final Queue<Runnable> tasks = new ArrayDeque<>();

    @Override
    public void execute(Runnable command) {
      tasks.add(command);
    }

    boolean hasNext() {
      return !tasks.isEmpty();
    }

    void runNext() {
      assertTrue("expected at least one task to run", hasNext());
      tasks.remove().run();
    }

    void runAll() {

            final TimeoutTask task = e.getElement();
            if (task.isCanceled()) {
                e.remove();
            } else if (!task.isStopped() && task.isExpired()) {
                expiredTask.add(task);
                if (!task.isPermanent()) {
                    e.remove();
                }
            }
        }

Directory for DBFlute client

manage.bat(sh) => 21 (jdbc):
A execution command of JDBC task
which gets your schema info and saves it to SchemaXML
located to the "schema" directory.
This task should be executed after ReplaceSchema task
and before other tasks(e.g. Generate, Document task).

manage.bat(sh) => 22 (doc):
A execution command of Document task
which creates documents, for example, SchemaHTML, HistoryHTML
to the "output/doc" directory.

    assertFalse(task.isDone());
    assertFalse(task.isCancelled());

    // Start the task to put it in the RUNNING state.  Have to use a separate
    // thread because the task will block on the task latch after unblocking
    // the run latch.
    exec.execute(task);
    runLatch.await();
    assertEquals(1, listenerLatch.getCount());
    assertFalse(task.isDone());
    assertFalse(task.isCancelled());

  /**
   * True if this task faker has ever had multiple tasks scheduled to run concurrently. Guarded by
   * `this`.
   */
  var isParallel = false

  /** Number of calls to [TaskRunner.Backend.execute]. Guarded by `this`. */
  var executeCallCount = 0

  /** Guarded by [taskRunner]. */
  var nanoTime = 0L
    private set

  /** Backlog of tasks to run. Only one task runs at a time. Guarded by `this`. */

  // Regression test for a deadlock where a task could be stuck busy waiting for the task to
  // transition to DONE
  public void testInterruptThrows() throws Exception {
    CountDownLatch isInterruptibleRegistered = new CountDownLatch(1);
    SettableFuture<String> taskResult = SettableFuture.create();
    InterruptibleTask<String> task =
        new InterruptibleTask<String>() {
          @Override

        TaskProvider<Docbook2Xhtml> dslHtml = tasks.register("dslHtml", Docbook2Xhtml.class, task -> {
            task.setGroup("documentation");
            task.setDescription("Generates DSL reference HTML documentation.");
            task.onlyIf(t -> !extension.getQuickFeedback().get());

            task.source(dslStandaloneDocbook);
            task.getStylesheetDirectory().convention(dslReference.getStylesheetDirectory());

  @Override
  public ListenableFuture<?> submit(Runnable task) {
    return (ListenableFuture<?>) super.submit(task);
  }

  @CanIgnoreReturnValue // TODO(kak): consider removing this
  @Override
  public <T extends @Nullable Object> ListenableFuture<T> submit(
      Runnable task, @ParametricNullness T result) {
    return (ListenableFuture<T>) super.submit(task, result);
  }

        try {
          while (true) {
            currentThread.name = task.name
            val delayNanos =
              logger.logElapsed(task, task.queue!!) {
                task.runOnce()
              }

            // A task ran successfully. Update the execution state and take the next task.
            task = withLock {
              afterRun(task, delayNanos, true)
              awaitTaskToRun()
            } ?: return

      "FINE: Q10000 scheduled after 100 µs: task",
      "FINE: Q10000 starting              : task",
      "FINE: Q10000 finished run in   0 µs: task",
      "FINE: Q10000 run again after  50 µs: task",
      "FINE: Q10000 starting              : task",
      "FINE: Q10000 finished run in   0 µs: task",
      "FINE: Q10000 run again after 150 µs: task",
      "FINE: Q10000 starting              : task",