Align HttpRequester/StreamingHttpRequester with blocking variants

Motivation:

`BlockingHttpRequester` and `BlockingStreamingHttpRequester` implement
`GracefulAutoCloseable` interface and in result can be used in
try-with-resources. For some reason, our `HttpRequester` and
`StreamingHttpRequester` don't but their client and connection
interfaces do.

Modifications:

- Promote `GracefulAutoCloseable` interface from `HttpClient`
and `HttpConnection` to `HttpRequester`.
- Promote `GracefulAutoCloseable` interface from `StreamingHttpClient`
and `StreamingHttpConnection` to `StreamingHttpRequester`.

Result:

All requester/client/connection interfaces are consistent across all 4
API variants.

Author: idelpivnitskiy

servicetalk-http-api/src/main/java/io/servicetalk/http/api/HttpClient.java

@@ -15,16 +15,13 @@
  */
 package io.servicetalk.http.api;
 
-import io.servicetalk.concurrent.GracefulAutoCloseable;
 import io.servicetalk.concurrent.api.Single;
 
-import static io.servicetalk.concurrent.internal.FutureUtils.awaitTermination;
-
 /**
  * Provides a means to issue requests against HTTP service. The implementation is free to maintain a collection of
  * {@link HttpConnection} instances and distribute calls to {@link #request(HttpRequest)} amongst this collection.
  */
-public interface HttpClient extends HttpRequester, GracefulAutoCloseable {
+public interface HttpClient extends HttpRequester {
     /**
      * Reserve an {@link HttpConnection} based on provided {@link HttpRequestMetaData}.
      * <p>
@@ -63,14 +60,4 @@ default BlockingStreamingHttpClient asBlockingStreamingClient() {
     default BlockingHttpClient asBlockingClient() {
         return asStreamingClient().asBlockingClient();
     }
-
-    @Override
-    default void close() throws Exception {
-        awaitTermination(closeAsync().toFuture());
-    }
-
-    @Override
-    default void closeGracefully() throws Exception {
-        awaitTermination(closeAsyncGracefully().toFuture());
-    }
 }

servicetalk-http-api/src/main/java/io/servicetalk/http/api/HttpConnection.java

@@ -15,16 +15,13 @@
  */
 package io.servicetalk.http.api;
 
-import io.servicetalk.concurrent.GracefulAutoCloseable;
 import io.servicetalk.concurrent.PublisherSource;
 import io.servicetalk.concurrent.api.Publisher;
 
-import static io.servicetalk.concurrent.internal.FutureUtils.awaitTermination;
-
 /**
  * Represents a single fixed connection to a HTTP server.
  */
-public interface HttpConnection extends HttpRequester, GracefulAutoCloseable {
+public interface HttpConnection extends HttpRequester {
     /**
      * Get the {@link HttpConnectionContext}.
      *
@@ -69,14 +66,4 @@ default BlockingStreamingHttpConnection asBlockingStreamingConnection() {
     default BlockingHttpConnection asBlockingConnection() {
         return asStreamingConnection().asBlockingConnection();
     }
-
-    @Override
-    default void close() throws Exception {
-        awaitTermination(closeAsync().toFuture());
-    }
-
-    @Override
-    default void closeGracefully() throws Exception {
-        awaitTermination(closeAsyncGracefully().toFuture());
-    }
 }

servicetalk-http-api/src/main/java/io/servicetalk/http/api/HttpRequester.java

@@ -15,13 +15,16 @@
  */
 package io.servicetalk.http.api;
 
+import io.servicetalk.concurrent.GracefulAutoCloseable;
 import io.servicetalk.concurrent.api.ListenableAsyncCloseable;
 import io.servicetalk.concurrent.api.Single;
 
