WebSocketClient.java

/*
 * Copyright (c) 2010-2020 Nathan Rajlich
 *
 *  Permission is hereby granted, free of charge, to any person
 *  obtaining a copy of this software and associated documentation
 *  files (the "Software"), to deal in the Software without
 *  restriction, including without limitation the rights to use,
 *  copy, modify, merge, publish, distribute, sublicense, and/or sell
 *  copies of the Software, and to permit persons to whom the
 *  Software is furnished to do so, subject to the following
 *  conditions:
 *
 *  The above copyright notice and this permission notice shall be
 *  included in all copies or substantial portions of the Software.
 *
 *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 *  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
 *  OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 *  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
 *  HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
 *  WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 *  FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 *  OTHER DEALINGS IN THE SOFTWARE.
 */

package org.java_websocket.client;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.lang.reflect.InvocationTargetException;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.Proxy;
import java.net.Socket;
import java.net.URI;
import java.net.UnknownHostException;
import java.nio.ByteBuffer;
import java.security.KeyManagementException;
import java.security.NoSuchAlgorithmException;
import java.util.Collection;
import java.util.Collections;
import java.util.Map;
import java.util.TreeMap;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;
import javax.net.SocketFactory;
import javax.net.ssl.SSLContext;
import javax.net.ssl.SSLException;
import javax.net.ssl.SSLParameters;
import javax.net.ssl.SSLSession;
import javax.net.ssl.SSLSocket;
import javax.net.ssl.SSLSocketFactory;
import org.java_websocket.AbstractWebSocket;
import org.java_websocket.WebSocket;
import org.java_websocket.WebSocketImpl;
import org.java_websocket.drafts.Draft;
import org.java_websocket.drafts.Draft_6455;
import org.java_websocket.enums.Opcode;
import org.java_websocket.enums.ReadyState;
import org.java_websocket.exceptions.InvalidHandshakeException;
import org.java_websocket.framing.CloseFrame;
import org.java_websocket.framing.Framedata;
import org.java_websocket.handshake.HandshakeImpl1Client;
import org.java_websocket.handshake.Handshakedata;
import org.java_websocket.handshake.ServerHandshake;
import org.java_websocket.protocols.IProtocol;

/**
 * A subclass must implement at least <var>onOpen</var>, <var>onClose</var>, and
 * <var>onMessage</var> to be useful. At runtime the user is expected to establish a connection via
 * {@link #connect()}, then receive events like {@link #onMessage(String)} via the overloaded
 * methods and to {@link #send(String)} data to the server.
 */
public abstract class WebSocketClient extends AbstractWebSocket implements Runnable, WebSocket {

  /**
   * The URI this channel is supposed to connect to.
   */
  protected URI uri = null;

  /**
   * The underlying engine
   */
  private WebSocketImpl engine = null;

  /**
   * The socket for this WebSocketClient
   */
  private Socket socket = null;

  /**
   * The SocketFactory for this WebSocketClient
   *
   * @since 1.4.0
   */
  private SocketFactory socketFactory = null;

  /**
   * The used OutputStream
   */
  private OutputStream ostream;

  /**
   * The used proxy, if any
   */
  private Proxy proxy = Proxy.NO_PROXY;

  /**
   * The thread to write outgoing message
   */
  private Thread writeThread;

  /**
   * The thread to connect and read message
   */
  private Thread connectReadThread;

  /**
   * The draft to use
   */
  private Draft draft;

  /**
   * The additional headers to use
   */
  private Map<String, String> headers;

  /**
   * The latch for connectBlocking()
   */
  private CountDownLatch connectLatch = new CountDownLatch(1);

  /**
   * The latch for closeBlocking()
   */
  private CountDownLatch closeLatch = new CountDownLatch(1);

  /**
   * The socket timeout value to be used in milliseconds.
   */
  private int connectTimeout = 0;

  /**
   * DNS resolver that translates a URI to an InetAddress
   *
   * @see InetAddress
   * @since 1.4.1
   */
  private DnsResolver dnsResolver = null;

