*/
  protected final void notifyFailed(Throwable cause) {
    checkNotNull(cause);

    monitor.enter();
    try {
      State previous = state();
      switch (previous) {
        case NEW:
        case TERMINATED:
          throw new IllegalStateException("Failed while in state:" + previous, cause);
        case RUNNING:
        case STARTING:
        case STOPPING:

        void testGetRootCause() {
            Exception rootCause = new IllegalStateException("Test root cause");
            TransportException exception = new TransportException("Message", rootCause);

            assertEquals(rootCause, exception.getRootCause());
        }

        @Test
        @DisplayName("Should return null when no root cause")
        void testGetRootCauseWhenNull() {

        final Exception cause = new RuntimeException("Underlying error");

        // Execute
        final InvalidQueryException exception = new InvalidQueryException(null, message, cause);

        // Verify
        assertNotNull(exception);
        assertEquals(message, exception.getMessage());
        assertEquals(cause, exception.getCause());
        assertNull(exception.getMessageCode());

  }

  /**
   * Gets a {@code Throwable} cause chain as a list. The first entry in the list will be {@code
   * throwable} followed by its cause hierarchy. Note that this is a snapshot of the cause chain and
   * will not reflect any subsequent changes to the cause chain.
   *
   * <p>Here's an example of how it can be used to find specific types of exceptions in the cause
   * chain:
   *
   * <pre>

    private long extractNtStatus(Throwable cause) {
        if (cause instanceof SmbException) {
            return ((SmbException) cause).getNtStatus();
        }
        return 0;
    }

    private String extractServerMessage(Throwable cause) {
        if (cause instanceof SmbException) {
            // Try to get server message from SMB exception
            return cause.getMessage();
        }
        return null;

        final Exception cause = new RuntimeException("Test cause");

        // Execute
        final SsoMessageException exception = new SsoMessageException(null, message, cause);

        // Verify
        assertNotNull(exception);
        assertEquals(message, exception.getMessage());
        assertEquals(cause, exception.getCause());
        assertNull(exception.getMessageCode());
    }

    assertSame(cause, getRootCause(exception));
  }

  public void testGetRootCause_loop() {
    Exception cause = new Exception();
    Exception exception = new Exception(cause);
    cause.initCause(exception);
    IllegalArgumentException expected =
        assertThrows(IllegalArgumentException.class, () -> getRootCause(cause));
    assertThat(expected).hasCauseThat().isSameInstanceAs(cause);
  }

        // Test constructor with null component name and valid cause
        Throwable cause = new RuntimeException("Test cause");
        ContainerNotAvailableException exception = new ContainerNotAvailableException(null, cause);

        assertEquals("null is not available.", exception.getMessage());
        assertEquals(cause, exception.getCause());
        assertNull(exception.getComponentName());
    }

    }

    /**
     * Test constructor with cause only
     */
    public void test_constructor_withCause() {
        Exception cause = new IllegalArgumentException("Root cause");
        CrawlerSystemException exception = new CrawlerSystemException(cause);

        assertNotNull(exception);
        assertSame(cause, exception.getCause());
        // When constructed with cause only, message should be cause's toString()

    assertSame(cause, getRootCause(exception));
  }

  public void testGetRootCause_loop() {
    Exception cause = new Exception();
    Exception exception = new Exception(cause);
    cause.initCause(exception);
    IllegalArgumentException expected =
        assertThrows(IllegalArgumentException.class, () -> getRootCause(cause));
    assertThat(expected).hasCauseThat().isSameInstanceAs(cause);
  }