package sax;

import javax.xml.parsers.*;
import org.xml.sax.*;
import org.xml.sax.helpers.*;

import java.util.*;
import java.io.*;

public class SAXLocalNameCount extends DefaultHandler {

    Hashtable tags;

    static public void main(String[] args) throws Exception {
        String filename = null;

        for (int i = 0; i < args.length; i++) {
            filename = args[i];
            if (i != args.length - 1) {
                usage();
            }
        }

        if (filename == null) {
            usage();
        }

        SAXParserFactory spf = SAXParserFactory.newInstance();
        spf.setNamespaceAware(true);
        SAXParser saxParser = spf.newSAXParser();
        XMLReader xmlReader = saxParser.getXMLReader();
        xmlReader.setContentHandler(new SAXLocalNameCount());
        xmlReader.setErrorHandler(new MyErrorHandler(System.err));
        xmlReader.parse(convertToFileURL(filename));
    }

    public void startDocument() throws SAXException {
        tags = new Hashtable();
    }

    public void startElement(String namespaceURI,
            String localName,
            String qName,
            Attributes atts)
            throws SAXException {

        String key = localName;
        Object value = tags.get(key);

        if (value == null) {
            tags.put(key, new Integer(1));
        } else {
            int count = ((Integer) value).intValue();
            count++;
            tags.put(key, new Integer(count));
        }
    }

    public void endDocument() throws SAXException {
        Enumeration e = tags.keys();
        while (e.hasMoreElements()) {
            String tag = (String) e.nextElement();
            int count = ((Integer) tags.get(tag)).intValue();
            System.out.println("Local Name \"" + tag + "\" occurs "
                    + count + " times");
        }
    }

    private static String convertToFileURL(String filename) {
        String path = new File(filename).getAbsolutePath();
        if (File.separatorChar != '/') {
            path = path.replace(File.separatorChar, '/');
        }

        if (!path.startsWith("/")) {
            path = "/" + path;
        }
        return "file:" + path;
    }

    private static void usage() {
        System.err.println("Usage: SAXLocalNameCount <file.xml>");
        System.err.println("       -usage or -help = this message");
        System.exit(1);
    }

    private static class MyErrorHandler implements ErrorHandler {

        private PrintStream out;

        MyErrorHandler(PrintStream out) {
            this.out = out;
        }

        private String getParseExceptionInfo(SAXParseException spe) {
            String systemId = spe.getSystemId();

            if (systemId == null) {
                systemId = "null";
            }

            String info = "URI=" + systemId + " Line="
                    + spe.getLineNumber() + ": " + spe.getMessage();

            return info;
        }

        public void warning(SAXParseException spe) throws SAXException {
            out.println("Warning: " + getParseExceptionInfo(spe));
        }

        public void error(SAXParseException spe) throws SAXException {
            String message = "Error: " + getParseExceptionInfo(spe);
            throw new SAXException(message);
        }

        public void fatalError(SAXParseException spe) throws SAXException {
            String message = "Fatal Error: " + getParseExceptionInfo(spe);
            throw new SAXException(message);
        }
    }
}