  /**
   * Constructs a WebSocketClient instance and sets it to the connect to the specified URI. The
   * channel does not attampt to connect automatically. The connection will be established once you
   * call <var>connect</var>.
   *
   * @param serverUri the server URI to connect to
   */
  public WebSocketClient(URI serverUri) {
    this(serverUri, new Draft_6455());
  }

  /**
   * Constructs a WebSocketClient instance and sets it to the connect to the specified URI. The
   * channel does not attampt to connect automatically. The connection will be established once you
   * call <var>connect</var>.
   *
   * @param serverUri     the server URI to connect to
   * @param protocolDraft The draft which should be used for this connection
   */
  public WebSocketClient(URI serverUri, Draft protocolDraft) {
    this(serverUri, protocolDraft, null, 0);
  }

  /**
   * Constructs a WebSocketClient instance and sets it to the connect to the specified URI. The
   * channel does not attampt to connect automatically. The connection will be established once you
   * call <var>connect</var>.
   *
   * @param serverUri   the server URI to connect to
   * @param httpHeaders Additional HTTP-Headers
   * @since 1.3.8
   */
  public WebSocketClient(URI serverUri, Map<String, String> httpHeaders) {
    this(serverUri, new Draft_6455(), httpHeaders);
  }

  /**
   * Constructs a WebSocketClient instance and sets it to the connect to the specified URI. The
   * channel does not attampt to connect automatically. The connection will be established once you
   * call <var>connect</var>.
   *
   * @param serverUri     the server URI to connect to
   * @param protocolDraft The draft which should be used for this connection
   * @param httpHeaders   Additional HTTP-Headers
   * @since 1.3.8
   */
  public WebSocketClient(URI serverUri, Draft protocolDraft, Map<String, String> httpHeaders) {
    this(serverUri, protocolDraft, httpHeaders, 0);
  }

  /**
   * Constructs a WebSocketClient instance and sets it to the connect to the specified URI. The
   * channel does not attampt to connect automatically. The connection will be established once you
   * call <var>connect</var>.
   *
   * @param serverUri      the server URI to connect to
   * @param protocolDraft  The draft which should be used for this connection
   * @param httpHeaders    Additional HTTP-Headers
   * @param connectTimeout The Timeout for the connection
   */
  public WebSocketClient(URI serverUri, Draft protocolDraft, Map<String, String> httpHeaders,
      int connectTimeout) {
    if (serverUri == null) {
      throw new IllegalArgumentException();
    } else if (protocolDraft == null) {
      throw new IllegalArgumentException("null as draft is permitted for `WebSocketServer` only!");
    }
    this.uri = serverUri;
    this.draft = protocolDraft;
    this.dnsResolver = new DnsResolver() {
      @Override
      public InetAddress resolve(URI uri) throws UnknownHostException {
        return InetAddress.getByName(uri.getHost());
      }
    };
    if (httpHeaders != null) {
      headers = new TreeMap<>(String.CASE_INSENSITIVE_ORDER);
      headers.putAll(httpHeaders);
    }
    this.connectTimeout = connectTimeout;
    setTcpNoDelay(false);
    setReuseAddr(false);
    this.engine = new WebSocketImpl(this, protocolDraft);
  }

  /**
   * Returns the URI that this WebSocketClient is connected to.
   *
   * @return the URI connected to
   */
  public URI getURI() {
    return uri;
  }

  /**
   * Returns the protocol version this channel uses.<br> For more infos see
   * https://github.com/TooTallNate/Java-WebSocket/wiki/Drafts
   *
   * @return The draft used for this client
   */
  public Draft getDraft() {
    return draft;
  }

  /**
   * Returns the socket to allow Hostname Verification
   *
   * @return the socket used for this connection
   */
  public Socket getSocket() {
    return socket;
  }

