TaskExecutorRegistration does not apply its default settings to a user-provided executor

Also, ChannelRegistration.setInterceptors is deprecated now: in favor of a fluently named interceptors(...) method which is documented to add the given interceptors to the channel's current list.

Issue: SPR-15962
Issue: SPR-15976

spring-messaging/src/main/java/org/springframework/messaging/simp/config/AbstractMessageBrokerConfiguration.java

@@ -126,13 +126,15 @@ public abstract class AbstractMessageBrokerConfiguration implements ApplicationC
 	public AbstractSubscribableChannel clientInboundChannel() {
 		ExecutorSubscribableChannel channel = new ExecutorSubscribableChannel(clientInboundChannelExecutor());
 		ChannelRegistration reg = getClientInboundChannelRegistration();
-		channel.setInterceptors(reg.getInterceptors());
+		if (reg.hasInterceptors()) {
+			channel.setInterceptors(reg.getInterceptors());
+		}
 		return channel;
 	}
 
 	@Bean
 	public ThreadPoolTaskExecutor clientInboundChannelExecutor() {
-		TaskExecutorRegistration reg = getClientInboundChannelRegistration().getOrCreateTaskExecRegistration();
+		TaskExecutorRegistration reg = getClientInboundChannelRegistration().taskExecutor();
 		ThreadPoolTaskExecutor executor = reg.getTaskExecutor();
 		executor.setThreadNamePrefix("clientInboundChannel-");
 		return executor;
@@ -142,7 +144,7 @@ public abstract class AbstractMessageBrokerConfiguration implements ApplicationC
 		if (this.clientInboundChannelRegistration == null) {
 			ChannelRegistration registration = new ChannelRegistration();
 			configureClientInboundChannel(registration);
-			registration.setInterceptors(new ImmutableMessageChannelInterceptor());
+			registration.interceptors(new ImmutableMessageChannelInterceptor());
 			this.clientInboundChannelRegistration = registration;
 		}
 		return this.clientInboundChannelRegistration;
@@ -159,13 +161,15 @@ public abstract class AbstractMessageBrokerConfiguration implements ApplicationC
 	public AbstractSubscribableChannel clientOutboundChannel() {
 		ExecutorSubscribableChannel channel = new ExecutorSubscribableChannel(clientOutboundChannelExecutor());
 		ChannelRegistration reg = getClientOutboundChannelRegistration();
-		channel.setInterceptors(reg.getInterceptors());
+		if (reg.hasInterceptors()) {
+			channel.setInterceptors(reg.getInterceptors());
+		}
 		return channel;
 	}
 
 	@Bean
 	public ThreadPoolTaskExecutor clientOutboundChannelExecutor() {
-		TaskExecutorRegistration reg = getClientOutboundChannelRegistration().getOrCreateTaskExecRegistration();
+		TaskExecutorRegistration reg = getClientOutboundChannelRegistration().taskExecutor();
 		ThreadPoolTaskExecutor executor = reg.getTaskExecutor();
 		executor.setThreadNamePrefix("clientOutboundChannel-");
 		return executor;
@@ -175,7 +179,7 @@ public abstract class AbstractMessageBrokerConfiguration implements ApplicationC
 		if (this.clientOutboundChannelRegistration == null) {
 			ChannelRegistration registration = new ChannelRegistration();
 			configureClientOutboundChannel(registration);
-			registration.setInterceptors(new ImmutableMessageChannelInterceptor());
+			registration.interceptors(new ImmutableMessageChannelInterceptor());
 			this.clientOutboundChannelRegistration = registration;
 		}
 		return this.clientOutboundChannelRegistration;
@@ -191,9 +195,9 @@ public abstract class AbstractMessageBrokerConfiguration implements ApplicationC
 	@Bean
 	public AbstractSubscribableChannel brokerChannel() {
 		ChannelRegistration reg = getBrokerRegistry().getBrokerChannelRegistration();
-		ExecutorSubscribableChannel channel = reg.hasTaskExecutor() ?
+		ExecutorSubscribableChannel channel = (reg.hasTaskExecutor() ?
-				new ExecutorSubscribableChannel(brokerChannelExecutor()) : new ExecutorSubscribableChannel();
+				new ExecutorSubscribableChannel(brokerChannelExecutor()) : new ExecutorSubscribableChannel());
-		reg.setInterceptors(new ImmutableMessageChannelInterceptor());
+		reg.interceptors(new ImmutableMessageChannelInterceptor());
 		channel.setInterceptors(reg.getInterceptors());
 		return channel;
 	}

spring-messaging/src/main/java/org/springframework/messaging/simp/config/ChannelRegistration.java

