import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * An abstract implementation of {@link ListenableFuture}, intended for advanced users only. More
 * common ways to create a {@code ListenableFuture} include instantiating a {@link SettableFuture},
 * submitting a task to a {@link ListeningExecutorService}, and deriving a {@code Future} from an

   * on {@link Platform} so that we can have different behavior in GWT.
   *
   * <p>This implementation tries to be smart in a number of ways. It recognizes cases where the
   * negation is cheaper to precompute than the matcher itself; it tries to build small hash tables
   * for matchers that only match a few characters, and so on. In the worst-case scenario, it

   * on {@link Platform} so that we can have different behavior in GWT.
   *
   * <p>This implementation tries to be smart in a number of ways. It recognizes cases where the
   * negation is cheaper to precompute than the matcher itself; it tries to build small hash tables
   * for matchers that only match a few characters, and so on. In the worst-case scenario, it

 * {@code Type}, for example {@link #isSubtypeOf}, {@link #isArray} and {@link #getComponentType}.
 * It also provides additional utilities such as {@link #getTypes}, {@link #resolveType}, etc.
 *
 * <p>There are three ways to get a {@code TypeToken} instance:
 *
 * <ul>
 *   <li>Wrap a {@code Type} obtained via reflection. For example: {@code
 *       TypeToken.of(method.getGenericReturnType())}.