  /**
   * @param key   Name of the header to add.
   * @param value Value of the header to add.
   * @since 1.4.1 Adds an additional header to be sent in the handshake.<br> If the connection is
   * already made, adding headers has no effect, unless reconnect is called, which then a new
   * handshake is sent.<br> If a header with the same key already exists, it is overridden.
   */
  public void addHeader(String key, String value) {
    if (headers == null) {
      headers = new TreeMap<>(String.CASE_INSENSITIVE_ORDER);
    }
    headers.put(key, value);
  }

  /**
   * @param key Name of the header to remove.
   * @return the previous value associated with key, or null if there was no mapping for key.
   * @since 1.4.1 Removes a header from the handshake to be sent, if header key exists.<br>
   */
  public String removeHeader(String key) {
    if (headers == null) {
      return null;
    }
    return headers.remove(key);
  }

  /**
   * @since 1.4.1 Clears all previously put headers.
   */
  public void clearHeaders() {
    headers = null;
  }

  /**
   * Sets a custom DNS resolver.
   *
   * @param dnsResolver The DnsResolver to use.
   * @since 1.4.1
   */
  public void setDnsResolver(DnsResolver dnsResolver) {
    this.dnsResolver = dnsResolver;
  }

  /**
   * Reinitiates the websocket connection. This method does not block.
   *
   * @since 1.3.8
   */
  public void reconnect() {
    reset();
    connect();
  }

  /**
   * Same as <code>reconnect</code> but blocks until the websocket reconnected or failed to do
   * so.<br>
   *
   * @return Returns whether it succeeded or not.
   * @throws InterruptedException Thrown when the threads get interrupted
   * @since 1.3.8
   */
  public boolean reconnectBlocking() throws InterruptedException {
    reset();
    return connectBlocking();
  }

  /**
   * Reset everything relevant to allow a reconnect
   *
   * @since 1.3.8
   */
  private void reset() {
    Thread current = Thread.currentThread();
    if (current == writeThread || current == connectReadThread) {
      throw new IllegalStateException(
          "You cannot initialize a reconnect out of the websocket thread. Use reconnect in another thread to ensure a successful cleanup.");
    }
    try {
      closeBlocking();
      if (writeThread != null) {
        this.writeThread.interrupt();
        this.writeThread = null;
      }
      if (connectReadThread != null) {
        this.connectReadThread.interrupt();
        this.connectReadThread = null;
      }
      this.draft.reset();
      if (this.socket != null) {
        this.socket.close();
        this.socket = null;
      }
    } catch (Exception e) {
      onError(e);
      engine.closeConnection(CloseFrame.ABNORMAL_CLOSE, e.getMessage());
      return;
    }
    connectLatch = new CountDownLatch(1);
    closeLatch = new CountDownLatch(1);
    this.engine = new WebSocketImpl(this, this.draft);
  }

  /**
   * Initiates the websocket connection. This method does not block.
   */
  public void connect() {
    if (connectReadThread != null) {
      throw new IllegalStateException("WebSocketClient objects are not reuseable");
    }
    connectReadThread = new Thread(this);
    connectReadThread.setName("WebSocketConnectReadThread-" + connectReadThread.getId());
    connectReadThread.start();
  }

  /**
   * Same as <code>connect</code> but blocks until the websocket connected or failed to do so.<br>
   *
   * @return Returns whether it succeeded or not.
   * @throws InterruptedException Thrown when the threads get interrupted
   */
  public boolean connectBlocking() throws InterruptedException {
    connect();
    connectLatch.await();
    return engine.isOpen();
  }

  /**
   * Same as <code>connect</code> but blocks with a timeout until the websocket connected or failed
   * to do so.<br>
   *
   * @param timeout  The connect timeout
   * @param timeUnit The timeout time unit
   * @return Returns whether it succeeded or not.
   * @throws InterruptedException Thrown when the threads get interrupted
   */
  public boolean connectBlocking(long timeout, TimeUnit timeUnit) throws InterruptedException {
    connect();
    return connectLatch.await(timeout, timeUnit) && engine.isOpen();
  }

  /**
   * Initiates the websocket close handshake. This method does not block<br> In oder to make sure
   * the connection is closed use <code>closeBlocking</code>
   */
  public void close() {
    if (writeThread != null) {
      engine.close(CloseFrame.NORMAL);
    }
  }

