tachttpconnection.java

TAC 客户端 Tac agent 客户端 TAC 客户端 Tac agent 客户端

/**
 * TAC AgentWare
 * http://www.sics.se/tac        [e-mail]
 *
 * Copyright (c) 2001-2005 SICS AB. All rights reserved.
 *
 * SICS grants you the right to use, modify, and redistribute this
 * software for noncommercial purposes, on the conditions that you:
 * (1) retain the original headers, including the copyright notice and
 * this text, (2) clearly document the difference between any derived
 * software and the original, and (3) acknowledge your use of this
 * software in pertaining publications and reports.  SICS provides
 * this software "as is", without any warranty of any kind.  IN NO
 * EVENT SHALL SICS BE LIABLE FOR ANY DIRECT, SPECIAL OR INDIRECT,
 * PUNITIVE, INCIDENTAL OR CONSEQUENTIAL LOSSES OR DAMAGES ARISING OUT
 * OF THE USE OF THE SOFTWARE.
 *
 * -----------------------------------------------------------------
 *
 * Author  : Joakim Eriksson, Niclas Finne, Sverker Janson
 * Created : 23 April, 2002
 * Updated : $Date: 2005/06/07 19:06:16 $
 *	     $Revision: 1.1 $
 *
 * -------------------------------------
 *
 * TACHttpConnection
 * A connection class for connections to the server via HTTP
 */

package se.sics.tac.aw;
import java.io.*;
import java.net.*;
import java.util.ArrayList;
import java.util.logging.*;

public class TACHttpConnection extends TACConnection implements Runnable {

  private static final Logger log =
    Logger.getLogger(TACHttpConnection.class.getName());

  private URL url;
  private ArrayList queue = new ArrayList();
  private boolean disconnected = false;

  protected void init() {
    try {
      url = new URL("http://" + agent.getHost() + ':' + agent.getPort() +
		    '/' + agent.getUser() + '/' + agent.getPassword());
      log.fine("Using HTTP TAC server at " + url);
      new Thread(this).start();

      TACMessage msg = new TACMessage("auth");
      msg.setParameter("userName", agent.getUser());
      msg.setParameter("userPW", agent.getPassword());
      msg.setMessageReceiver(agent);
      sendMessage(msg);
    } catch (Exception e) {
      new RuntimeException("Fatal: " + e);
    }
  }

  public boolean isConnected() {
    return !disconnected;
  }

  public void disconnect() {
    disconnected = true;
  }

  public void run() {
    while (true) {
      TACMessage msg = getMessage();
      boolean sent;
      for (int errors = 0; !(sent = sendMsg(msg)) && errors < 3; errors++) {
	log.warning("failed to send message " + msg.getType()
		    + " (retry " + (errors + 1) + ')');
	try {
	  Thread.sleep(1000);
	} catch (Exception e) {
	  e.printStackTrace();
	}
      }
      if (!sent) {
	agent.fatalError("could not send message " + msg.getType()
			 + " to server");
      }
    }
  }

  private synchronized TACMessage getMessage() {
    while (queue.isEmpty()) {
      try {
	wait();
      } catch (Exception e) {
	e.printStackTrace();
      }
    }
    return (TACMessage) queue.remove(0);
  }

  private synchronized void addMessage(TACMessage msg) {
    queue.add(msg);
    notify();
  }

  public void sendMessage(TACMessage msg) throws IOException {
    if (disconnected) {
      throw new IOException("Disconnected from server");
    }
    addMessage(msg);
  }

  private boolean sendMsg(TACMessage msg) {
    try {
      String msgStr = msg.getMessageString();
      URLConnection conn = url.openConnection();
      conn.setRequestProperty("Content-Length", "" + msgStr.length());
      conn.setDoOutput(true);
      OutputStream output = conn.getOutputStream();
      output.write(msgStr.getBytes());
      output.flush();

      InputStream input = conn.getInputStream();
      int len = conn.getContentLength();
      int totalRead = 0;
      int read;
      byte[] content = new byte[len];
      while ((len > totalRead)
	     && (read = input.read(content, totalRead, len - totalRead)) > 0) {
	totalRead += read;
      }
      output.close();
      input.close();

      if (len < totalRead) {
	// Connection closed from other end
	log.severe("truncated message response for " + msg.getType());
	return false;

      } else {
	msgStr = new String(content);
	msg.setReceivedMessage(msgStr);

	// Should be delivered by a dispatcher!!!

	msg.deliverMessage();
      }
      return true;
    } catch (Exception e) {
      log.log(Level.SEVERE, "could not send message", e);
      return false;
    }
  }

} // TACHttpConnection