*
 * <p><b>{@code default} method warning:</b> This class does <i>not</i> forward calls to {@code
 * default} methods. Instead, it inherits their default implementations. When those implementations
 * invoke methods, they invoke methods on the {@code ForwardingListenableFuture}.
 *
 * <p>Most subclasses can just use {@link SimpleForwardingListenableFuture}.
 *
 * @author Shardul Deo
 * @since 4.0

 * this case, you should override {@code get()} as well.
 *
 * <p><b>{@code default} method warning:</b> This class does <i>not</i> forward calls to {@code
 * default} methods. Instead, it inherits their default implementations. When those implementations
 * invoke methods, they invoke methods on the {@code ForwardingFluentFuture}.
 *
 * <h3>Extension</h3>
 *
 * This class is package-private. If you want a class like {@code FluentFuture} but with extra

 * case, you should override {@code get()} as well.
 *
 * <p><b>{@code default} method warning:</b> This class does <i>not</i> forward calls to {@code
 * default} methods. Instead, it inherits their default implementations. When those implementations
 * invoke methods, they invoke methods on the {@code ForwardingFuture}.
 *
 * <p>Most subclasses can just use {@link SimpleForwardingFuture}.
 *
 * @author Sven Mawson
 * @since 1.0
 */

   * one of the predefined {@link Policies} or specify a custom implementation. Implementations must
   * be thread-safe.
   *
   * @since 13.0
   */
  public interface Policy {

    /**
     * Called when a potential deadlock is encountered. Implementations can throw the given {@code
     * exception} and/or execute other desired logic.
     *

import junit.framework.TestCase;
import org.jspecify.annotations.NullUnmarked;

/**
 * Tests that {@link AggregateFutureState} uses the expected {@code AtomicHelper} implementation.
 *
 * <p>We have more thorough testing of {@code AtomicHelper} implementations in {@link
 * AggregateFutureStateFallbackAtomicHelperTest}. The advantage to this test is that it can run
 * under Android.
 */
@NullUnmarked
@GwtIncompatible

import junit.framework.TestCase;
import org.jspecify.annotations.NullUnmarked;

/**
 * Tests that {@link AbstractFutureState} uses the expected {@code AtomicHelper} implementation.
 *
 * <p>We have more thorough testing of {@code AtomicHelper} implementations in {@link
 * AbstractFutureFallbackAtomicHelperTest}. The advantage to this test is that it can run under
 * Android.
 */
@NullUnmarked
@GwtIncompatible
@J2ktIncompatible

import junit.framework.TestCase;
import org.jspecify.annotations.NullUnmarked;

/**
 * Tests that {@link AbstractFutureState} uses the expected {@code AtomicHelper} implementation.
 *
 * <p>We have more thorough testing of {@code AtomicHelper} implementations in {@link
 * AbstractFutureFallbackAtomicHelperTest}. The advantage to this test is that it can run under
 * Android.
 */
@NullUnmarked
@GwtIncompatible
@J2ktIncompatible

import junit.framework.TestCase;
import org.jspecify.annotations.NullUnmarked;

/**
 * Tests that {@link AggregateFutureState} uses the expected {@code AtomicHelper} implementation.
 *
 * <p>We have more thorough testing of {@code AtomicHelper} implementations in {@link
 * AggregateFutureStateFallbackAtomicHelperTest}. The advantage to this test is that it can run
 * under Android.
 */
@NullUnmarked
@GwtIncompatible

 * #get(Object, Callable)} or {@link #put(Object, Object)}, and are stored in the cache until either
 * evicted or manually invalidated. The common way to build instances is using {@link CacheBuilder}.
 *
 * <p>Implementations of this interface are expected to be thread-safe, and can be safely accessed
 * by multiple concurrent threads.
 *
 * @param <K> the type of the cache's keys, which are not permitted to be null

```

### Key Design Patterns

- **Factory**: `CrawlerClientFactory`, `ExtractorFactory` - protocol/format-specific component selection
- **Strategy**: `CrawlerClient`, `Extractor`, `Transformer` - pluggable implementations
- **Builder**: `RequestDataBuilder`, `ExtractorBuilder` - fluent construction
- **Template Method**: `AbstractCrawlerClient`, `AbstractExtractor` - common logic with overrides