  /**
   * Same as <code>close</code> but blocks until the websocket closed or failed to do so.<br>
   *
   * @throws InterruptedException Thrown when the threads get interrupted
   */
  public void closeBlocking() throws InterruptedException {
    close();
    closeLatch.await();
  }

  /**
   * Sends <var>text</var> to the connected websocket server.
   *
   * @param text The string which will be transmitted.
   */
  public void send(String text) {
    engine.send(text);
  }

  /**
   * Sends binary <var> data</var> to the connected webSocket server.
   *
   * @param data The byte-Array of data to send to the WebSocket server.
   */
  public void send(byte[] data) {
    engine.send(data);
  }

  @Override
  public <T> T getAttachment() {
    return engine.getAttachment();
  }

  @Override
  public <T> void setAttachment(T attachment) {
    engine.setAttachment(attachment);
  }

  @Override
  protected Collection<WebSocket> getConnections() {
    return Collections.singletonList((WebSocket) engine);
  }

  @Override
  public void sendPing() {
    engine.sendPing();
  }

  public void run() {
    InputStream istream;
    try {
      boolean upgradeSocketToSSLSocket = prepareSocket();

      socket.setTcpNoDelay(isTcpNoDelay());
      socket.setReuseAddress(isReuseAddr());

      if (!socket.isConnected()) {
        InetSocketAddress addr = new InetSocketAddress(dnsResolver.resolve(uri), this.getPort());
        socket.connect(addr, connectTimeout);
      }

      // if the socket is set by others we don't apply any TLS wrapper
      if (upgradeSocketToSSLSocket && "wss".equals(uri.getScheme())) {
        upgradeSocketToSSL();
      }

      if (socket instanceof SSLSocket) {
        SSLSocket sslSocket = (SSLSocket) socket;
        SSLParameters sslParameters = sslSocket.getSSLParameters();
        onSetSSLParameters(sslParameters);
        sslSocket.setSSLParameters(sslParameters);
      }

      istream = socket.getInputStream();
      ostream = socket.getOutputStream();

      sendHandshake();
    } catch (/*IOException | SecurityException | UnresolvedAddressException | InvalidHandshakeException | ClosedByInterruptException | SocketTimeoutException */Exception e) {
      onWebsocketError(engine, e);
      engine.closeConnection(CloseFrame.NEVER_CONNECTED, e.getMessage());
      return;
    } catch (InternalError e) {
      // https://bugs.openjdk.java.net/browse/JDK-8173620
      if (e.getCause() instanceof InvocationTargetException && e.getCause()
          .getCause() instanceof IOException) {
        IOException cause = (IOException) e.getCause().getCause();
        onWebsocketError(engine, cause);
        engine.closeConnection(CloseFrame.NEVER_CONNECTED, cause.getMessage());
        return;
      }
      throw e;
    }

    writeThread = new Thread(new WebsocketWriteThread(this));
    writeThread.start();

    byte[] rawbuffer = new byte[WebSocketImpl.RCVBUF];
    int readBytes;

    try {
      while (!isClosing() && !isClosed() && (readBytes = istream.read(rawbuffer)) != -1) {
        engine.decode(ByteBuffer.wrap(rawbuffer, 0, readBytes));
      }
      engine.eot();
    } catch (IOException e) {
      handleIOException(e);
    } catch (RuntimeException e) {
      // this catch case covers internal errors only and indicates a bug in this websocket implementation
      onError(e);
      engine.closeConnection(CloseFrame.ABNORMAL_CLOSE, e.getMessage());
    }
    connectReadThread = null;
  }

  private void upgradeSocketToSSL()
      throws NoSuchAlgorithmException, KeyManagementException, IOException {
    SSLSocketFactory factory;
    // Prioritise the provided socketfactory
    // Helps when using web debuggers like Fiddler Classic
    if (socketFactory instanceof SSLSocketFactory) {
      factory = (SSLSocketFactory) socketFactory;
    } else {
      SSLContext sslContext = SSLContext.getInstance("TLSv1.2");
      sslContext.init(null, null, null);
      factory = sslContext.getSocketFactory();
    }
    socket = factory.createSocket(socket, uri.getHost(), getPort(), true);
  }