@@ -43,43 +43,43 @@ public class ChannelRegistration {
 	 * Configure the thread pool backing this message channel.
 	 */
 	public TaskExecutorRegistration taskExecutor() {
-		if (this.registration == null) {
+		return taskExecutor(null);
-			this.registration = new TaskExecutorRegistration();
-		}
-		return this.registration;
 	}
 
 	/**
 	 * Configure the thread pool backing this message channel using a custom
 	 * ThreadPoolTaskExecutor.
+	 * @param taskExecutor the executor to use (or {@code null} for a default executor)
 	 */
-	public TaskExecutorRegistration taskExecutor(ThreadPoolTaskExecutor taskExecutor) {
+	public TaskExecutorRegistration taskExecutor(@Nullable ThreadPoolTaskExecutor taskExecutor) {
 		if (this.registration == null) {
-			this.registration = new TaskExecutorRegistration(taskExecutor);
+			this.registration = (taskExecutor != null ? new TaskExecutorRegistration(taskExecutor) :
+					new TaskExecutorRegistration());
 		}
 		return this.registration;
 	}
 
 	/**
-	 * Configure interceptors for the message channel.
+	 * Configure the given interceptors for this message channel,
+	 * adding them to the channel's current list of interceptors.
+	 * @since 4.3.12
 	 */
-	public ChannelRegistration setInterceptors(ChannelInterceptor... interceptors) {
+	public ChannelRegistration interceptors(ChannelInterceptor... interceptors) {
 		this.interceptors.addAll(Arrays.asList(interceptors));
 		return this;
 	}
 
-
+	/**
-	protected boolean hasTaskExecutor() {
+	 * @deprecated as of 4.3.12, in favor of {@link #interceptors(ChannelInterceptor...)}
-		return (this.registration != null);
+	 */
+	@Deprecated
+	public ChannelRegistration setInterceptors(ChannelInterceptor... interceptors) {
+		return interceptors(interceptors);
 	}
 
-	@Nullable
-	protected TaskExecutorRegistration getTaskExecRegistration() {
-		return this.registration;
-	}
 
-	protected TaskExecutorRegistration getOrCreateTaskExecRegistration() {
+	protected boolean hasTaskExecutor() {
-		return taskExecutor();
+		return (this.registration != null);
 	}
 
 	protected boolean hasInterceptors() {
@@ -89,4 +89,5 @@ public class ChannelRegistration {
 	protected List<ChannelInterceptor> getInterceptors() {
 		return this.interceptors;
 	}
+
 }

spring-messaging/src/main/java/org/springframework/messaging/simp/config/TaskExecutorRegistration.java

@@ -18,34 +18,53 @@ package org.springframework.messaging.simp.config;
 
 import org.springframework.lang.Nullable;
 import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;
+import org.springframework.util.Assert;
 
 /**
  * A registration class for customizing the properties of {@link ThreadPoolTaskExecutor}.
  *
  * @author Rossen Stoyanchev
+ * @author Juergen Hoeller
  * @since 4.0
  */
 public class TaskExecutorRegistration {
 
-	@Nullable
+	private final ThreadPoolTaskExecutor taskExecutor;
-	private ThreadPoolTaskExecutor taskExecutor;
 
-	private int corePoolSize = Runtime.getRuntime().availableProcessors() * 2;
+	@Nullable
+	private Integer corePoolSize;
 
-	private int maxPoolSize = Integer.MAX_VALUE;
+	@Nullable
+	private Integer maxPoolSize;
 
-	private int queueCapacity = Integer.MAX_VALUE;
+	@Nullable
+	private Integer keepAliveSeconds;
 
-	private int keepAliveSeconds = 60;
+	@Nullable
+	private Integer queueCapacity;
 
 
+	/**
+	 * Create a new {@code TaskExecutorRegistration} for a default
+	 * {@link ThreadPoolTaskExecutor}.
+	 */
 	public TaskExecutorRegistration() {
+		this.taskExecutor = new ThreadPoolTaskExecutor();
+		this.taskExecutor.setCorePoolSize(Runtime.getRuntime().availableProcessors() * 2);
+		this.taskExecutor.setAllowCoreThreadTimeOut(true);
 	}
 
+	/**
+	 * Create a new {@code TaskExecutorRegistration} for a given
+	 * {@link ThreadPoolTaskExecutor}.
+	 * @param taskExecutor the executor to use
+	 */
 	public TaskExecutorRegistration(ThreadPoolTaskExecutor taskExecutor) {
+		Assert.notNull(taskExecutor, "ThreadPoolTaskExecutor must not be null");
 		this.taskExecutor = taskExecutor;
 	}
 
