Avoid duplicates from <websocket:decorator-factory>

Before this change <websocket:decorator-factory> decorated to
the SubProtocolWebSocketHandler RootBeanDefinition rather than
using a RuntimeBeanReference, which led to a separate instance
of SubProtocolWebSocketHandler to be created.

Issue: SPR-13190

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

@@ -260,7 +260,7 @@ class MessageBrokerBeanDefinitionParser implements BeanDefinitionParser {
 			if (factoriesElement != null) {
 				ManagedList<Object> factories = extractBeanSubElements(factoriesElement, context);
 				RootBeanDefinition factoryBean = new RootBeanDefinition(DecoratingFactoryBean.class);
-				factoryBean.getConstructorArgumentValues().addIndexedArgumentValue(0, handlerDef);
+				factoryBean.getConstructorArgumentValues().addIndexedArgumentValue(0, result);
 				factoryBean.getConstructorArgumentValues().addIndexedArgumentValue(1, factories);
 				result = new RuntimeBeanReference(registerBeanDef(factoryBean, context, source));
 			}

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

@@ -61,6 +61,8 @@ import org.springframework.web.servlet.HandlerMapping;
 import org.springframework.web.servlet.handler.SimpleUrlHandlerMapping;
 import org.springframework.web.socket.WebSocketHandler;
 import org.springframework.web.socket.WebSocketSession;
+import org.springframework.web.socket.handler.ExceptionWebSocketHandlerDecorator;
+import org.springframework.web.socket.handler.LoggingWebSocketHandlerDecorator;
 import org.springframework.web.socket.handler.TestWebSocketSession;
 import org.springframework.web.socket.handler.WebSocketHandlerDecorator;
 import org.springframework.web.socket.handler.WebSocketHandlerDecoratorFactory;
@@ -75,8 +77,15 @@ import org.springframework.web.socket.sockjs.transport.TransportType;
 import org.springframework.web.socket.sockjs.transport.handler.DefaultSockJsService;
 import org.springframework.web.socket.sockjs.transport.handler.WebSocketTransportHandler;
 
-import static org.hamcrest.Matchers.*;
-import static org.junit.Assert.*;
+import static org.hamcrest.Matchers.contains;
+import static org.hamcrest.Matchers.instanceOf;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertSame;
+import static org.junit.Assert.assertThat;
+import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
 
 /**
  * Test fixture for MessageBrokerBeanDefinitionParser.
@@ -123,9 +132,15 @@ public class MessageBrokerBeanDefinitionParserTests {
 		wsHttpRequestHandler.getWebSocketHandler().afterConnectionEstablished(session);
 		assertEquals(true, session.getAttributes().get("decorated"));
 
-		WebSocketHandler wsHandler = unwrapWebSocketHandler(wsHttpRequestHandler.getWebSocketHandler());
-		assertNotNull(wsHandler);
+		WebSocketHandler wsHandler = wsHttpRequestHandler.getWebSocketHandler();
+		assertThat(wsHandler, Matchers.instanceOf(ExceptionWebSocketHandlerDecorator.class));
+		wsHandler = ((ExceptionWebSocketHandlerDecorator) wsHandler).getDelegate();
+		assertThat(wsHandler, Matchers.instanceOf(LoggingWebSocketHandlerDecorator.class));
+		wsHandler = ((LoggingWebSocketHandlerDecorator) wsHandler).getDelegate();
+		assertThat(wsHandler, Matchers.instanceOf(TestWebSocketHandlerDecorator.class));
+		wsHandler = ((TestWebSocketHandlerDecorator) wsHandler).getDelegate();
 		assertThat(wsHandler, Matchers.instanceOf(SubProtocolWebSocketHandler.class));
+		assertSame(wsHandler, this.appContext.getBean(MessageBrokerBeanDefinitionParser.WEB_SOCKET_HANDLER_BEAN_NAME));
 
 		SubProtocolWebSocketHandler subProtocolWsHandler = (SubProtocolWebSocketHandler) wsHandler;
 		assertEquals(Arrays.asList("v10.stomp", "v11.stomp", "v12.stomp"), subProtocolWsHandler.getSubProtocols());
@@ -463,12 +478,19 @@ class TestWebSocketHandlerDecoratorFactory implements WebSocketHandlerDecoratorF
 
 	@Override
 	public WebSocketHandler decorate(WebSocketHandler handler) {
-		return new WebSocketHandlerDecorator(handler) {
-			@Override
-			public void afterConnectionEstablished(WebSocketSession session) throws Exception {
-				session.getAttributes().put("decorated", true);
-				super.afterConnectionEstablished(session);
-			}
-		};
+		return new TestWebSocketHandlerDecorator(handler);
+	}
+}
+
+class TestWebSocketHandlerDecorator extends WebSocketHandlerDecorator {
+
+	public TestWebSocketHandlerDecorator(WebSocketHandler delegate) {
+		super(delegate);
+	}
+
+	@Override
+	public void afterConnectionEstablished(WebSocketSession session) throws Exception {
+		session.getAttributes().put("decorated", true);
+		super.afterConnectionEstablished(session);
 	}
 }