+import static io.servicetalk.concurrent.internal.FutureUtils.awaitTermination;
+
 /**
  * Provides a means to make a HTTP request.
  */
-public interface HttpRequester extends HttpRequestFactory, ListenableAsyncCloseable {
+public interface HttpRequester extends HttpRequestFactory, ListenableAsyncCloseable, GracefulAutoCloseable {
     /**
      * Send a {@code request}.
      *
@@ -46,4 +49,14 @@ public interface HttpRequester extends HttpRequestFactory, ListenableAsyncClosea
      * @return a {@link HttpResponseFactory}.
      */
     HttpResponseFactory httpResponseFactory();
+
+    @Override
+    default void close() throws Exception {
+        awaitTermination(closeAsync().toFuture());
+    }
+
+    @Override
+    default void closeGracefully() throws Exception {
+        awaitTermination(closeAsyncGracefully().toFuture());
+    }
 }

servicetalk-http-api/src/main/java/io/servicetalk/http/api/StreamingHttpClient.java

@@ -15,16 +15,13 @@
  */
 package io.servicetalk.http.api;
 
-import io.servicetalk.concurrent.GracefulAutoCloseable;
 import io.servicetalk.concurrent.api.Single;
 
-import static io.servicetalk.concurrent.internal.FutureUtils.awaitTermination;
-
 /**
  * The equivalent of {@link HttpClient} but that accepts {@link StreamingHttpRequest} and returns
  * {@link StreamingHttpResponse}.
  */
-public interface StreamingHttpClient extends FilterableStreamingHttpClient, GracefulAutoCloseable {
+public interface StreamingHttpClient extends FilterableStreamingHttpClient {
     /**
      * Reserve a {@link StreamingHttpConnection} based on provided {@link HttpRequestMetaData}.
      * <p>
@@ -66,14 +63,4 @@ public interface StreamingHttpClient extends FilterableStreamingHttpClient, Grac
      * @return a {@link BlockingHttpClient} representation of this {@link StreamingHttpClient}.
      */
     BlockingHttpClient asBlockingClient();
-
-    @Override
-    default void close() throws Exception {
-        awaitTermination(closeAsync().toFuture());
-    }
-
-    @Override
-    default void closeGracefully() throws Exception {
-        awaitTermination(closeAsyncGracefully().toFuture());
-    }
 }

servicetalk-http-api/src/main/java/io/servicetalk/http/api/StreamingHttpConnection.java

@@ -15,15 +15,11 @@
  */
 package io.servicetalk.http.api;
 
-import io.servicetalk.concurrent.GracefulAutoCloseable;
-
-import static io.servicetalk.concurrent.internal.FutureUtils.awaitTermination;
-
 /**
  * The equivalent of {@link HttpConnection} but that accepts {@link StreamingHttpRequest} and returns
  * {@link StreamingHttpResponse}.
  */
-public interface StreamingHttpConnection extends FilterableStreamingHttpConnection, GracefulAutoCloseable {
+public interface StreamingHttpConnection extends FilterableStreamingHttpConnection {
     /**
      * Convert this {@link StreamingHttpConnection} to the {@link HttpConnection} API.
      * <p>
@@ -50,14 +46,4 @@ public interface StreamingHttpConnection extends FilterableStreamingHttpConnecti
      * @return a {@link BlockingHttpConnection} representation of this {@link StreamingHttpConnection}.
      */
     BlockingHttpConnection asBlockingConnection();
-
-    @Override
-    default void close() throws Exception {
-        awaitTermination(closeAsync().toFuture());
-    }
-
-    @Override
-    default void closeGracefully() throws Exception {
-        awaitTermination(closeAsyncGracefully().toFuture());
-    }
 }

servicetalk-http-api/src/main/java/io/servicetalk/http/api/StreamingHttpRequester.java

@@ -15,14 +15,18 @@
  */
 package io.servicetalk.http.api;
 
+import io.servicetalk.concurrent.GracefulAutoCloseable;
 import io.servicetalk.concurrent.api.ListenableAsyncCloseable;
 import io.servicetalk.concurrent.api.Single;
 
