package dcj.examples.messageV2;

import java.lang.*;
import java.io.*;
import java.net.*;


abstract class BasicMsgHandler implements Runnable {
  InputStream msgIn;
  OutputStream msgOut;
  StreamTokenizer tokenizer;
  String msgEndToken;
  String tokenDelim;
  static BasicMsgHandler current = null;

  public BasicMsgHandler(InputStream in, OutputStream out,
                         String endToken,
                         String delim) {
    msgEndToken = endToken;
    tokenDelim = delim;
    setStreams(in, out);
  }

  protected void setStreams(InputStream in, OutputStream out) {
    msgIn = in;
    msgOut = out;

    // Wrap the input stream with a tokenizer
    tokenizer = new StreamTokenizer(msgIn);

    // Set the token delimiting characters on the tokenizer
    int len = tokenDelim.length();
    for (int i = 0; i < len; i++)
      tokenizer.whitespaceChars(tokenDelim.charAt(i), tokenDelim.charAt(i));
  }

  public BasicMessage readMsg() throws IOException {
    BasicMessage msg;

    if (tokenizer.nextToken() == StreamTokenizer.TT_WORD) {
      String msgId = tokenizer.sval;
      msg = buildMessage(msgId);
      if (msg.readArgs(msgIn)) {
        return msg;
      }
      else {
        msg = null;
      }
    }
    else {
      return null;
    }
    return msg;
  }

  public void sendMsg(BasicMessage msg) throws IOException {
    boolean success = true;
    DataOutputStream dout = new DataOutputStream(msgOut);

    char delim = tokenDelim.charAt(0);
    dout.writeUTF(msg.messageID());
    msg.writeArgs(msgOut);
  }

  public void run() {
    try {
      while (true) {
        BasicMessage msg = readMsg();
        msg.Do();
      }
    }
    // Treat an IOException as a termination of the message
    // exchange, and let this message-processing thread die.
    catch (IOException e) {}
  }

  protected abstract BasicMessage buildMessage(String msgId);
}