/**
   * Sets the <tt>RTPConnector</tt> which is to use or uses this <tt>PacketTransformer</tt>.
   *
   * @param connector the <tt>RTPConnector</tt> which is to use or uses this
   *     <tt>PacketTransformer</tt>
   */
  void setConnector(AbstractRTPConnector connector) {
    if (this.connector != connector) {
      this.connector = connector;

      DatagramTransportImpl datagramTransport = this.datagramTransport;

      if (datagramTransport != null) datagramTransport.setConnector(connector);
    }
  }
  /** Starts this <tt>PacketTransformer</tt>. */
  private synchronized void start() {
    if (this.datagramTransport != null) {
      if (this.connectThread == null && dtlsTransport == null) {
        logger.warn(
            getClass().getName()
                + " has been started but has failed to establish"
                + " the DTLS connection!");
      }
      return;
    }

    if (rtcpmux && Component.RTCP == componentID) {
      // In the case of rtcp-mux, the RTCP transformer does not create
      // a DTLS session. The SRTP context (_srtpTransformer) will be
      // initialized on demand using initializeSRTCPTransformerFromRtp().
      return;
    }

    AbstractRTPConnector connector = this.connector;

    if (connector == null) throw new NullPointerException("connector");

    DtlsControl.Setup setup = this.setup;
    SecureRandom secureRandom = DtlsControlImpl.createSecureRandom();
    final DTLSProtocol dtlsProtocolObj;
    final TlsPeer tlsPeer;

    if (DtlsControl.Setup.ACTIVE.equals(setup)) {
      dtlsProtocolObj = new DTLSClientProtocol(secureRandom);
      tlsPeer = new TlsClientImpl(this);
    } else {
      dtlsProtocolObj = new DTLSServerProtocol(secureRandom);
      tlsPeer = new TlsServerImpl(this);
    }
    tlsPeerHasRaisedCloseNotifyWarning = false;

    final DatagramTransportImpl datagramTransport = new DatagramTransportImpl(componentID);

    datagramTransport.setConnector(connector);

    Thread connectThread =
        new Thread() {
          @Override
          public void run() {
            try {
              runInConnectThread(dtlsProtocolObj, tlsPeer, datagramTransport);
            } finally {
              if (Thread.currentThread().equals(DtlsPacketTransformer.this.connectThread)) {
                DtlsPacketTransformer.this.connectThread = null;
              }
            }
          }
        };

    connectThread.setDaemon(true);
    connectThread.setName(DtlsPacketTransformer.class.getName() + ".connectThread");

    this.connectThread = connectThread;
    this.datagramTransport = datagramTransport;

    boolean started = false;

    try {
      connectThread.start();
      started = true;
    } finally {
      if (!started) {
        if (connectThread.equals(this.connectThread)) this.connectThread = null;
        if (datagramTransport.equals(this.datagramTransport)) this.datagramTransport = null;
      }
    }

    notifyAll();
  }