Address review feedback

* Change `payloadType` to `Class<?>`
* Initialize arrays with empty arrays instead of null

Signed-off-by: Jooyoung Pyoung <[email protected]>

Author: anthologia

spring-integration-websocket/src/main/java/org/springframework/integration/websocket/ServerWebSocketContainer.java

@@ -59,23 +59,21 @@ public class ServerWebSocketContainer extends IntegrationWebSocketContainer
 
 	private final String[] paths;
 
-	@SuppressWarnings("NullAway.Init")
-	private HandshakeHandler handshakeHandler;
+	private @Nullable HandshakeHandler handshakeHandler;
 
-	private HandshakeInterceptor @Nullable [] interceptors;
+	private HandshakeInterceptor[] interceptors = new HandshakeInterceptor[0];
 
 	private WebSocketHandlerDecoratorFactory @Nullable [] decoratorFactories;
 
 	private @Nullable SockJsServiceOptions sockJsServiceOptions;
 
-	private String @Nullable [] origins;
+	private String[] origins = new String[0];
 
 	private boolean autoStartup = true;
 
 	private int phase = 0;
 
-	@SuppressWarnings("NullAway.Init")
-	private TaskScheduler sockJsTaskScheduler;
+	private @Nullable TaskScheduler sockJsTaskScheduler;
 
 	public ServerWebSocketContainer(String... paths) {
 		Assert.notEmpty(paths, "'paths' must not be empty");
@@ -149,7 +147,7 @@ public void setSockJsTaskScheduler(TaskScheduler sockJsTaskScheduler) {
 		this.sockJsTaskScheduler = sockJsTaskScheduler;
 	}
 
-	public TaskScheduler getSockJsTaskScheduler() {
+	public @Nullable TaskScheduler getSockJsTaskScheduler() {
 		return this.sockJsTaskScheduler;
 	}
 
@@ -164,6 +162,7 @@ public void registerWebSocketHandlers(WebSocketHandlerRegistry registry) {
 			}
 		}
 
+		Assert.notNull(this.handshakeHandler, "'handshakeHandler' must not be null");
 		WebSocketHandlerRegistration registration = registry.addHandler(webSocketHandler, this.paths)
 				.setHandshakeHandler(this.handshakeHandler);
 
@@ -240,8 +239,8 @@ public boolean isRunning() {
 	public void start() {
 		this.lock.lock();
 		try {
-			if (this.handshakeHandler instanceof Lifecycle && !isRunning()) {
-				((Lifecycle) this.handshakeHandler).start();
+			if (this.handshakeHandler instanceof Lifecycle lifeCycleHandler && !isRunning()) {
+				lifeCycleHandler.start();
 			}
 		}
 		finally {
@@ -251,15 +250,15 @@ public void start() {
 
 	@Override
 	public void stop() {
-		if (isRunning()) {
-			((Lifecycle) this.handshakeHandler).stop();
+		if (this.handshakeHandler instanceof Lifecycle lifeCycleHandler && isRunning()) {
+			lifeCycleHandler.stop();
 		}
 	}
 
 	@Override
 	public void stop(Runnable callback) {
-		if (isRunning()) {
-			((Lifecycle) this.handshakeHandler).stop();
+		if (this.handshakeHandler instanceof Lifecycle lifeCycleHandler && isRunning()) {
+			lifeCycleHandler.stop();
 		}
 		callback.run();
 	}

spring-integration-websocket/src/main/java/org/springframework/integration/websocket/inbound/WebSocketInboundChannelAdapter.java

@@ -21,7 +21,6 @@
 import java.util.List;
 import java.util.ListIterator;
 import java.util.Map;
-import java.util.concurrent.atomic.AtomicReference;
 
 import org.jspecify.annotations.Nullable;
 
@@ -69,6 +68,7 @@
  *
  * @author Artem Bilan
  * @author Ngoc Nhan
+ * @author Jooyoung Pyoung
  *
  * @since 4.1
  */
@@ -101,7 +101,7 @@ public class WebSocketInboundChannelAdapter extends MessageProducerSupport
 
 	private final MessageChannel subProtocolHandlerChannel;
 
-	private final AtomicReference<Class<?>> payloadType = new AtomicReference<>(String.class);
+	private Class<?> payloadType = String.class;
 
 	@SuppressWarnings("NullAway.Init")
 	private ApplicationEventPublisher eventPublisher;
@@ -166,7 +166,7 @@ public void setMergeWithDefaultConverters(boolean mergeWithDefaultConverters) {
 	 */
 	public void setPayloadType(Class<?> payloadType) {
 		Assert.notNull(payloadType, "'payloadType' must not be null");
-		this.payloadType.set(payloadType);
+		this.payloadType = payloadType;
 	}
 
