src/edu/berkeley/sbp/misc/ParserServlet.java

   1 package edu.berkeley.sbp.misc;
   2 import edu.berkeley.sbp.util.*;
   3 import edu.berkeley.sbp.*;
   4 import edu.berkeley.sbp.chr.*;
   5 import java.util.*;
   6 import java.io.*;
   7 import javax.servlet.*;
   8 import javax.servlet.http.*;
   9 import java.io.*;
  10 import java.net.*;
  11 import java.util.*;
  12
  13 public class ParserServlet extends HttpServlet {
  14
  15     public void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException {
  16         doPost(req, resp);
  17     }
  18     public void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException {
  19         try {
  20         try {
  21             System.out.println("a");
  22
  23             Tree<String> gram =
  24                 new CharParser(MetaGrammar.make()).parse(new StringReader(req.getParameter("grammar").trim())).expand1();
  25             System.out.println("b");
  26             Union meta = MetaGrammar.make();
  27             Forest<String> out = new CharParser(meta).parse(new StringReader(req.getParameter("input").trim()));
  28             System.out.println(out);
  29
  30             final GraphViz gv = new GraphViz();
  31             out.toGraphViz(gv);
  32
  33             resp.setContentType("image/svg+xml");
  34             final Process proc = Runtime.getRuntime().exec(new String[] { "dot", "-Tsvg" });
  35             new Thread() {
  36                 public void run() {
  37                     try {
  38                         PrintWriter pw = new PrintWriter(new OutputStreamWriter(proc.getOutputStream()));
  39                         gv.dump(pw);
  40                         pw.flush();
  41                         pw.close();
  42                     } catch (Exception e) {
  43                         e.printStackTrace();
  44                    }
  45                 }
  46             }.start();
  47
  48             byte[] buf = new byte[1024];
  49             InputStream is = proc.getInputStream();
  50             OutputStream os = resp.getOutputStream();
  51
  52             while(true) {
  53                 int numread = is.read(buf, 0, buf.length);
  54                 if (numread==-1) break;
  55                 os.write(buf, 0, numread);
  56             }
  57             os.flush();
  58             os.close();
  59
  60         } catch (ParseFailed e) {
  61             e.printStackTrace();
  62             resp.setContentType("text/plain");
  63             PrintWriter pw = new PrintWriter(new OutputStreamWriter(resp.getOutputStream()));
  64             pw.println(e);
  65             pw.flush();
  66             pw.close();
  67         }
  68
  69         } catch (Exception e) {
  70             throw new ServletException(e);
  71         }
  72     }
  73
  74 }