import java.io.*;
import java.awt.*;
import java.net.*;
import java.awt.event.*;
import org.xml.sax.*;
import org.w3c.dom.*;
import com.sun.xml.parser.*;
import com.sun.xml.tree.*;
import org.xml.sax.helpers.*;

/*
 * XmlView2 - a small AWT GUI program that illustrates use
 * of the Javasoft "Project X" XML document interface.
 * To use this program, simply run it, then enter the URL
 * of an XML file in the text field at the top.
 */

public class XmlView2 extends Frame implements ActionListener {
    List contents;
    Label caption;
    TextField filename;
    Button goButton;
    TextArea status;

    // Names of types from org.w3c.dom.Node.
    public static final String [] typeNames = {
	"unknown",
	"element",
	"attr",
	"text",
	"CDATASection",
	"EntityReference",
	"Entity",
	"ProcessingInstruction",
	"Comment",
	"Document",
	"DocumentType",
	"DocumentFragment",
	"Notation",
    };	

    /**
     * Constructor - create the AWT interface.
     */
    public XmlView2() {
	super("XmlView2 - DOM");
	contents = new List();
	caption = new Label("XML Source URL:", Label.RIGHT);
	filename = new TextField();
	goButton = new Button("PARSE");
	Panel npanel = new Panel();
	npanel.setLayout(new BorderLayout(2,2));
	Panel topPanel = new Panel();
	topPanel.setLayout(new BorderLayout(2,0));
	topPanel.add("West",caption);
	topPanel.add("Center",filename);
	topPanel.add("East", goButton);
	npanel.add("North", topPanel);
	add("Center", contents);
	status = new TextArea(4,40);
	npanel.add("South", status);
	contents.setBackground(Color.white);
	add("North", npanel);
	setSize(490,620);
	setLocation(140,60);
	goButton.addActionListener(this);
	filename.addActionListener(this);
    }

    /**
     * Log a message to the scrolling text area.
     */
    private void logMessage(String s) {
	status.append(s);
	status.append("\n");
	try { Thread.sleep(40); } catch (InterruptedException ie) { }
    }

    /**
     * Prepend indentation onto the front of a string, return
     * result as a StringBuffer.
     */
    private StringBuffer indent(int depth, String t) {
	StringBuffer s = new StringBuffer(depth + t.length());
	for(int i = 0; i < depth; i++) s.append("    ");
	s.append(t);
	return s;
    }

    /**
     * Recursively dump an XmlDocument or other Node into
     * the AWT List contents.  
     * The parameter depth is the indentation amount, not
     * strictly the tree depth.
     */
    public void dumpXmlNode(Node n, int depth) {
	StringBuffer sb;
	NamedNodeMap attrs = n.getAttributes();
	if (n instanceof XmlDocument) {
	    sb = indent(depth, "Document Start (type=");
	    DocumentType dt = ((XmlDocument)n).getDoctype();
	    if (dt == null) sb.append("unknown");
	    else sb.append(dt.getName());
	    sb.append(")");
	    contents.add(sb.toString());
	}
	else {
	    sb = indent(depth, "Node: ");
	    sb.append(n.getNodeName());
	    sb.append(" (type=");
	    int typ = n.getNodeType();
	    if (typ >= 0 && typ < typeNames.length)
		sb.append(typeNames[typ] + ")");
	    else 
		sb.append(typ + ")");
	    sb.append(" (attrs=");
	    sb.append(((attrs==null)?(0):(attrs.getLength())) + ")");
	    String val = n.getNodeValue();
	    if (val != null) {
		sb.append(" - ");
		sb.append(val);
	    }
	    contents.add(sb.toString());
	}
	if (attrs != null && attrs.getLength() > 0) {
	    Node nc;
	    int d = depth + 3;
	    for(int i = 0; i < attrs.getLength(); i++) {
		nc = attrs.item(i);
		dumpXmlNode(nc, d);
	    }
	}
	if (n.hasChildNodes()) {
	    Node nc;
	    int d = depth + 1;
	    for(nc = n.getFirstChild(); nc != null; nc = nc.getNextSibling()) {
		dumpXmlNode(nc, d);
	    }
	}
    }

    /**
     * React to the user telling us to do the parsing.
     */
    boolean running = false;
    public synchronized void actionPerformed(ActionEvent e) {
	if (running) {
	    logMessage("Already busy, please wait...");
	    return;
	}
	String fn = filename.getText();
	ParThread pt = new ParThread(fn);
	running = true;
	pt.setPriority(Thread.NORM_PRIORITY - 1);
	pt.start();
    }

    /**
     * This thread class does all the actual parsing and
     * displaying.  Good thing AWT List is thread-safe!
     */
    class ParThread extends Thread {
	String fn;
	ParThread(String f) { fn = f; }

	/**
	 * Open the URL, parse the contents into a XmlDocument,
	 * then dump the document into the List.  Log lots of
	 * messages to the scrolling text area.
	 */
	public void run() {
	    URL u2 = null;
	    long stime = System.currentTimeMillis();
	    try {
		URL u1;
		File f = new File(".");
		u1 = new URL("file:" + f.getAbsolutePath());
		u2 = new URL(u1, fn);
	    }
	    catch (MalformedURLException mue) {
		logMessage("Bad URL: " + u2);
		synchronized (XmlView2.this) { running = false; }
		return;
	    }
	
	    logMessage("Clearing list..");
	    contents.removeAll();
	
	    XmlDocument doc = null;
	    try {
		logMessage("Creating document...");
		try {
		    doc = XmlDocument.createXmlDocument(u2.toString(), true);
		    logMessage("Parsing with validation succeeded!");
		} catch (SAXException sep) {
		    logMessage("Validating parse failed: " + sep);
		    logMessage("  --- trying non-validating.");
		    doc = null;
		}
		if (doc == null) {
		    doc = XmlDocument.createXmlDocument(u2.toString(), false);
		    logMessage("Parsing without validation succeeded.");
		}
		long etime = System.currentTimeMillis();
		logMessage("Parsing done, time = " + (etime - stime) + "ms.");
		logMessage("Dumping structure to List window...");
		dumpXmlNode(doc,0);
		logMessage("Total nodes in document: " + contents.getItemCount());
	    }
	    catch (Exception se) {
		logMessage("Parsing exception: " + se);
		contents.add("Parsing Exception Thrown!!!");
		// se.printStackTrace();
	    }
	    long ftime = System.currentTimeMillis();
	    logMessage("Done with " + u2.toString() + 
		       "\n     total time = " + (ftime - stime) + "ms.");
	    synchronized (XmlView2.this) { running = false; }
	}
    }

    /**
     * Main routine to kick off the program.  Simply creates the
     * XmlView2 object and shows it.
     */
    public static void main(String args[]) {
	XmlView2 v2 = new XmlView2();
	v2.addWindowListener(new WindowAdapter() {
	    public void windowClosing(WindowEvent e) {
		System.out.println("All done.  Bye.");
		System.exit(0);
	    }
	} );
	v2.show();
    }
}