Fix issue with default executor for broker channel

The default for the broker channel should be "no executor".

Issue: SPR-11623

spring-websocket/src/main/java/org/springframework/web/socket/config/MessageBrokerBeanDefinitionParser.java

@@ -176,11 +176,15 @@ class MessageBrokerBeanDefinitionParser implements BeanDefinitionParser {
 			ParserContext parserCxt, Object source) {
 
 		RootBeanDefinition executorDef = null;
-		Element executor = null;
-
-		if (channelElement != null) {
-			executor = DomUtils.getChildElementByTagName(channelElement, "executor");
-			if (executor != null) {
+		if (channelElement == null) {
+			executorDef = getDefaultExecutorBeanDefinition(channelName);
+		}
+		else {
+			Element executor = DomUtils.getChildElementByTagName(channelElement, "executor");
+			if (executor == null) {
+				executorDef = getDefaultExecutorBeanDefinition(channelName);
+			}
+			else {
 				executorDef = new RootBeanDefinition(ThreadPoolTaskExecutor.class);
 				String attrValue = executor.getAttribute("core-pool-size");
 				if (!StringUtils.isEmpty(attrValue)) {
@@ -200,22 +204,16 @@ class MessageBrokerBeanDefinitionParser implements BeanDefinitionParser {
 				}
 			}
 		}
-		if ((channelElement == null && !channelName.equals("brokerChannel")) || (channelElement != null && executor == null)) {
-			executorDef = new RootBeanDefinition(ThreadPoolTaskExecutor.class);
-			executorDef.getPropertyValues().add("corePoolSize", Runtime.getRuntime().availableProcessors() * 2);
-			executorDef.getPropertyValues().add("maxPoolSize", Integer.MAX_VALUE);
-			executorDef.getPropertyValues().add("queueCapacity", Integer.MAX_VALUE);
-		}
 
-		ConstructorArgumentValues values = new ConstructorArgumentValues();
+		ConstructorArgumentValues argValues = new ConstructorArgumentValues();
 		if (executorDef != null) {
 			executorDef.getPropertyValues().add("threadNamePrefix", channelName + "-");
 			String executorName = channelName + "Executor";
 			registerBeanDefByName(executorName, executorDef, parserCxt, source);
-			values.addIndexedArgumentValue(0, new RuntimeBeanReference(executorName));
+			argValues.addIndexedArgumentValue(0, new RuntimeBeanReference(executorName));
 		}
 
-		RootBeanDefinition channelDef = new RootBeanDefinition(ExecutorSubscribableChannel.class, values, null);
+		RootBeanDefinition channelDef = new RootBeanDefinition(ExecutorSubscribableChannel.class, argValues, null);
 
 		if (channelElement != null) {
 			Element interceptorsElement = DomUtils.getChildElementByTagName(channelElement, "interceptors");
@@ -227,6 +225,17 @@ class MessageBrokerBeanDefinitionParser implements BeanDefinitionParser {
 		return new RuntimeBeanReference(channelName);
 	}
 
+	private RootBeanDefinition getDefaultExecutorBeanDefinition(String channelName) {
+		if (channelName.equals("brokerChannel")) {
+			return null;
+		}
+		RootBeanDefinition executorDef = new RootBeanDefinition(ThreadPoolTaskExecutor.class);
+		executorDef.getPropertyValues().add("corePoolSize", Runtime.getRuntime().availableProcessors() * 2);
+		executorDef.getPropertyValues().add("maxPoolSize", Integer.MAX_VALUE);
+		executorDef.getPropertyValues().add("queueCapacity", Integer.MAX_VALUE);
+		return executorDef;
+	}
+
 	private RuntimeBeanReference registerSubProtocolWebSocketHandler(Element element,
 			RuntimeBeanReference clientInChannel, RuntimeBeanReference clientOutChannel,
 			RuntimeBeanReference userSessionRegistry, ParserContext parserCxt, Object source) {

spring-websocket/src/test/java/org/springframework/web/socket/config/MessageBrokerBeanDefinitionParserTests.java

@@ -298,8 +298,10 @@ public class MessageBrokerBeanDefinitionParserTests {
 	@Test
 	public void customChannelsWithDefaultExecutor() {
 		loadBeanDefinitions("websocket-config-broker-customchannels-default-executor.xml");
-		List<Class<? extends MessageHandler>> subscriberTypes = Arrays.<Class<? extends MessageHandler>>asList(SubProtocolWebSocketHandler.class);
+
+		testExecutor("clientInboundChannel", Runtime.getRuntime().availableProcessors() * 2, Integer.MAX_VALUE, 60);
 		testExecutor("clientOutboundChannel", Runtime.getRuntime().availableProcessors() * 2, Integer.MAX_VALUE, 60);
+		assertFalse(this.appContext.containsBean("brokerChannelExecutor"));
 	}
 
 	@Test

spring-websocket/src/test/resources/org/springframework/web/socket/config/websocket-config-broker-customchannels-default-executor.xml

 <beans xmlns="http://www.springframework.org/schema/beans"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xmlns:websocket="http://www.springframework.org/schema/websocket"
-       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
+       xsi:schemaLocation="
+        http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
 		http://www.springframework.org/schema/websocket http://www.springframework.org/schema/websocket/spring-websocket-4.0.xsd">
 
     <websocket:message-broker>
-        <websocket:stomp-endpoint path="/foo,/bar">
-            <websocket:handshake-handler ref="myHandler"/>
-        </websocket:stomp-endpoint>
+        <websocket:stomp-endpoint path="/foo"/>
         <websocket:simple-broker prefix="/topic"/>
         <websocket:client-inbound-channel>
-            <websocket:executor core-pool-size="100" max-pool-size="200" keep-alive-seconds="600"/>
             <websocket:interceptors>
                 <ref bean="myInterceptor"/>
             </websocket:interceptors>
@@ -18,13 +16,15 @@
         <websocket:client-outbound-channel>
             <websocket:interceptors>
                 <ref bean="myInterceptor"/>
-                <bean class="org.springframework.web.socket.config.TestChannelInterceptor"/>
             </websocket:interceptors>
         </websocket:client-outbound-channel>
+        <websocket:broker-channel>
+            <websocket:interceptors>
+                <ref bean="myInterceptor"/>
+            </websocket:interceptors>
+        </websocket:broker-channel>
     </websocket:message-broker>
 
-    <bean id="myHandler" class="org.springframework.web.socket.config.TestHandshakeHandler"/>
-
     <bean id="myInterceptor" class="org.springframework.web.socket.config.TestChannelInterceptor"/>
 
 </beans>