Properly mention Apache Kafka trademark in docs (#3540)

Author: artembilan

spring-integration-kafka/src/main/java/org/springframework/integration/kafka/channel/AbstractKafkaChannel.java

@@ -28,9 +28,10 @@
 import org.springframework.util.Assert;
 
 /**
- * Abstract MessageChannel backed by a Kafka topic.
+ * Abstract MessageChannel backed by an Apache Kafka topic.
  *
  * @author Gary Russell
+ * @author Artem Bilan
  *
  * @since 5.4
  *
@@ -44,7 +45,7 @@ public abstract class AbstractKafkaChannel extends AbstractMessageChannel {
 	private String groupId;
 
 	/**
-	 * Construct an instance with the provided paramters.
+	 * Construct an instance with the provided {@link KafkaOperations} and topic.
 	 * @param template the template.
 	 * @param topic the topic.
 	 */

spring-integration-kafka/src/main/java/org/springframework/integration/kafka/channel/PollableKafkaChannel.java

@@ -33,7 +33,7 @@
 import org.springframework.util.Assert;
 
 /**
- * Pollable channel backed by a Kafka topic.
+ * Pollable channel backed by an Apache Kafka topic.
  *
  * @author Gary Russell
  * @author Artem Bilan
@@ -64,13 +64,6 @@ public PollableKafkaChannel(KafkaOperations<?, ?> template, KafkaMessageSource<?
 		}
 	}
 
-	private static String topic(KafkaMessageSource<?, ?> source) {
-		Assert.notNull(source, "'source' cannot be null");
-		String[] topics = source.getConsumerProperties().getTopics();
-		Assert.isTrue(topics != null && topics.length == 1, "Only one topic is allowed");
-		return topics[0];
-	}
-
 	@Override
 	@Nullable
 	public Message<?> receive() {
@@ -88,10 +81,9 @@ protected Message<?> doReceive() {
 		ChannelInterceptorList interceptorList = getIChannelInterceptorList();
 		Deque<ChannelInterceptor> interceptorStack = null;
 		boolean counted = false;
-		boolean traceEnabled = isLoggingEnabled() && logger.isTraceEnabled();
 		try {
-			if (traceEnabled) {
-				logger.trace("preReceive on channel '" + this + "'");
+			if (isLoggingEnabled()) {
+				logger.trace(() -> "preReceive on channel '" + this + "'");
 			}
 			if (interceptorList.getInterceptors().size() > 0) {
 				interceptorStack = new ArrayDeque<>();
@@ -197,4 +189,11 @@ public boolean hasExecutorInterceptors() {
 		return this.executorInterceptorsSize > 0;
 	}
 
+	private static String topic(KafkaMessageSource<?, ?> source) {
+		Assert.notNull(source, "'source' cannot be null");
+		String[] topics = source.getConsumerProperties().getTopics();
+		Assert.isTrue(topics != null && topics.length == 1, "Only one topic is allowed");
+		return topics[0];
+	}
+
 }

spring-integration-kafka/src/main/java/org/springframework/integration/kafka/channel/PublishSubscribeKafkaChannel.java

@@ -23,7 +23,7 @@
 import org.springframework.kafka.core.KafkaOperations;
 
 /**
- * Publish/subscribe channel backed by a Kafka topic.
+ * Publish/subscribe channel backed by an Apache Kafka topic.
  *
  * @author Gary Russell
  *

spring-integration-kafka/src/main/java/org/springframework/integration/kafka/channel/SubscribableKafkaChannel.java

@@ -34,7 +34,7 @@
 import org.springframework.util.Assert;
 
 /**
- * Subscribable channel backed by a Kafka topic.
+ * Subscribable channel backed by an Apache Kafka topic.
  *
  * @author Gary Russell
  * @author Artem Bilan

spring-integration-kafka/src/main/java/org/springframework/integration/kafka/channel/package-info.java

@@ -1,4 +1,4 @@
 /**
- * Provides classes related to message channels.
+ * Provides classes related to message channel implementations for Apache Kafka.
  */
 package org.springframework.integration.kafka.channel;

spring-integration-kafka/src/main/java/org/springframework/integration/kafka/config/xml/KafkaChannelParser.java

@@ -28,7 +28,7 @@
 import org.springframework.util.StringUtils;
 
 /**
- * Parser for a channel backed by a Kafka topic.
+ * Parser for a channel backed by an Apache Kafka topic.
  *
  * @author Gary Russell
  *

spring-integration-kafka/src/main/java/org/springframework/integration/kafka/config/xml/KafkaNamespaceHandler.java

@@ -19,7 +19,7 @@
 import org.springframework.integration.config.xml.AbstractIntegrationNamespaceHandler;
 
 /**
- * The namespace handler for the Kafka namespace.
+ * The namespace handler for the Apache Kafka namespace.
  *
  * @author Soby Chacko
  * @author Gary Russell

spring-integration-kafka/src/main/java/org/springframework/integration/kafka/config/xml/package-info.java

@@ -1,4 +1,4 @@
 /**
- * Provides parser classes to provide Xml namespace support for the Kafka components.
+ * Provides parser classes to provide Xml namespace support for the Apache Kafka components.
  */
 package org.springframework.integration.kafka.config.xml;

spring-integration-kafka/src/main/java/org/springframework/integration/kafka/dsl/AbstractKafkaChannelSpec.java

@@ -21,7 +21,7 @@
 
 /**
  *
- * Spec for a message channel backed by a Kafka topic.
+ * Spec for a message channel backed by an Apache Kafka topic.
  *
  * @param <S> the spec type.
  * @param <C> the channel type.

spring-integration-kafka/src/main/java/org/springframework/integration/kafka/dsl/Kafka.java

@@ -143,7 +143,8 @@ public static <K, V> KafkaInboundChannelAdapterSpec<K, V> inboundChannelAdapter(
 			KafkaAckCallbackFactory<K, V> ackCallbackFactory,
 			boolean allowMultiFetch) {
 
-		return new KafkaInboundChannelAdapterSpec<>(consumerFactory, consumerProperties, ackCallbackFactory, allowMultiFetch);
+		return new KafkaInboundChannelAdapterSpec<>(consumerFactory, consumerProperties, ackCallbackFactory,
+				allowMultiFetch);
 	}
 
 	/**