import java.io.*;
import java.awt.*;
import java.awt.event.*;
import org.xml.sax.*;
import com.sun.xml.parser.*;
import org.xml.sax.helpers.*;

/**
 * XmlView1 - a small AWT GUI program that illustrates use
 * of the javasoft SAX implementation.  Note that this
 * little program cannot parse any XML file that specifies
 * a DTD, because SAX is very fussy about DTD URIs.
 * XmlView2 is more sophisticated, and can handle XML files
 * that have DTDs.
 */

public class XmlView1 extends Frame implements ActionListener {
    List contents;
    Label caption;
    TextField filename;
    Button goButton;

    /**
     * Constructor - create the AWT GUI
     */
    public XmlView1() {
	super("XmlView1");
	contents = new List();
	caption = new Label("XML file:");
	filename = new TextField();
	goButton = new Button("PARSE");
	Panel topPanel = new Panel();
	topPanel.setLayout(new BorderLayout(2,2));
	topPanel.add("West",caption);
	topPanel.add("Center",filename);
	topPanel.add("East", goButton);
	add("North", topPanel);
	add("Center", contents);
	setSize(400,500);
	goButton.addActionListener(this);
    }

    /**
     * This class is a SAX listener that accepts the parse
     * events during parsing.
     */
    public class ListingHandler extends HandlerBase {
	int depth = 0;
	int count = 0;

	private String indent(String t) {
	    StringBuffer s = new StringBuffer(depth + t.length());
	    for(int i = 0; i < depth; i++) s.append("    ");
	    s.append(t);
	    return s.toString();
	}
	public void characters(char [] ch, int start, int length) {
	    String s = indent("CHARS" + length + ": ");
	    s += new String(ch, start, length);
	    contents.add(s);
	}
	
	public void endDocument() {
	    depth -= 1;
	    String s = indent("EndDocument");
	    contents.add(s);
	}

	public void endElement(String name) {
	    depth -= 1;
	    String s = indent("EndElement: ");
	    s += name;
	    contents.add(s);
	}

	public void warning(SAXParseException e) {
	    depth -= 1;
	    String s = indent("Warning! ");
	    s += e.toString();
	    contents.add(s);
	}
	public void error(SAXParseException e) {
	    depth -= 1;
	    String s = indent("ERROR! ");
	    s += e.toString();
	    contents.add(s);
	}
	public void fatalError(SAXParseException e) {
	    depth = 0;
	    String s = indent("FATAL ERROR!!! ");
	    s += e.toString();
	    contents.add(s);
	}
	public void processingInstruction(String target, String data) {
	    String s = indent("ProcInstr: ");
	    s += target;
	    s += "/";
	    s += data;
	    contents.add(s);
	}
	public void startDocument() {
	    depth = 0;
	    String s = "StartDocument";
	    contents.add(s);
	    depth += 1;
	    count += 1;
	}
	public void startElement(String name, AttributeList alist) {
	    String s = indent("StartElement: ");
	    s += name;
	    contents.add(s);
	    depth += 3;
	    doAttributeList(alist);
	    depth -= 3;
	    depth += 1;
	    count += 1;
	}
	private void doAttributeList(AttributeList a) {
	    int i;
	    String s;
	    for(i = 0; i < a.getLength(); i++) {
		s = indent("Attribute: ");
		s += a.getName(i);
		s += "=";
		s += a.getValue(i);
		contents.add(s);
	    }
	}
	
    }

    /**
     * Start the parsing when the user tells us to do so.
     */
    public void actionPerformed(ActionEvent e) {
	String fn = filename.getText();
	FileInputStream fis;
	try {
	    fis = new FileInputStream(fn);
	}
	catch (IOException ex2) {
	    System.out.println("Bad file: " + fn);
	    return;
	}
	
	System.out.println("Creating InputSource...");
	InputSource is = new InputSource(fis);
	
	System.out.println("Creating and configuring Parser...");
	com.sun.xml.parser.Parser myparser = new com.sun.xml.parser.Parser();
	myparser.setFastStandalone(true);
	org.xml.sax.Parser p = myparser;
	ListingHandler lh = new ListingHandler();
	p.setDocumentHandler(lh);
	p.setErrorHandler(lh);
	
	System.out.println("Clearing list..");
	contents.removeAll();
	
	try {
	    System.out.println("Parsing..");
	    p.parse(is);
	    System.out.println("Done, " + lh.count + " elements parsed.");
	}
	catch (Exception se) {
	    System.out.println("Parsing exception: " + se);
	    contents.add("Parsing Exception Thrown!!!");
	}
	try { fis.close(); } catch (IOException e4) { }
    }

    /**
     * Main method - kick off the program.
     */
    public static void main(String args[]) {
	XmlView1 v1 = new XmlView1();
	v1.show();
	v1.addWindowListener(new WindowAdapter() {
	    public void windowClosing(WindowEvent e) {
		System.out.println("All done.  Bye.");
		System.exit(0);
	    }
	} );
    }
}