import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;

public class Counter extends HttpServlet{
	
	File file = null;
	
	//Skapar filen count och skriver vŠrdet 0 om den inte redan finns
	public void init() throws ServletException{
		try{
			file = new File(getServletContext().getRealPath("count"));
			if (file.createNewFile())
				writeValue(file, 0);
		}catch (IOException ignore){}
	}

	public void destroy(){
		super.destroy();
	}

	//Returnerar vŠrdet frŚn filen count
	int readValue(File file)throws IOException{
		BufferedReader infile = new BufferedReader(new FileReader(file));
		int tmp = Integer.parseInt(infile.readLine());
		infile.close();
		return tmp;
	}

	//Skriver ett nytt vŠrde till filen count
	void writeValue(File file, int value)throws IOException{
		PrintWriter outfile = new PrintWriter(new FileWriter(file));
		outfile.println(value);
		outfile.close();
	}

	//…kar vŠrdet pŚ filen count och skriver ut det nya vŠrdet i plain text
	public void doGet(HttpServletRequest req, HttpServletResponse res)throws ServletException, IOException {
		int count = 0;
		res.setContentType("text/plain");
		PrintWriter out = res.getWriter();
		synchronized (this){
			count = readValue(file);
			writeValue(file, ++count);
		}
		out.println(count);
	}
}