  private boolean prepareSocket() throws IOException {
    boolean upgradeSocketToSSLSocket = false;
    // Prioritise a proxy over a socket factory and apply the socketfactory later
    if (proxy != Proxy.NO_PROXY) {
      socket = new Socket(proxy);
      upgradeSocketToSSLSocket = true;
    } else if (socketFactory != null) {
      socket = socketFactory.createSocket();
    } else if (socket == null) {
      socket = new Socket(proxy);
      upgradeSocketToSSLSocket = true;
    } else if (socket.isClosed()) {
      throw new IOException();
    }
    return upgradeSocketToSSLSocket;
  }

  /**
   * Apply specific SSLParameters If you override this method make sure to always call
   * super.onSetSSLParameters() to ensure the hostname validation is active
   *
   * @param sslParameters the SSLParameters which will be used for the SSLSocket
   */
  protected void onSetSSLParameters(SSLParameters sslParameters) {
    // If you run into problem on Android (NoSuchMethodException), check out the wiki https://github.com/TooTallNate/Java-WebSocket/wiki/No-such-method-error-setEndpointIdentificationAlgorithm
    // Perform hostname validation
    sslParameters.setEndpointIdentificationAlgorithm("HTTPS");
  }

  /**
   * Extract the specified port
   *
   * @return the specified port or the default port for the specific scheme
   */
  private int getPort() {
    int port = uri.getPort();
    String scheme = uri.getScheme();
    if ("wss".equals(scheme)) {
      return port == -1 ? WebSocketImpl.DEFAULT_WSS_PORT : port;
    } else if ("ws".equals(scheme)) {
      return port == -1 ? WebSocketImpl.DEFAULT_PORT : port;
    } else {
      throw new IllegalArgumentException("unknown scheme: " + scheme);
    }
  }

  /**
   * Create and send the handshake to the other endpoint
   *
   * @throws InvalidHandshakeException a invalid handshake was created
   */
  private void sendHandshake() throws InvalidHandshakeException {
    String path;
    String part1 = uri.getRawPath();
    String part2 = uri.getRawQuery();
    if (part1 == null || part1.length() == 0) {
      path = "/";
    } else {
      path = part1;
    }
    if (part2 != null) {
      path += '?' + part2;
    }
    int port = getPort();
    String host = uri.getHost() + (
        (port != WebSocketImpl.DEFAULT_PORT && port != WebSocketImpl.DEFAULT_WSS_PORT)
            ? ":" + port
            : "");

    HandshakeImpl1Client handshake = new HandshakeImpl1Client();
    handshake.setResourceDescriptor(path);
    handshake.put("Host", host);
    if (headers != null) {
      for (Map.Entry<String, String> kv : headers.entrySet()) {
        handshake.put(kv.getKey(), kv.getValue());
      }
    }
    engine.startHandshake(handshake);
  }

  /**
   * This represents the state of the connection.
   */
  public ReadyState getReadyState() {
    return engine.getReadyState();
  }

  /**
   * Calls subclass' implementation of <var>onMessage</var>.
   */
  @Override
  public final void onWebsocketMessage(WebSocket conn, String message) {
    onMessage(message);
  }

  @Override
  public final void onWebsocketMessage(WebSocket conn, ByteBuffer blob) {
    onMessage(blob);
  }

  /**
   * Calls subclass' implementation of <var>onOpen</var>.
   */
  @Override
  public final void onWebsocketOpen(WebSocket conn, Handshakedata handshake) {
    startConnectionLostTimer();
    onOpen((ServerHandshake) handshake);
    connectLatch.countDown();
  }

