# Custom Request and APIRoute class

In some cases, you may want to override the logic used by the `Request` and `APIRoute` classes.

In particular, this may be a good alternative to logic in a middleware.

For example, if you want to read or manipulate the request body before it is processed by your application.

/// danger

This is an "advanced" feature.

If you are just starting with **FastAPI** you might want to skip this section.

///

import static com.google.common.util.concurrent.Futures.immediateFailedFuture;

import com.google.common.annotations.GwtCompatible;
import java.util.concurrent.Future;
import javax.annotation.CheckForNull;

/**
 * Classes and futures used in {@link FuturesGetCheckedTest} and {@link FuturesGetUncheckedTest}.
 */
@GwtCompatible
final class FuturesGetCheckedInputs {
  static final Exception CHECKED_EXCEPTION = new Exception("mymessage");

          public void onFailure(Throwable t) {}
        },
        directExecutor());
    assertThat(called[0]).isTrue();
  }

  // Avoid trouble with automatic mapping between JRE and Kotlin runtime classes.
  static class CustomRuntimeException extends RuntimeException {}

  public void testCatching() throws Exception {
    FluentFuture<?> f =
        FluentFuture.from(immediateFailedFuture(new CustomRuntimeException()))

        <module name="UnusedImports"/>
        <module name="IllegalImport">
            <!--
                We shouldn't use jdk.internal types.
                
                com.beust and org.testng.collections has classes that look like Guava.

                We prefer to import javax.annotation and fully-qualify references to org.jetbrains.annotations.
            -->

        properties.put(
                MavenArtifactProperties.CONSTITUTES_BUILD_PATH,
                String.valueOf(this.pathTypes.contains(JavaPathType.CLASSES)));
        this.properties = Collections.unmodifiableMap(properties);
    }

    @Override
    public String id() {
        return id;
    }

    @Override
    public String getId() {

  // One of Never, PreemptLowerPriority.
  // Defaults to PreemptLowerPriority if unset.
  // +optional
  optional string preemptionPolicy = 5;
}

// PriorityClassList is a collection of priority classes.
message PriorityClassList {
  // Standard list metadata
  // More info: https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#metadata
  // +optional

 * appropriate primitive specialization such as {@code IntPredicate}) instead whenever possible.
 * Otherwise, at least reduce <i>explicit</i> dependencies on this type by using lambda expressions
 * or method references instead of classes, leaving your code easier to migrate in the future.
 *
 * <p>To use a reference of this type (say, named {@code guavaPredicate}) in a context where {@code
 * java.util.function.Predicate} is expected, use the method reference {@code

   * can suppress it with {@code FeatureSpecificTestSuiteBuilder.suppressing()} while we figure out
   * what to do with <a
   * href="https://github.com/openjdk/jdk/blob/c25c4896ad9ef031e3cddec493aef66ff87c48a7/src/java.base/share/classes/java/util/concurrent/ConcurrentHashMap.java#L4830">{@code
   * ConcurrentHashMap} support for {@code entrySet().add()}</a>.
   */
  @J2ktIncompatible
  @GwtIncompatible // reflection

   * can suppress it with {@code FeatureSpecificTestSuiteBuilder.suppressing()} while we figure out
   * what to do with <a
   * href="https://github.com/openjdk/jdk/blob/c25c4896ad9ef031e3cddec493aef66ff87c48a7/src/java.base/share/classes/java/util/concurrent/ConcurrentHashMap.java#L4830">{@code
   * ConcurrentHashMap} support for {@code entrySet().add()}</a>.
   */
  @J2ktIncompatible
  @GwtIncompatible // reflection

  private Class<?> settableFutureClass;
  private Class<?> abstractFutureClass;

  @Override
  protected void setUp() throws Exception {
    // Load the "normal" copy of SettableFuture and related classes.
    SettableFuture<?> unused = SettableFuture.create();
    // Hack to load AbstractFuture et. al. in a new classloader so that it re-reads the cancellation