n.getNodeName();
    String nodeValue = n.getNodeValue();
    /* System.out.println ("Node (depth=" + depth + "): " 
			  + nodeName + " value=" +
			  nodeValue); */

    // Pad with enough blanks, depending on nesting depth.
    for (int i=0; i<depth; i++)
      pw_out.print (" ");

    // Decide what to print.
    if (nodeName.startsWith ("#"))
      pw_out.println (" " + nodeValue);
    else
      pw_out.println (" <" + nodeName + ">");

    // Continue printing recursively.
    if (n.hasChildNodes()) {
      NodeList nl = n.getChildNodes();
      int size = nl.getLength();
      for (int i=0; i<size; i++)
	traverseWrite (nl.item(i), depth+1);
    }

    // Add the end tag.
    if (!nodeName.startsWith ("#")) {
      for (int i=0; i<depth; i++)
	pw_out.print (" ");
      pw_out.println (" </" + nodeName + ">");
    }
  }



  public static void main (String[] argv)
  {
    if (argv.length > 0) {
      try {
	FileReader fr = new FileReader (argv[0]);
	Parser p = new Parser (argv[0]);
	p.setKeepComment (false);
	p.setPreserveSpace (false);
	TXDocument doc = p.readStream(fr);
	Element root = doc.getDocumentElement ();

	clean (root);
	System.out.println ("TRAVERSE ...");
	traverse (root);

	System.out.println ("ADDING A NEW STUDENT: ");
	NodeList nl = doc.getElementsByTagName ("STUDENT");
	Node n = nl.item(1);
	Node s = makeStudent (n, "Dangerous Dave", "333 Ouch St", "C");
	Node parent = n.getParentNode();
	parent.appendChild (s);
	System.out.println ("TRAVERSE ...");
	traverse (root);

	// Next, output using the document's print method.
	FileWriter fw = new FileWriter ("studentout.xml");
	PrintWriter pw = new PrintWriter (fw);
	doc.print (pw);
	pw.close();

	// Our own custom writing approach.
	// NOTE: this does not print the DTD, for unknown reasons.
	String charset = "ISO-8859-1";
	String jencode = MIME2Java.convert (charset);
	fw = new FileWriter ("studentout2.xml");
	pw_out = new PrintWriter (fw);
	DTD dtd = doc.getDTD();
	dtd.toXMLString (pw_out);
	pw_out.flush();
	pw_out.close();
      }
      catch (IOException e) {
	System.out.println ("Usage: java xmltest3 <filename>");
      }
    }
    else {
	System.out.println ("Usage: java xmltest3 <filename>");
    }
  }
}