  /**
   * Calls subclass' implementation of <var>onClose</var>.
   */
  @Override
  public final void onWebsocketClose(WebSocket conn, int code, String reason, boolean remote) {
    stopConnectionLostTimer();
    if (writeThread != null) {
      writeThread.interrupt();
    }
    onClose(code, reason, remote);
    connectLatch.countDown();
    closeLatch.countDown();
  }

  /**
   * Calls subclass' implementation of <var>onIOError</var>.
   */
  @Override
  public final void onWebsocketError(WebSocket conn, Exception ex) {
    onError(ex);
  }

  @Override
  public final void onWriteDemand(WebSocket conn) {
    // nothing to do
  }

  @Override
  public void onWebsocketCloseInitiated(WebSocket conn, int code, String reason) {
    onCloseInitiated(code, reason);
  }

  @Override
  public void onWebsocketClosing(WebSocket conn, int code, String reason, boolean remote) {
    onClosing(code, reason, remote);
  }

  /**
   * Send when this peer sends a close handshake
   *
   * @param code   The codes can be looked up here: {@link CloseFrame}
   * @param reason Additional information string
   */
  public void onCloseInitiated(int code, String reason) {
    //To overwrite
  }

  /**
   * Called as soon as no further frames are accepted
   *
   * @param code   The codes can be looked up here: {@link CloseFrame}
   * @param reason Additional information string
   * @param remote Returns whether or not the closing of the connection was initiated by the remote
   *               host.
   */
  public void onClosing(int code, String reason, boolean remote) {
    //To overwrite
  }

  /**
   * Getter for the engine
   *
   * @return the engine
   */
  public WebSocket getConnection() {
    return engine;
  }

  @Override
  public InetSocketAddress getLocalSocketAddress(WebSocket conn) {
    if (socket != null) {
      return (InetSocketAddress) socket.getLocalSocketAddress();
    }
    return null;
  }

  @Override
  public InetSocketAddress getRemoteSocketAddress(WebSocket conn) {
    if (socket != null) {
      return (InetSocketAddress) socket.getRemoteSocketAddress();
    }
    return null;
  }

  // ABSTRACT METHODS /////////////////////////////////////////////////////////

  /**
   * Called after an opening handshake has been performed and the given websocket is ready to be
   * written on.
   *
   * @param handshakedata The handshake of the websocket instance
   */
  public abstract void onOpen(ServerHandshake handshakedata);

  /**
   * Callback for string messages received from the remote host
   *
   * @param message The UTF-8 decoded message that was received.
   * @see #onMessage(ByteBuffer)
   **/
  public abstract void onMessage(String message);

  /**
   * Called after the websocket connection has been closed.
   *
   * @param code   The codes can be looked up here: {@link CloseFrame}
   * @param reason Additional information string
   * @param remote Returns whether or not the closing of the connection was initiated by the remote
   *               host.
   **/
  public abstract void onClose(int code, String reason, boolean remote);

  /**
   * Called when errors occurs. If an error causes the websocket connection to fail {@link
   * #onClose(int, String, boolean)} will be called additionally.<br> This method will be called
   * primarily because of IO or protocol errors.<br> If the given exception is an RuntimeException
   * that probably means that you encountered a bug.<br>
   *
   * @param ex The exception causing this error
   **/
  public abstract void onError(Exception ex);

  /**
   * Callback for binary messages received from the remote host
   *
   * @param bytes The binary message that was received.
   * @see #onMessage(String)
   **/
  public void onMessage(ByteBuffer bytes) {
    //To overwrite
  }


  private class WebsocketWriteThread implements Runnable {

    private final WebSocketClient webSocketClient;

    WebsocketWriteThread(WebSocketClient webSocketClient) {
      this.webSocketClient = webSocketClient;
    }

    @Override
    public void run() {
      Thread.currentThread().setName("WebSocketWriteThread-" + Thread.currentThread().getId());
      try {
        runWriteData();
      } catch (IOException e) {
        handleIOException(e);
      } finally {
        closeSocket();
        writeThread = null;
      }
    }

