# Dependencies

**FastAPI** has a very powerful but intuitive **<abbr title="also known as components, resources, providers, services, injectables">Dependency Injection</abbr>** system.

It is designed to be very simple to use, and to make it very easy for any developer to integrate other components with **FastAPI**.

## What is "Dependency Injection"

# GraphQL

As **FastAPI** is based on the **ASGI** standard, it's very easy to integrate any **GraphQL** library also compatible with ASGI.

You can combine normal FastAPI *path operations* with GraphQL on the same application.

/// tip

**GraphQL** solves some very specific use cases.

It has **advantages** and **disadvantages** when compared to common **web APIs**.

   */
  @SuppressWarnings("Java7ApiChecker")
  @IgnoreJRERequirement // Users will use this only if they're already using streams.
  public static ImmutableLongArray copyOf(LongStream stream) {
    // Note this uses very different growth behavior from copyOf(Iterable) and the builder.
    long[] array = stream.toArray();
    return (array.length == 0) ? EMPTY : new ImmutableLongArray(array);
  }

  /**

   *
   * @since 22.0 (but only since 33.4.0 in the Android flavor)
   */
  public static ImmutableIntArray copyOf(IntStream stream) {
    // Note this uses very different growth behavior from copyOf(Iterable) and the builder.
    int[] array = stream.toArray();
    return (array.length == 0) ? EMPTY : new ImmutableIntArray(array);
  }

  /**

/**
 * Immutable identifier of a {@link TransferResource}.
 * The {@link TransferResource} is not immutable and does not implement {@code Objects#equals} and {@code Objects#hashCode} methods,
 * making it not very suitable for usage in collections.
 */
record TransferResourceIdentifier(String repositoryId, String repositoryUrl, String resourceName, @Nullable File file) {
    TransferResourceIdentifier(TransferResource resource) {

   */
  @SuppressWarnings("Java7ApiChecker")
  @IgnoreJRERequirement // Users will use this only if they're already using streams.
  public static ImmutableIntArray copyOf(IntStream stream) {
    // Note this uses very different growth behavior from copyOf(Iterable) and the builder.
    int[] array = stream.toArray();
    return (array.length == 0) ? EMPTY : new ImmutableIntArray(array);
  }

  /**

Because this code is executed before the application **starts** taking requests, and right after it **finishes** handling requests, it covers the whole application **lifespan** (the word "lifespan" will be important in a second 😉).

   */
  @SuppressWarnings("Java7ApiChecker")
  @IgnoreJRERequirement // Users will use this only if they're already using streams.
  public static ImmutableDoubleArray copyOf(DoubleStream stream) {
    // Note this uses very different growth behavior from copyOf(Iterable) and the builder.
    double[] array = stream.toArray();
    return (array.length == 0) ? EMPTY : new ImmutableDoubleArray(array);
  }

  /**

                    }
                }
            }
        } 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

* Implement and use well-known cryptographic tools, like Passlib and JWT tokens, etc.
* Add more granular permission controls with OAuth2 scopes where needed.
* ...etc.

Nevertheless, you might have a very specific use case where you really need to disable the API docs for some environment (e.g. for production) or depending on configurations from environment variables.

## Conditional OpenAPI from settings and env vars