# Dependencies - `Depends()` and `Security()`

## `Depends()`

Dependencies are handled mainly with the special function `Depends()` that takes a callable.

Here is the reference for it and its parameters.

You can import it directly from `fastapi`:

```python
from fastapi import Depends
```

::: fastapi.Depends

## `Security()`

 */
package jcifs;

import java.util.List;
import java.util.concurrent.Callable;

/**
 * Handle for receiving change notifications from an SMB server
 *
 *
 * @author mbechler
 *
 */
public interface SmbWatchHandle extends AutoCloseable, Callable<List<FileNotifyInformation>> {

    /**
     * Get the next set of changes
     *

    private final CountDownLatch returned = new CountDownLatch(1);
    private Object proxy;

    @SuppressWarnings("unchecked") // proxy for a generic class
    <V> Callable<V> waitFor(Callable<V> callable) {
      return waitFor(callable, Callable.class);
    }

    @SuppressWarnings("unchecked") // proxy for a generic class
    <V> ClosingCallable<V> waitFor(ClosingCallable<V> closingCallable) {

import com.google.common.collect.ForwardingObject;
import com.google.common.collect.ImmutableMap;
import java.util.Map;
import java.util.concurrent.Callable;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.ExecutionException;
import org.jspecify.annotations.Nullable;

/**
 * A cache which forwards all its method calls to another cache. Subclasses should override one or

Existing Groovy methods will not be removed immediately.

## Consequences

* If we would have used `Closure`, we must instead use `Action<T>`, `Spec<T>`, `Callable<T>`, or `Transformer<OUT, IN>`.
* We need to ensure all APIs that are exposed in the Groovy DSL go through runtime decoration.
Runtime decoration mixes in methods that use Groovy Closures to maintain consistent behavior in Groovy DSL.

    return doMultithreadedLoop(
        new Callable<Long>() {
          @Override
          public Long call() {
            return runAddSingleThread(reps);
          }
        });
  }

  @Benchmark
  long addRemove(int reps) throws ExecutionException, InterruptedException {
    return doMultithreadedLoop(
        new Callable<Long>() {
          @Override
          public Long call() {

    private final CountDownLatch returned = new CountDownLatch(1);
    private Object proxy;

    @SuppressWarnings("unchecked") // proxy for a generic class
    <V> Callable<V> waitFor(Callable<V> callable) {
      return waitFor(callable, Callable.class);
    }

    @SuppressWarnings("unchecked") // proxy for a generic class
    <V> ClosingCallable<V> waitFor(ClosingCallable<V> closingCallable) {

import com.google.common.annotations.GwtIncompatible;
import com.google.common.annotations.J2ktIncompatible;
import com.google.common.collect.ImmutableList;
import java.util.List;
import java.util.concurrent.Callable;
import java.util.concurrent.TimeUnit;
import junit.framework.TestCase;
import org.jspecify.annotations.NullUnmarked;

/**
 * Tests for {@link AbstractListeningExecutorService}.
 *
 * @author Colin Decker
 */

import com.google.common.annotations.GwtIncompatible;
import com.google.common.annotations.J2ktIncompatible;
import com.google.common.collect.ImmutableList;
import java.util.List;
import java.util.concurrent.Callable;
import java.util.concurrent.TimeUnit;
import junit.framework.TestCase;
import org.jspecify.annotations.NullUnmarked;

/**
 * Tests for {@link AbstractListeningExecutorService}.
 *
 * @author Colin Decker
 */

            address.firstCalledName();
            address.nextCalledName(mockContext);
            address.toInetAddress();
            address.unwrap(Address.class);
        }, "All Address interface methods should be callable");
    }

    @Test
    @DisplayName("unwrap method should return correct type when supported")
    void testUnwrapMethodContract() throws Exception {
        // Given