    /**
     * Write the data into the outstream
     *
     * @throws IOException if write or flush did not work
     */
    private void runWriteData() throws IOException {
      try {
        while (!Thread.interrupted()) {
          ByteBuffer buffer = engine.outQueue.take();
          ostream.write(buffer.array(), 0, buffer.limit());
          ostream.flush();
        }
      } catch (InterruptedException e) {
        for (ByteBuffer buffer : engine.outQueue) {
          ostream.write(buffer.array(), 0, buffer.limit());
          ostream.flush();
        }
        Thread.currentThread().interrupt();
      }
    }

    /**
     * Closing the socket
     */
    private void closeSocket() {
      try {
        if (socket != null) {
          socket.close();
        }
      } catch (IOException ex) {
        onWebsocketError(webSocketClient, ex);
      }
    }
  }


  /**
   * Method to set a proxy for this connection
   *
   * @param proxy the proxy to use for this websocket client
   */
  public void setProxy(Proxy proxy) {
    if (proxy == null) {
      throw new IllegalArgumentException();
    }
    this.proxy = proxy;
  }

  /**
   * Accepts bound and unbound sockets.<br> This method must be called before <code>connect</code>.
   * If the given socket is not yet bound it will be bound to the uri specified in the constructor.
   *
   * @param socket The socket which should be used for the connection
   * @deprecated use setSocketFactory
   */
  @Deprecated
  public void setSocket(Socket socket) {
    if (this.socket != null) {
      throw new IllegalStateException("socket has already been set");
    }
    this.socket = socket;
  }

  /**
   * Accepts a SocketFactory.<br> This method must be called before <code>connect</code>. The socket
   * will be bound to the uri specified in the constructor.
   *
   * @param socketFactory The socket factory which should be used for the connection.
   */
  public void setSocketFactory(SocketFactory socketFactory) {
    this.socketFactory = socketFactory;
  }

  @Override
  public void sendFragmentedFrame(Opcode op, ByteBuffer buffer, boolean fin) {
    engine.sendFragmentedFrame(op, buffer, fin);
  }

  @Override
  public boolean isOpen() {
    return engine.isOpen();
  }

  @Override
  public boolean isFlushAndClose() {
    return engine.isFlushAndClose();
  }

  @Override
  public boolean isClosed() {
    return engine.isClosed();
  }

  @Override
  public boolean isClosing() {
    return engine.isClosing();
  }

  @Override
  public boolean hasBufferedData() {
    return engine.hasBufferedData();
  }

  @Override
  public void close(int code) {
    engine.close(code);
  }

  @Override
  public void close(int code, String message) {
    engine.close(code, message);
  }

  @Override
  public void closeConnection(int code, String message) {
    engine.closeConnection(code, message);
  }

  @Override
  public void send(ByteBuffer bytes) {
    engine.send(bytes);
  }

  @Override
  public void sendFrame(Framedata framedata) {
    engine.sendFrame(framedata);
  }

  @Override
  public void sendFrame(Collection<Framedata> frames) {
    engine.sendFrame(frames);
  }

  @Override
  public InetSocketAddress getLocalSocketAddress() {
    return engine.getLocalSocketAddress();
  }

  @Override
  public InetSocketAddress getRemoteSocketAddress() {
    return engine.getRemoteSocketAddress();
  }

  @Override
  public String getResourceDescriptor() {
    return uri.getPath();
  }

  @Override
  public boolean hasSSLSupport() {
    return socket instanceof SSLSocket;
  }

  @Override
  public SSLSession getSSLSession() {
    if (!hasSSLSupport()) {
      throw new IllegalArgumentException(
          "This websocket uses ws instead of wss. No SSLSession available.");
    }
    return ((SSLSocket)socket).getSession();
  }

  @Override
  public IProtocol getProtocol() {
    return engine.getProtocol();
  }

  /**
   * Method to give some additional info for specific IOExceptions
   *
   * @param e the IOException causing a eot.
   */
  private void handleIOException(IOException e) {
    if (e instanceof SSLException) {
      onError(e);
    }
    engine.eot();
  }
}