+
 	/**
 	 * Set the core pool size of the ThreadPoolExecutor.
 	 * <p><strong>NOTE:</strong> The core pool size is effectively the max pool size
@@ -77,6 +96,18 @@ public class TaskExecutorRegistration {
 		return this;
 	}
 
+	/**
+	 * Set the time limit for which threads may remain idle before being terminated.
+	 * If there are more than the core number of threads currently in the pool,
+	 * after waiting this amount of time without processing a task, excess threads
+	 * will be terminated. This overrides any value set in the constructor.
+	 * <p>By default this is set to 60.
+	 */
+	public TaskExecutorRegistration keepAliveSeconds(int keepAliveSeconds) {
+		this.keepAliveSeconds = keepAliveSeconds;
+		return this;
+	}
+
 	/**
 	 * Set the queue capacity for the ThreadPoolExecutor.
 	 * <p><strong>NOTE:</strong> when an unbounded {@code queueCapacity} is configured
@@ -91,26 +122,21 @@ public class TaskExecutorRegistration {
 		return this;
 	}
 
-	/**
-	 * Set the time limit for which threads may remain idle before being terminated.
-	 * If there are more than the core number of threads currently in the pool,
-	 * after waiting this amount of time without processing a task, excess threads
-	 * will be terminated. This overrides any value set in the constructor.
-	 * <p>By default this is set to 60.
-	 */
-	public TaskExecutorRegistration keepAliveSeconds(int keepAliveSeconds) {
-		this.keepAliveSeconds = keepAliveSeconds;
-		return this;
-	}
 
 	protected ThreadPoolTaskExecutor getTaskExecutor() {
-		ThreadPoolTaskExecutor executor = (this.taskExecutor != null ? this.taskExecutor : new ThreadPoolTaskExecutor());
+		if (this.corePoolSize != null) {
-		executor.setCorePoolSize(this.corePoolSize);
+			this.taskExecutor.setCorePoolSize(this.corePoolSize);
-		executor.setMaxPoolSize(this.maxPoolSize);
+		}
-		executor.setKeepAliveSeconds(this.keepAliveSeconds);
+		if (this.maxPoolSize != null) {
-		executor.setQueueCapacity(this.queueCapacity);
+			this.taskExecutor.setMaxPoolSize(this.maxPoolSize);
-		executor.setAllowCoreThreadTimeOut(true);
+		}
-		return executor;
+		if (this.keepAliveSeconds != null) {
+			this.taskExecutor.setKeepAliveSeconds(this.keepAliveSeconds);
+		}
+		if (this.queueCapacity != null) {
+			this.taskExecutor.setQueueCapacity(this.queueCapacity);
+		}
+		return this.taskExecutor;
 	}
 
 }

spring-messaging/src/test/java/org/springframework/messaging/simp/config/MessageBrokerConfigurationTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2017 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.
@@ -512,14 +512,14 @@ public class MessageBrokerConfigurationTests {
 
 		@Override
 		protected void configureClientInboundChannel(ChannelRegistration registration) {
-			registration.setInterceptors(this.interceptor);
+			registration.interceptors(this.interceptor);
 			registration.taskExecutor(new CustomThreadPoolTaskExecutor())
 					.corePoolSize(11).maxPoolSize(12).keepAliveSeconds(13).queueCapacity(14);
 		}
 
 		@Override
 		protected void configureClientOutboundChannel(ChannelRegistration registration) {
-			registration.setInterceptors(this.interceptor, this.interceptor);
+			registration.interceptors(this.interceptor, this.interceptor);
 			registration.taskExecutor().corePoolSize(21).maxPoolSize(22).keepAliveSeconds(23).queueCapacity(24);
 		}
 
@@ -535,7 +535,7 @@ public class MessageBrokerConfigurationTests {
 
 		@Override
 		protected void configureMessageBroker(MessageBrokerRegistry registry) {
-			registry.configureBrokerChannel().setInterceptors(this.interceptor, this.interceptor, this.interceptor);
+			registry.configureBrokerChannel().interceptors(this.interceptor, this.interceptor, this.interceptor);
 			registry.configureBrokerChannel().taskExecutor().corePoolSize(31).maxPoolSize(32).keepAliveSeconds(33).queueCapacity(34);
 			registry.setPathMatcher(new AntPathMatcher(".")).enableSimpleBroker("/topic", "/queue");
 			registry.setCacheLimit(8192);