Package com.linecorp.armeria.common.util

Interface Unwrappable

All Known Subinterfaces:
Backoff, Client<I,​O>, GrpcService, HttpClient, HttpService, HttpServiceWithRoutes, PooledHttpClient, PooledHttpService, PooledWebClient, RequestContextStorage, RpcClient, RpcService, RpcServiceWithRoutes, Service<I,​O>, ServiceWithRoutes<I,​O>, THttpClient, TransientHttpService, TransientRpcService, TransientService<I,​O>, WebClient
All Known Implementing Classes:
AbstractBackoff, AbstractCircuitBreakerClient, AbstractCompositeService, AbstractConcurrencyLimitingClient, AbstractHttpService, AbstractPooledHttpService, AbstractRetryingClient, AbstractThrottlingService, AbstractUnaryGrpcService, AbstractUnsafeUnaryGrpcService, AbstractUnwrappable, AuthService, BackoffWrapper, BraveClient, BraveService, CircuitBreakerClient, CircuitBreakerRpcClient, ConcurrencyLimitingClient, ContentPreviewingClient, ContentPreviewingService, CorsService, DecodingClient, DecoratingClient, DecoratingService, DocService, EncodingService, FileService, HealthCheckService, JettyService, LoggingClient, LoggingRpcClient, LoggingService, MetricCollectingClient, MetricCollectingRpcClient, MetricCollectingService, PrometheusExpositionService, RedirectService, RequestContextStorageWrapper, RetryingClient, RetryingRpcClient, SimpleCompositeRpcService, SimpleCompositeService, SimpleDecoratingClient, SimpleDecoratingHttpClient, SimpleDecoratingHttpService, SimpleDecoratingRpcClient, SimpleDecoratingRpcService, SimpleDecoratingService, SimplePooledDecoratingHttpClient, SimplePooledDecoratingHttpService, ThriftCallService, ThrottlingRpcService, ThrottlingService, THttpService, TomcatService, UserClient
public interface Unwrappable
Provides a way to unwrap an object in decorator pattern, similar to down-casting in an inheritance pattern.

  • Method Summary

    Modifier and Type Method Description
    default <T> T as​(Class<T> type)
    Unwraps this object into the object of the specified type.
    default Unwrappable unwrap()
    Unwraps this object and returns the object being decorated.

  • Method Details

    • as

      @Nullable default <T> T as​(Class<T> type)
      Unwraps this object into the object of the specified type. Use this method instead of an explicit downcast. For example: 
      
 class Foo {}

 class Bar<T> extends AbstractWrapper<T> {
     Bar(T delegate) {
         super(delegate);
     }
 }

 class Qux<T> extends AbstractWrapper<T> {
     Qux(T delegate) {
         super(delegate);
     }
 }

 Qux qux = new Qux(new Bar(new Foo()));
 Foo foo = qux.as(Foo.class);
 Bar bar = qux.as(Bar.class);
      Parameters:
      type - the type of the object to return
      Returns:
      the object of the specified type if found, or null if not found.

    • unwrap

      default Unwrappable unwrap()
      Unwraps this object and returns the object being decorated. If this Unwrappable is the innermost object, this method returns itself. For example: 
      
 class Foo implements Unwrappable {}

 class Bar<T extends Unwrappable> extends AbstractUnwrappable<T> {
     Bar(T delegate) {
         super(delegate);
     }
 }

 class Qux<T extends Unwrappable> extends AbstractUnwrappable<T> {
     Qux(T delegate) {
         super(delegate);
     }
 }

 Foo foo = new Foo();
 assert foo.unwrap() == foo;

 Bar<Foo> bar = new Bar<>(foo);
 assert bar.unwrap() == foo;

 Qux<Bar<Foo>> qux = new Qux<>(bar);
 assert qux.unwrap() == bar;
 assert qux.unwrap().unwrap() == foo;