Add documentation to configurations

Revise integrationFlow to be idiomatic of the Kotlin DSL

Author: cppwfs

basic/helloworld-kotlin/src/main/kotlin/org/springframework/integration/samples/helloworld/HelloWorldConfig.kt

@@ -21,7 +21,6 @@ import org.springframework.context.annotation.Configuration
 import org.springframework.integration.channel.DirectChannel
 import org.springframework.integration.channel.QueueChannel
 import org.springframework.integration.config.EnableIntegration
-import org.springframework.integration.dsl.IntegrationFlow
 import org.springframework.integration.dsl.integrationFlow
 import org.springframework.messaging.MessageChannel
 
@@ -30,24 +29,57 @@ import org.springframework.messaging.MessageChannel
  *
  * @author Glenn Renfro
  */
-@Configuration
+@Configuration(proxyBeanMethods = false)
 @EnableIntegration
 open class HelloWorldConfig {
 
+    /**
+     * Creates the input channel for inbound messages.
+     *
+     * A [DirectChannel] is used for synchronous, immediate message delivery.
+     * Messages arriving on this channel are processed on the sender's thread
+     * without any buffering or queuing.
+     *
+     * @return A [DirectChannel] instance for synchronous inbound message delivery
+     */
     @Bean
     open fun inputChannel() = DirectChannel()
 
+    /**
+     * Creates the output channel for outbound messages.
+     *
+     * A [QueueChannel] with capacity of 10 messages provides asynchronous,
+     * buffered message delivery. Results from the integration flow are queued
+     * and available for downstream consumption.
+     *
+     * @return A [QueueChannel] instance with capacity of 10 messages
+     */
     @Bean
     open fun outputChannel() = QueueChannel(10)
 
+    /**
+     * Creates the Hello World business service.
+     *
+     * [HelloService] implements the core greeting logic that transforms
+     * input messages into personalized greeting responses.
+     *
+     * @return A [HelloService] instance
+     */
     @Bean
     open fun helloService() = HelloService()
 
+    /**
+     * Defines the main integration flow for message processing.
+     *
+     * @param inputChannel The synchronous input channel receiving messages
+     * @param outputChannel The asynchronous output channel for results
+     * @param helloService The service implementing the greeting logic
+     * @return An IntegrationFlow representing the complete message flow
+     */
     @Bean
-    open fun helloWorldFlow(inputChannel: MessageChannel,
-                            outputChannel: MessageChannel) = integrationFlow(inputChannel) {
-            handle(helloService(), "sayHello")
+    open fun helloWorldFlow(inputChannel: MessageChannel, outputChannel: MessageChannel, helloService: HelloService) =
+        integrationFlow(inputChannel) {
+            handle(helloService, "sayHello")
             channel(outputChannel)
         }
-
 }

basic/helloworld-kotlin/src/main/kotlin/org/springframework/integration/samples/helloworld/PollerConfig.kt

@@ -18,8 +18,10 @@ package org.springframework.integration.samples.helloworld
 
 import org.springframework.context.annotation.Bean
 import org.springframework.context.annotation.Configuration
+import org.springframework.integration.channel.NullChannel
 import org.springframework.integration.config.EnableIntegration
-import org.springframework.integration.dsl.IntegrationFlow
+import org.springframework.integration.dsl.integrationFlow
+import org.springframework.integration.endpoint.MessageProcessorMessageSource
 import org.springframework.integration.handler.LoggingHandler
 
 /**
@@ -28,17 +30,26 @@ import org.springframework.integration.handler.LoggingHandler
  *
  * @author Glenn Renfro
  */
-@Configuration
+@Configuration(proxyBeanMethods = false)
 @EnableIntegration
 open class PollerConfig {
 
+    /**
+     * Defines a polling-based integration flow for periodic message generation.
+     *
+     * This flow demonstrates a time-triggered, scheduled message processing pattern.
+     * A message source generates timestamps at fixed intervals, logs the values,
+     * and discards them via the null channel. This is useful for monitoring,
+     * health checks, or triggering periodic processing logic.
+     *
+     * @return An IntegrationFlow that periodically generates and logs timestamps, then discards them.
+     */
     @Bean
     open fun pollerFlow() =
-        IntegrationFlow.fromSupplier({ System.currentTimeMillis() }) { e ->
-            e.poller { p ->
-                p.fixedDelay(20000).maxMessagesPerPoll(2)
+        integrationFlow(
+            MessageProcessorMessageSource { System.currentTimeMillis() },
+                    { poller { it.fixedDelay(20000).maxMessagesPerPoll(2) } }) {
+                log(LoggingHandler.Level.INFO, "org.springframework.integration.samples.helloworld")
+                channel(NullChannel())
             }
-        }
-            .log(LoggingHandler.Level.INFO, "org.springframework.integration.samples.helloworld")
-            .nullChannel()
 }