Deprecate (Reactive)PulsarListenerEndpointAdapter (#481)

This commit deprecates PulsarListenerEndpointAdapter and 
ReactivePulsarListenerEndpointAdapter in favor of default methods on 
ListenerEndpoint and its sub-interfaces, which makes it a bit easier to
provide custom ListenerEndpoint implementations.

spring-pulsar-reactive/src/main/java/org/springframework/pulsar/reactive/config/DefaultReactivePulsarListenerContainerFactory.java

@@ -156,7 +156,7 @@ public class DefaultReactivePulsarListenerContainerFactory<T> implements Reactiv
 
 	@Override
 	public DefaultReactivePulsarMessageListenerContainer<T> createContainer(String... topics) {
-		ReactivePulsarListenerEndpoint<T> endpoint = new ReactivePulsarListenerEndpointAdapter<>() {
+		ReactivePulsarListenerEndpoint<T> endpoint = new ReactivePulsarListenerEndpoint<>() {
 
 			@Override
 			public List<String> getTopics() {

spring-pulsar-reactive/src/main/java/org/springframework/pulsar/reactive/config/ReactivePulsarListenerEndpoint.java

@@ -29,12 +29,17 @@ import org.springframework.pulsar.reactive.listener.ReactivePulsarMessageListene
  * @param <T> Message payload type.
  * @author Christophe Bornet
  * @author Chris Bono
+ * @author Vedran Pavic
  */
 public interface ReactivePulsarListenerEndpoint<T> extends ListenerEndpoint<ReactivePulsarMessageListenerContainer<T>> {
 
-	boolean isFluxListener();
+	default boolean isFluxListener() {
+		return false;
+	}
 
 	@Nullable
-	Boolean getUseKeyOrderedProcessing();
+	default Boolean getUseKeyOrderedProcessing() {
+		return null;
+	}
 
 }

spring-pulsar-reactive/src/main/java/org/springframework/pulsar/reactive/config/ReactivePulsarListenerEndpointAdapter.java

@@ -31,7 +31,9 @@ import org.springframework.pulsar.support.MessageConverter;
  *
  * @param <T> Message payload type.
  * @author Christophe Bornet
+ * @deprecated for removal in favor of {@link ReactivePulsarListenerEndpoint}
  */
+@Deprecated(forRemoval = true)
 public class ReactivePulsarListenerEndpointAdapter<T> implements ReactivePulsarListenerEndpoint<T> {
 
 	@Override

spring-pulsar/src/main/java/org/springframework/pulsar/config/ConcurrentPulsarListenerContainerFactory.java

@@ -54,7 +54,7 @@ public class ConcurrentPulsarListenerContainerFactory<T>
 
 	@Override
 	public ConcurrentPulsarMessageListenerContainer<T> createContainer(String... topics) {
-		PulsarListenerEndpoint endpoint = new PulsarListenerEndpointAdapter() {
+		PulsarListenerEndpoint endpoint = new PulsarListenerEndpoint() {
 
 			@Override
 			public Collection<String> getTopics() {

spring-pulsar/src/main/java/org/springframework/pulsar/config/ListenerEndpoint.java

@@ -17,6 +17,7 @@
 package org.springframework.pulsar.config;
 
 import java.util.Collection;
+import java.util.Collections;
 
 import org.apache.pulsar.client.api.SubscriptionType;
 import org.apache.pulsar.common.schema.SchemaType;
@@ -32,6 +33,7 @@ import org.springframework.pulsar.support.MessageConverter;
  *
  * @param <C> Message listener container type.
  * @author Christophe Bornet
+ * @author Vedran Pavic
  */
 public interface ListenerEndpoint<C extends MessageListenerContainer> {
 
@@ -42,53 +44,69 @@ public interface ListenerEndpoint<C extends MessageListenerContainer> {
 	 * @see ListenerContainerFactory#createListenerContainer
 	 */
 	@Nullable
-	String getId();
+	default String getId() {
+		return null;
+	}
 
 	/**
 	 * Return the subscription name for this endpoint's container.
 	 * @return the subscription name.
 	 */
 	@Nullable
-	String getSubscriptionName();
+	default String getSubscriptionName() {
+		return null;
+	}
 
 	/**
 	 * Return the subscription type for this endpoint's container.
 	 * @return the subscription type.
 	 */
 	@Nullable
-	SubscriptionType getSubscriptionType();
+	default SubscriptionType getSubscriptionType() {
+		return SubscriptionType.Exclusive;
+	}
 
 	/**
 	 * Return the topics for this endpoint's container.
 	 * @return the topics.
 	 */
-	Collection<String> getTopics();
+	default Collection<String> getTopics() {
+		return Collections.emptyList();
+	}
 
 	/**
 	 * Return the topic pattern for this endpoint's container.
 	 * @return the topic pattern.
 	 */
-	String getTopicPattern();
+	default String getTopicPattern() {
+		return null;
+	}
 
 	/**
 	 * Return the autoStartup for this endpoint's container.
 	 * @return the autoStartup.
 	 */
 	@Nullable
-	Boolean getAutoStartup();
+	default Boolean getAutoStartup() {
+		return null;
+	}
 
 	/**
 	 * Return the schema type for this endpoint's container.
 	 * @return the schema type.
 	 */
-	SchemaType getSchemaType();
+	default SchemaType getSchemaType() {
+		return null;
+	}
 
 	/**
 	 * Return the concurrency for this endpoint's container.
 	 * @return the concurrency.
 	 */
 	@Nullable
-	Integer getConcurrency();
+	default Integer getConcurrency() {
+		return null;
+	}
 
 	/**
 	 * Setup the specified message listener container with the model defined by this
@@ -101,6 +119,7 @@ public interface ListenerEndpoint<C extends MessageListenerContainer> {
 	 * @param listenerContainer the listener container to configure
 	 * @param messageConverter the message converter - can be null
 	 */
-	void setupListenerContainer(C listenerContainer, @Nullable MessageConverter messageConverter);
+	default void setupListenerContainer(C listenerContainer, @Nullable MessageConverter messageConverter) {
+	}
 
 }

spring-pulsar/src/main/java/org/springframework/pulsar/config/PulsarListenerEndpoint.java

@@ -28,13 +28,20 @@ import org.springframework.pulsar.listener.PulsarMessageListenerContainer;
  *
  * @author Soby Chacko
  * @author Alexander Preuß
+ * @author Vedran Pavic
  */
 public interface PulsarListenerEndpoint extends ListenerEndpoint<PulsarMessageListenerContainer> {
 
-	boolean isBatchListener();
+	default boolean isBatchListener() {
+		return false;
+	}
 
-	Properties getConsumerProperties();
+	default Properties getConsumerProperties() {
+		return null;
+	}
 
-	AckMode getAckMode();
+	default AckMode getAckMode() {
+		return null;
+	}
 
 }

spring-pulsar/src/main/java/org/springframework/pulsar/config/PulsarListenerEndpointAdapter.java

@@ -33,7 +33,9 @@ import org.springframework.pulsar.support.MessageConverter;
  *
  * @author Soby Chacko
  * @author Alexander Preuß
+ * @deprecated for removal in favor of {@link PulsarListenerEndpoint}
  */
+@Deprecated(forRemoval = true)
 public class PulsarListenerEndpointAdapter implements PulsarListenerEndpoint {
 
 	@Override