/* ------------------------------------------------------------------------ File: SoarClient.java Synopsis: A simple client applet that talks to a remote Soar Created By: Christopher R. Waterson Created On: 05 Sep 1996 Modified By: Christopher R. Waterson Modified On: 11 Sep 1996 This file contains an applet that connects to a Soar7 server, pipes all of its input to a console window, and sends commmands to the server for execution. ------------------------------------------------------------------------ */ import java.applet.*; import java.awt.*; import java.io.*; import java.net.*; import java.util.*; /** * A simple applet that connects to a Soar7 server, sending it commands * and receiving its output via a socket. * * @author Christopher R. Waterson * @version 1.0.0 */ public class SoarClientApplet extends java.applet.Applet implements Runnable { /** * The default port on which to attempt to connect */ protected static final int DEFAULT_PORT = 1212; /** * The layout manager for the applet. */ GridBagLayout m_layoutManager; /** * The window where soar's output appears. */ TextArea m_output; /** * A field for entering commands into soar */ TextField m_input; /** * A button to send commands to soar */ Button m_send; /** * The socket to which we're connected to the Soar server */ Socket m_socket; /** * Initialize the applet: create controls, connect to Soar, * and start a thread to monitor Soar's responses. */ public void init() { // Create the controls to run the applet m_layoutManager = new GridBagLayout(); setLayout(m_layoutManager); m_output = new TextArea(); add(m_output, 0, 0, 2, 1, GridBagConstraints.BOTH, 1, 1); m_output.setFont(new Font("Courier", Font.PLAIN, 12) ); m_output.setEditable(false); m_input = new TextField(); add(m_input, 0, 1, 1, 1, GridBagConstraints.HORIZONTAL, 1, 0); m_send = new Button("Send"); add(m_send, 1, 1, 1, 1, GridBagConstraints.NONE, 0, 0); // Disable until the connection is alive. m_input.enable(false); m_send.enable(false); } /** * A helper to create components in the GridBagLayout */ protected void add(Component cmp, int gridx, int gridy, int gridwidth, int gridheight, int fill, int weightx, int weighty) { GridBagConstraints c = new GridBagConstraints(); c.gridx = gridx; c.gridy = gridy; c.gridwidth = gridwidth; c.gridheight = gridheight; c.fill = fill; c.anchor = GridBagConstraints.CENTER; c.weightx = weightx; c.weighty = weighty; m_layoutManager.setConstraints(cmp, c); add(cmp); } /** * Connect to the Soar server and enable the user * interface. */ public void start() { // Connect try { URL url = getDocumentBase(); int port = DEFAULT_PORT; String param = getParameter("Port"); if (param != null && param.length() > 0) port = Integer.parseInt(param); m_socket = new Socket(url.getHost(), port); } catch (java.io.IOException e) { m_output.setText("Unable to connect to Soar:\n" + e); e.printStackTrace(); return; } // Ok, if we get here, we're set! m_input.enable(true); m_send.enable(true); m_input.requestFocus(); // Start the input monitor thread. Thread inputMonitor = new Thread(this); inputMonitor.start(); } /** * Kill the server process by sending the "exit" command * to Soar. */ public void stop() { if (m_socket == null) return; try { sendString("exit\n"); m_socket.getOutputStream().flush(); m_socket.close(); } catch (java.io.IOException e) { // Not much else we can do now... e.printStackTrace(); } } /** * Handle user input events. */ public boolean action(Event event, Object target) { if (event.target == m_send) { sendCommand(m_input.getText()); m_input.setText(""); } return true; } /** * Handle user input events. Traps the "enter" key * to issue a send to soar. */ public boolean handleEvent(Event event) { if (event.id == Event.KEY_PRESS && event.target == m_input && event.key == 10) { // Enter sendCommand(m_input.getText()); m_input.setText(""); return true; } return super.handleEvent(event); } /** * Send the specified command string to soar. Adds additional * preamble and postamble to ensure that the command gets processed * and output gets sent back to us. * * @param command The command to send to soar. */ protected void sendCommand(String command) { try { //System.out.println("Sending \"" + command + "\""); // Print the command first sendString("puts \"" + command + "\"\n"); // ...then send it for real sendString(command + "\n"); // Add another carriage return sendString("puts \\n\n"); // ...and force stdout to flush sendString("flush stdout\n"); sendString("flush stderr\n"); // Now flush our *own* output m_socket.getOutputStream().flush(); } catch (java.io.IOException e) { e.printStackTrace(); } } /** * Send a single string to soar. * @param s The string to send to Soar. * @exception java.io.IOException If there is a problem sending * the output to Soar. */ protected void sendString(String s) throws java.io.IOException { byte[] buffer = new byte[s.length()]; for (int i = 0; i < s.length(); ++i) { buffer[i] = (byte) s.charAt(i); } m_socket.getOutputStream().write(buffer); } /** * Hand around in the background waiting for Soar to send us * output. When it does, display it in the output window. * Kinda inefficient, but there's no blocking I/O that I * could find. */ public void run() { try { byte[] buffer = new byte[1024]; for ( ; ; ) { int bytesRead = m_socket.getInputStream().read(buffer); if (bytesRead > 0) { String soarOutput = new String(buffer, 0, 0, bytesRead); m_output.appendText(soarOutput); } } } catch (java.io.IOException e) { // Display an error message to the user m_output.appendText("There was an error reading "); m_output.appendText("input from Soar:\n" + e); m_output.appendText("\nThe connection has been closed."); // Disable so they don't try to send more input m_send.enable(false); m_input.enable(false); // In case someone cares... e.printStackTrace(); } } }