# Dependencies { #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" { #what-is-dependency-injection }

        // When
        outputStream = new SmbFileOutputStream(mockFile);

        // Then
        assertNotNull(outputStream);

        // Verify the AutoCloseable resources were closed
        verify(autoCloseableMockTreeHandle).close();
        verify(autoCloseableMockFileHandle).close();
    }

    @Test
    void testConstructorWithAppendFlag() throws IOException, CIFSException {

  - The following APIs are no longer served by default:

    - All resources under `apps/v1beta1` and `apps/v1beta2` - use `apps/v1` instead
    - `daemonsets`, `deployments`, `replicasets` resources under `extensions/v1beta1` - use `apps/v1` instead
    - `networkpolicies` resources under `extensions/v1beta1` - use `networking.k8s.io/v1` instead
    - `podsecuritypolicies` resources under `extensions/v1beta1` - use `policy/v1beta1` instead

       * consistency with how weak references are cleared). That's a behavior change -- arguably the
       * removal of a feature.
       *
       * Fortunately, exceptions rarely contain references to expensive resources.
       */

      //
      seenExceptionsLocal = newConcurrentHashSet();
      /*
       * Other handleException() callers may see this as soon as we publish it. We need to populate

  /** Returns the trailers after the HTTP response if they're ready. May be empty. */
  @Throws(IOException::class)
  fun peekTrailers(): Headers?

  /**
   * Cancel this stream. Resources held by this stream will be cleaned up, though not synchronously.
   * That may happen later by the connection pool thread.
   */
  fun cancel()

  /**

        }
    }

    /**
     * An application extending this class must provide an implementation for this method that returns new user
     * credentials try try when accessing SMB resources described by the <code>getRequestingURL</code> and
     * <code>getRequestingException</code> methods.
     * If this method returns <code>null</code> the <code>SmbAuthException</code> that triggered the authenticator check will

import java.nio.file.Files;
import java.util.logging.Logger;

/**
 * ContentCache is a class that provides a way to cache content either in memory or in a file.
 * It implements the Closeable interface to ensure that resources are properly released.
 *
 * <p>This class supports two types of content caching:
 * <ul>
 *   <li>In-memory caching using a byte array</li>
 *   <li>File-based caching using a File object</li>
 * </ul>
 *

import org.junit.jupiter.api.Test

@Tag("Slow")
class OsgiTest {
  private lateinit var testResourceDir: Path
  private lateinit var workspaceDir: Path

  @BeforeEach
  fun setUp() {
    testResourceDir = "./build/resources/test/okhttp3/osgi".toPath()
    workspaceDir = testResourceDir / "workspace"

    // Ensure we start from scratch.
    fileSystem.deleteRecursively(workspaceDir)
    fileSystem.createDirectories(workspaceDir)
  }

    }

    @Override
    public int available() throws IOException {
        return fileInputStream.available();
    }

    /**
     * Closes this input stream and releases any system resources associated with the stream.
     * @throws IOException if an I/O error occurs.
     */
    @Override
    public void close() throws IOException {
        try {
            fileInputStream.close();
        } finally {

- **Scheduling**
  - [alpha] Added support for accounting opaque integer resources. ([docs](http://kubernetes.io/docs/user-guide/compute-resources/#opaque-integer-resources-alpha-feature)) ([kubernetes/features#76](https://github.com/kubernetes/enhancements/issues/76))