+import static io.servicetalk.concurrent.internal.FutureUtils.awaitTermination;
+
 /**
  * The equivalent of {@link HttpRequester} but that accepts {@link StreamingHttpRequest} and returns
  * {@link StreamingHttpResponse}.
  */
-public interface StreamingHttpRequester extends StreamingHttpRequestFactory, ListenableAsyncCloseable {
+public interface StreamingHttpRequester extends StreamingHttpRequestFactory, ListenableAsyncCloseable,
+                                                GracefulAutoCloseable {
     /**
      * Send a {@code request}.
      *
@@ -47,4 +51,14 @@ public interface StreamingHttpRequester extends StreamingHttpRequestFactory, Lis
      * @return a {@link StreamingHttpResponseFactory}.
      */
     StreamingHttpResponseFactory httpResponseFactory();
+
+    @Override
+    default void close() throws Exception {
+        awaitTermination(closeAsync().toFuture());
+    }
+
+    @Override
+    default void closeGracefully() throws Exception {
+        awaitTermination(closeAsyncGracefully().toFuture());
+    }
 }

servicetalk-http-netty/src/main/java/io/servicetalk/http/netty/H2ClientParentConnectionContext.java

@@ -45,6 +45,7 @@
 import io.servicetalk.transport.api.ConnectionObserver.StreamObserver;
 import io.servicetalk.transport.api.IoThreadFactory;
 import io.servicetalk.transport.api.SslConfig;
+import io.servicetalk.transport.netty.internal.ChannelCloseUtils;
 import io.servicetalk.transport.netty.internal.ChannelInitializer;
 import io.servicetalk.transport.netty.internal.CloseHandler;
 import io.servicetalk.transport.netty.internal.DefaultNettyConnection;
@@ -86,7 +87,6 @@
 import static io.servicetalk.http.netty.AbstractStreamingHttpConnection.ZERO_MAX_CONCURRENCY_EVENT;
 import static io.servicetalk.http.netty.HeaderUtils.OBJ_EXPECT_CONTINUE;
 import static io.servicetalk.http.netty.HttpDebugUtils.showPipeline;
-import static io.servicetalk.transport.netty.internal.ChannelCloseUtils.close;
 import static io.servicetalk.transport.netty.internal.ChannelSet.CHANNEL_CLOSEABLE_KEY;
 import static io.servicetalk.transport.netty.internal.CloseHandler.forNonPipelined;
 import static io.servicetalk.transport.netty.internal.NettyPipelineSslUtils.extractSslSession;
@@ -145,14 +145,14 @@ protected void handleSubscribe(final Subscriber<? super H2ClientParentConnection
                             delayedCancellable, shouldWaitForSslHandshake(sslSession, sslConfig),
                             allowDropTrailersReadFromTransport, config.headersFactory(), reqRespFactory, observer);
                 } catch (Throwable cause) {
-                    close(channel, cause);
+                    ChannelCloseUtils.close(channel, cause);
                     deliverErrorFromSource(subscriber, cause);
                     return;
                 }
                 try {
                     subscriber.onSubscribe(delayedCancellable);
                 } catch (Throwable cause) {
-                    close(channel, cause);
+                    ChannelCloseUtils.close(channel, cause);
                     handleExceptionFromOnSubscribe(subscriber, cause);
                     return;
                 }
@@ -215,7 +215,7 @@ void tryCompleteSubscriber() {
         @Override
         boolean tryFailSubscriber(Throwable cause) {
             if (subscriber != null) {
-                close(parentContext.nettyChannel(), cause);
+                ChannelCloseUtils.close(parentContext.nettyChannel(), cause);
                 Subscriber<? super H2ClientParentConnection> subscriberCopy = subscriber;
                 subscriber = null;
                 subscriberCopy.onError(cause);
@@ -391,7 +391,7 @@ private void childChannelActive(Future<Http2StreamChannel> future,
                 } catch (Throwable cause) {
                     if (streamChannel != null) {
                         try {
-                            close(streamChannel, cause);
+                            ChannelCloseUtils.close(streamChannel, cause);
                         } catch (Throwable unexpected) {
                             addSuppressed(unexpected, cause);
                             LOGGER.warn("Unexpected exception while handling the original cause", unexpected);