Upgrade to reactor 1.0 RC1 and remove MessageChannel

This change upgrades reactor to 1.0 RC1 and also removes the
reactor-based message channel in favor of the one available from
org.projectreactor:reactor-spring.

spring-messaging/src/main/java/org/springframework/messaging/support/channel/AbstractSubscribableChannel.java

@@ -41,8 +41,14 @@ public abstract class AbstractSubscribableChannel extends AbstractMessageChannel
 		return subscribeInternal(handler);
 	}
 
+	/**
+	 * Whether the given {@link MessageHandler} is already subscribed.
+	 */
 	protected abstract boolean hasSubscription(MessageHandler handler);
 
+	/**
+	 * Subscribe the given {@link MessageHandler}.
+	 */
 	protected abstract boolean subscribeInternal(MessageHandler handler);
 
 	@Override
@@ -53,6 +59,9 @@ public abstract class AbstractSubscribableChannel extends AbstractMessageChannel
 		return unsubscribeInternal(handler);
 	}
 
+	/**
+	 * Unsubscribe the given {@link MessageHandler}.
+	 */
 	protected abstract boolean unsubscribeInternal(MessageHandler handler);
 
 }

spring-messaging/src/main/java/org/springframework/messaging/support/channel/ReactorSubscribableChannel.java

@@ -1,101 +0,0 @@
-/*
- * Copyright 2002-2013 the original author or authors.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.springframework.messaging.support.channel;
-
-import java.util.HashMap;
-import java.util.Map;
-
-import org.springframework.messaging.Message;
-import org.springframework.messaging.MessageHandler;
-
-import reactor.core.Reactor;
-import reactor.event.Event;
-import reactor.event.registry.Registration;
-import reactor.event.selector.ObjectSelector;
-import reactor.event.selector.Selector;
-import reactor.function.Consumer;
-
-
-/**
- * @author Rossen Stoyanchev
- * @since 4.0
- */
-public class ReactorSubscribableChannel extends AbstractSubscribableChannel {
-
-	private final Reactor reactor;
-
-	private final Object key = new Object();
-
-	private final Map<MessageHandler, Registration<?>> registrations = new HashMap<MessageHandler, Registration<?>>();
-
-
-	public ReactorSubscribableChannel(Reactor reactor) {
-		this.reactor = reactor;
-	}
-
-
-	@Override
-	protected boolean hasSubscription(MessageHandler handler) {
-		return this.registrations.containsKey(handler);
-	}
-
-	@Override
-	public boolean sendInternal(Message<?> message, long timeout) {
-		this.reactor.notify(this.key, Event.wrap(message));
-		return true;
-	}
-
-	@Override
-	public boolean subscribeInternal(final MessageHandler handler) {
-		Selector selector = ObjectSelector.objectSelector(this.key);
-		MessageHandlerConsumer consumer = new MessageHandlerConsumer(handler);
-		Registration<Consumer<Event<Message<?>>>> registration = this.reactor.on(selector, consumer);
-		this.registrations.put(handler, registration);
-		return true;
-	}
-
-	@Override
-	public boolean unsubscribeInternal(MessageHandler handler) {
-		Registration<?> registration = this.registrations.remove(handler);
-		if (registration != null) {
-			registration.cancel();
-			return true;
-		}
-		return false;
-	}
-
-
-	private final class MessageHandlerConsumer implements Consumer<Event<Message<?>>> {
-
-		private final MessageHandler handler;
-
-		private MessageHandlerConsumer(MessageHandler handler) {
-			this.handler = handler;
-		}
-
-		@Override
-		public void accept(Event<Message<?>> event) {
-			Message<?> message = event.getData();
-			try {
-				this.handler.handleMessage(message);
-			}
-			catch (Throwable t) {
-				logger.error("Failed to process message " + message, t);
-			}
-		}
-	}
-}