Deprecating RxJava components in the reactive module

Resolves #1317
Resolves #1320

spring-cloud-stream-reactive/src/main/java/org/springframework/cloud/stream/reactive/MessageChannelToInputObservableParameterAdapter.java

@@ -28,6 +28,9 @@ import org.springframework.util.Assert;
 /**
  * Adapts an {@link org.springframework.cloud.stream.annotation.Input} annotated
  * {@link MessageChannel} to an {@link Observable}.
+ *
+ * @deprecated as of 2.0.0.RELEASE, this is deprecated and will be removed in 2.1 Use Project Reactor based alternatives offered in Spring Cloud Stream.
+ *
  * @author Marius Bogoevici
  */
 public class MessageChannelToInputObservableParameterAdapter

spring-cloud-stream-reactive/src/main/java/org/springframework/cloud/stream/reactive/MessageChannelToObservableSenderParameterAdapter.java

@@ -31,8 +31,12 @@ import org.springframework.util.Assert;
 /**
  * Adapts an {@link org.springframework.cloud.stream.annotation.Output} annotated
  * {@link ObservableSender} to an outbound {@link MessageChannel}.
+ *
+ * @deprecated as of 2.0.0.RELEASE, this is deprecated and will be removed in 2.1 Use Project Reactor based alternatives offered in Spring Cloud Stream.
+ *
  * @author Marius Bogoevici
  */
+@Deprecated
 public class MessageChannelToObservableSenderParameterAdapter implements
 		StreamListenerParameterAdapter<ObservableSender, MessageChannel> {
 

spring-cloud-stream-reactive/src/main/java/org/springframework/cloud/stream/reactive/ObservableSender.java

@@ -23,8 +23,11 @@ import rx.Single;
  * Used for {@link org.springframework.cloud.stream.annotation.StreamListener} arguments
  * annotated with {@link org.springframework.cloud.stream.annotation.Output}.
  *
+ * @deprecated as of 2.0.0.RELEASE, this interface is deprecated and will be removed in 2.1 Use Project Reactor based {@link FluxSender}.
+ *
  * @author Marius Bogoevici
  */
+@Deprecated
 public interface ObservableSender {
 
 	/**

spring-cloud-stream-reactive/src/main/java/org/springframework/cloud/stream/reactive/ObservableToMessageChannelResultAdapter.java

@@ -31,7 +31,9 @@ import org.springframework.util.Assert;
  * {@link MessageChannel}.
  *
  * @author Marius Bogoevici
+ * @deprecated as of 2.0.0.RELEASE, this is deprecated and will be removed in 2.1 Use Project Reactor based alternatives offered in Spring Cloud Stream.
  */
+@Deprecated
 public class ObservableToMessageChannelResultAdapter
 		implements StreamListenerResultAdapter<Observable<?>, MessageChannel> {