Polish ChannelSendOperator

spring-web/src/main/java/org/springframework/http/server/reactive/ChannelSendOperator.java

@@ -50,7 +50,9 @@ public class ChannelSendOperator<T> extends Mono<Void> implements Scannable {
 	private final Flux<T> source;
 
 
-	public ChannelSendOperator(Publisher<? extends T> source, Function<Publisher<T>, Publisher<Void>> writeFunction) {
+	public ChannelSendOperator(Publisher<? extends T> source, Function<Publisher<T>,
+			Publisher<Void>> writeFunction) {
+
 		this.source = Flux.from(source);
 		this.writeFunction = writeFunction;
 	}
@@ -79,8 +81,10 @@ public class ChannelSendOperator<T> extends Mono<Void> implements Scannable {
 	private final class WriteWithBarrier 
 			implements Publisher<T>, CoreSubscriber<T>, Subscription {
 
-		private final CoreSubscriber<? super Void> subscriber;
+		/* Downstream write completion subscriber */
+		private final CoreSubscriber<? super Void> completionSubscriber;
 
+		/* Upstream write source subscription */
 		@Nullable
 		private Subscription subscription;
 
@@ -109,10 +113,12 @@ public class ChannelSendOperator<T> extends Mono<Void> implements Scannable {
 		@Nullable
 		private Subscriber<? super T> writeSubscriber;
 
-		WriteWithBarrier(CoreSubscriber<? super Void> subscriber) {
-			this.subscriber = subscriber;
+
+		WriteWithBarrier(CoreSubscriber<? super Void> completionSubscriber) {
+			this.completionSubscriber = completionSubscriber;
 		}
 
+
 		@Override
 		public void cancel() {
 			Subscription s = this.subscription;
@@ -124,23 +130,23 @@ public class ChannelSendOperator<T> extends Mono<Void> implements Scannable {
 
 		@Override
 		public Context currentContext() {
-			return subscriber.currentContext();
+			return completionSubscriber.currentContext();
 		}
 
 		@Override
 		public final void onComplete() {
 			if (this.readyToWrite) {
-				obtainWriteSubscriber().onComplete();
+				requiredWriteSubscriber().onComplete();
 				return;
 			}
 			synchronized (this) {
 				if (this.readyToWrite) {
-					obtainWriteSubscriber().onComplete();
+					requiredWriteSubscriber().onComplete();
 				}
 				else if (this.beforeFirstEmission) {
 					this.completed = true;
 					this.beforeFirstEmission = false;
-					writeFunction.apply(this).subscribe(new DownstreamBridge(subscriber));
+					writeFunction.apply(this).subscribe(new DownstreamBridge(this.completionSubscriber));
 				}
 				else {
 					this.completed = true;
@@ -151,16 +157,16 @@ public class ChannelSendOperator<T> extends Mono<Void> implements Scannable {
 		@Override
 		public final void onError(Throwable ex) {
 			if (this.readyToWrite) {
-				obtainWriteSubscriber().onError(ex);
+				requiredWriteSubscriber().onError(ex);
 				return;
 			}
 			synchronized (this) {
 				if (this.readyToWrite) {
-					obtainWriteSubscriber().onError(ex);
+					requiredWriteSubscriber().onError(ex);
 				}
 				else if (this.beforeFirstEmission) {
 					this.beforeFirstEmission = false;
-					subscriber.onError(ex);
+					this.completionSubscriber.onError(ex);
 				}
 				else {
 					this.error = ex;
@@ -171,24 +177,24 @@ public class ChannelSendOperator<T> extends Mono<Void> implements Scannable {
 		@Override
 		public final void onNext(T item) {
 			if (this.readyToWrite) {
-				obtainWriteSubscriber().onNext(item);
+				requiredWriteSubscriber().onNext(item);
 				return;
 			}
 			//FIXME revisit in case of reentrant sync deadlock
 			synchronized (this) {
 				if (this.readyToWrite) {
-					obtainWriteSubscriber().onNext(item);
+					requiredWriteSubscriber().onNext(item);
 				}
 				else if (this.beforeFirstEmission) {
 					this.item = item;
 					this.beforeFirstEmission = false;
-					writeFunction.apply(this).subscribe(new DownstreamBridge(subscriber));
+					writeFunction.apply(this).subscribe(new DownstreamBridge(this.completionSubscriber));
 				}
 				else {
 					if (this.subscription != null) {
 						this.subscription.cancel();
 					}
-					subscriber.onError(new IllegalStateException("Unexpected item."));
+					this.completionSubscriber.onError(new IllegalStateException("Unexpected item."));
 				}
 			}
 		}
@@ -197,8 +203,8 @@ public class ChannelSendOperator<T> extends Mono<Void> implements Scannable {
 		public final void onSubscribe(Subscription s) {
 			if (Operators.validate(this.subscription, s)) {
 				this.subscription = s;
-				this.subscriber.onSubscribe(this);
-				s.request(1);  // bypass doRequest
+				this.completionSubscriber.onSubscribe(this);
+				s.request(1);
 			}
 		}
 
@@ -223,14 +229,14 @@ public class ChannelSendOperator<T> extends Mono<Void> implements Scannable {
 		 */
 		private boolean emitCachedSignals() {
 			if (this.item != null) {
-				obtainWriteSubscriber().onNext(this.item);
+				requiredWriteSubscriber().onNext(this.item);
 			}
 			if (this.error != null) {
-				obtainWriteSubscriber().onError(this.error);
+				requiredWriteSubscriber().onError(this.error);
 				return true;
 			}
 			if (this.completed) {
-				obtainWriteSubscriber().onComplete();
+				requiredWriteSubscriber().onComplete();
 				return true;
 			}
 			return false;
@@ -242,13 +248,13 @@ public class ChannelSendOperator<T> extends Mono<Void> implements Scannable {
 			if (s == null) {
 				return;
 			}
-			if (readyToWrite) {
+			if (this.readyToWrite) {
 				s.request(n);
 				return;
 			}
 			synchronized (this) {
 				if (this.writeSubscriber != null) {
-					readyToWrite = true;
+					this.readyToWrite = true;
 					if (emitCachedSignals()) {
 						return;
 					}
@@ -261,7 +267,7 @@ public class ChannelSendOperator<T> extends Mono<Void> implements Scannable {
 			s.request(n);
 		}
 
-		private Subscriber<? super T> obtainWriteSubscriber() {
+		private Subscriber<? super T> requiredWriteSubscriber() {
 			Assert.state(this.writeSubscriber != null, "No write subscriber");
 			return this.writeSubscriber;
 		}
@@ -297,7 +303,7 @@ public class ChannelSendOperator<T> extends Mono<Void> implements Scannable {
 
 		@Override
 		public Context currentContext() {
-			return downstream.currentContext();
+			return this.downstream.currentContext();
 		}
 	}