* This method is not supported in the Fess implementation.
     *
     * @param checker the credential checker to use
     * @throws UnsupportedOperationException always thrown as this method is not supported
     */
    @Override
    protected void checkCredential(final TypicalLoginAssist<String, FessUserBean, FessUser>.CredentialChecker checker) {

如此一來我們就能「參數化」相依，現在它內部含有 `"bar"`，作為屬性 `checker.fixed_content`。

## 將實例作為相依使用 { #use-the-instance-as-a-dependency }

然後，我們可以在 `Depends(checker)` 中使用這個 `checker`，而不是 `Depends(FixedContentQueryChecker)`，因為相依是那個實例 `checker`，不是類別本身。

當解析相依時，**FastAPI** 會像這樣呼叫這個 `checker`：

```Python
checker(q="somequery")
```

...並將其回傳值，作為相依的值，以參數 `fixed_content_included` 傳給我們的「路徑操作函式」：

  }

  @Override
  @SuppressWarnings("CatchingUnchecked") // sneaky checked exception
  public void addListener(Runnable listener, Executor executor) {
    checkNotNull(listener, "Runnable was null.");
    checkNotNull(executor, "Executor was null.");
    try {
      executor.execute(listener);
    } catch (Exception e) { // sneaky checked exception

   * fact the static type of {@link Throwable} is occasionally justified even for a method with no
   * {@code throws} clause: Some such methods can in fact throw a checked exception (e.g., by
   * calling code written in Kotlin).) Typically, we want to let a {@link Throwable} from such a
   * method propagate untouched, just as we'd typically let it do for a non-reflective call.

   * <ul>
   *   <li>All visible static methods are checked such that passing null for any parameter that's
   *       not annotated nullable (according to the rules of {@link NullPointerTester}) should throw
   *       {@link NullPointerException}.
   *   <li>If there is any visible constructor or visible static factory method declared by the
   *       class, all visible instance methods will be checked too using the instance created by

   * fact the static type of {@link Throwable} is occasionally justified even for a method with no
   * {@code throws} clause: Some such methods can in fact throw a checked exception (e.g., by
   * calling code written in Kotlin).) Typically, we want to let a {@link Throwable} from such a
   * method propagate untouched, just as we'd typically let it do for a non-reflective call.

   * fact the static type of {@link Throwable} is occasionally justified even for a method with no
   * {@code throws} clause: Some such methods can in fact throw a checked exception (e.g., by
   * calling code written in Kotlin).) Typically, we want to let a {@link Throwable} from such a
   * method propagate untouched, just as we'd typically let it do for a non-reflective call.

    }
    return null;
  }

  @Override
  public SortedMultiset<E> subMultiset(
      E fromElement, BoundType fromBoundType, E toElement, BoundType toBoundType) {
    // These are checked elsewhere, but NullPointerTester wants them checked eagerly.
    checkNotNull(fromBoundType);
    checkNotNull(toBoundType);
    return tailMultiset(fromElement, fromBoundType).headMultiset(toElement, toBoundType);
  }

   * <ul>
   *   <li>All visible static methods are checked such that passing null for any parameter that's
   *       not annotated nullable (according to the rules of {@link NullPointerTester}) should throw
   *       {@link NullPointerException}.
   *   <li>If there is any visible constructor or visible static factory method declared by the
   *       class, all visible instance methods will be checked too using the instance created by

      @ParametricNullness E fromElement,
      BoundType fromBoundType,
      @ParametricNullness E toElement,
      BoundType toBoundType) {
    // These are checked elsewhere, but NullPointerTester wants them checked eagerly.
    checkNotNull(fromBoundType);
    checkNotNull(toBoundType);
    return tailMultiset(fromElement, fromBoundType).headMultiset(toElement, toBoundType);
  }