@GuardedBy("lock")
    private int runningTasks = 0;

    @GuardedBy("lock")
    private boolean shutdown = false;

    @Override
    public void execute(Runnable command) {
      startTask();
      try {
        command.run();
      } finally {
        endTask();
      }
    }

    @Override
    public boolean isShutdown() {
      synchronized (lock) {
        return shutdown;

                }
            }
        } catch (IOException | XMLStreamException e) {
            // The root locator can be used very early during the setup of Maven,
            // even before the arguments from the command line are parsed.  Any exception
            // that would happen here should cause the build to fail at a later stage
            // (when actually parsing the POM) and will lead to a better exception being

        final JobProcess jobProcess = runningProcessMap.get(sessionId);
        if (jobProcess == null) {
            throw new JobNotFoundException("Job for " + sessionId + " is not found.");
        }
        try {
            final OutputStream out = jobProcess.getProcess().getOutputStream();
            IOUtils.write(command + "\n", out, Constants.CHARSET_UTF_8);

    /**
     * Gets the user properties to use for interpolation and profile activation. The user properties have been
     * configured directly by the user on his discretion, e.g. via the {@code -Dkey=value} parameter on the command
     * line.
     *
     * @return The user properties, never {@code null}.
     */
    Map<String, String> getUserProperties();

    /**
     * Gets the base directory of the current project (if any).
     *

                            }
                            if (Constants.CRAWLER_PROCESS_COMMAND_THREAD_DUMP.equals(command)) {
                                ThreadDumpUtil.printThreadDump();
                            } else {
                                logger.warn("Unknown process command: {}", command);
                            }

    protected int executeCommand(final String[] commands, final String username, final String password) {
        if (commands == null || commands.length == 0) {
            throw new CommandExecutionException("command is empty.");
        }

        if (logger.isInfoEnabled()) {
            logger.info("Command: {}", String.join(" ", commands));
        }

        final String[] cmds = stream(commands).get(stream -> stream.map(s -> {

        final String id = form.id;
        crawlingInfoService.getCrawlingInfo(id).ifPresent(entity -> {
            try {
                processHelper.sendCommand(entity.getSessionId(), Constants.CRAWLER_PROCESS_COMMAND_THREAD_DUMP);
                saveInfo(messages -> messages.addSuccessPrintThreadDump(GLOBAL));
            } catch (final Exception e) {
                logger.warn("Failed to print a thread dump.", e);

    SessionData getData();

    /**
     * Returns immutable user properties to use for interpolation. The user properties have been configured directly
     * by the user, e.g. via the {@code -Dkey=value} parameter on the command line.
     *
     * @return the user properties, never {@code null}
     */
    @Nonnull
    Map<String, String> getUserProperties();

    /**

     * being passed into the session. This is also the potentially constrained set of projects by using --projects
     * on the command line.
     */
    private List<MavenProject> projects;

    /**
     * The full set of projects before any potential constraining by --projects. Useful in the case where you want to

        final String commandTimeoutStr = fessConfig.getSystemProperty("thumbnail.command.timeout");
        if (commandTimeoutStr != null) {
            commandTimeout = Long.valueOf(commandTimeoutStr);
        }
        final String commandDestroyTimeoutStr = fessConfig.getSystemProperty("thumbnail.command.destroy.timeout");
        if (commandDestroyTimeoutStr != null) {