 	/**
@@ -306,7 +306,7 @@ public boolean isActive() {
 		return active;
 	}
 
-	@SuppressWarnings("unchecked")
+	@SuppressWarnings({"unchecked", "NullAway"}) // Dataflow analysis limitation
 	private void handleMessageAndSend(final Message<?> message) {
 		SimpMessageHeaderAccessor headerAccessor = SimpMessageHeaderAccessor.wrap(message);
 		StompCommand stompCommand = (StompCommand) headerAccessor.getHeader("stompCommand");
@@ -327,7 +327,6 @@ else if (StompCommand.RECEIPT.equals(stompCommand)) {
 		}
 		else {
 			if (this.useBroker) {
-				Assert.notNull(this.brokerHandler, "brokerHandler is required");
 				this.brokerHandler.handleMessage(message);
 			}
 			else {
@@ -350,9 +349,9 @@ private boolean isProcessingTypeOrCommand(SimpMessageHeaderAccessor headerAccess
 				&& !checkDestinationPrefix(headerAccessor.getDestination());
 	}
 
+	@SuppressWarnings("NullAway") // Dataflow analysis limitation
 	private boolean checkDestinationPrefix(@Nullable String destination) {
 		if (this.useBroker) {
-			Assert.notNull(this.brokerHandler, "brokerHandler is required");
 			Collection<String> destinationPrefixes = this.brokerHandler.getDestinationPrefixes();
 			if ((destination == null) || CollectionUtils.isEmpty(destinationPrefixes)) {
 				return false;
@@ -379,14 +378,11 @@ private void produceConnectAckMessage(Message<?> message, SimpMessageHeaderAcces
 	}
 
 	private void produceMessage(Message<?> message, SimpMessageHeaderAccessor headerAccessor) {
-		Class<?> targetType = this.payloadType.get();
-		Assert.notNull(targetType, "payloadType must not be null");
-
-		Object payload = this.messageConverter.fromMessage(message, targetType);
+		Object payload = this.messageConverter.fromMessage(message, this.payloadType);
 		Assert.state(payload != null,
 				() -> "The message converter '" + this.messageConverter +
 						"' produced no payload for message '" + message +
-						"' and expected payload type: " + this.payloadType.get());
+						"' and expected payload type: " + this.payloadType);
 		Message<Object> messageToSend =
 				getMessageBuilderFactory()
 						.withPayload(payload)

spring-integration-websocket/src/test/java/org/springframework/integration/websocket/config/WebSocketParserTests.java

@@ -21,7 +21,6 @@
 import java.util.Arrays;
 import java.util.List;
 import java.util.Map;
-import java.util.concurrent.atomic.AtomicReference;
 
 import org.junit.jupiter.api.Test;
 
@@ -62,6 +61,7 @@
 /**
  * @author Artem Bilan
  * @author Julian Koch
+ * @author Jooyoung Pyoung
  *
  * @since 4.1
  */
@@ -193,7 +193,7 @@ public void testDefaultInboundChannelAdapterAndServerContainer() {
 		assertThat(TestUtils.getPropertyValue(this.defaultInboundAdapter, "messageConverters")).isNull();
 		assertThat(TestUtils.getPropertyValue(this.defaultInboundAdapter, "defaultConverters"))
 				.isEqualTo(TestUtils.getPropertyValue(this.defaultInboundAdapter, "messageConverter.converters"));
-		assertThat(TestUtils.getPropertyValue(this.defaultInboundAdapter, "payloadType", AtomicReference.class).get())
+		assertThat(TestUtils.getPropertyValue(this.defaultInboundAdapter, "payloadType", Class.class))
 				.isEqualTo(String.class);
 		assertThat(TestUtils.getPropertyValue(this.defaultInboundAdapter, "useBroker", Boolean.class)).isTrue();
 		assertThat(TestUtils.getPropertyValue(this.defaultInboundAdapter, "brokerHandler"))
@@ -218,7 +218,7 @@ public void testCustomInboundChannelAdapterAndClientContainer() throws URISyntax
 				.isEqualTo(2000L);
 		assertThat(TestUtils.getPropertyValue(this.customInboundAdapter, "phase")).isEqualTo(200);
 		assertThat(TestUtils.getPropertyValue(this.customInboundAdapter, "autoStartup", Boolean.class)).isFalse();
-		assertThat(TestUtils.getPropertyValue(this.customInboundAdapter, "payloadType", AtomicReference.class).get())
+		assertThat(TestUtils.getPropertyValue(this.customInboundAdapter, "payloadType", Class.class))
 				.isEqualTo(Integer.class);
 		SubProtocolHandlerRegistry subProtocolHandlerRegistry = TestUtils.getPropertyValue(this.customInboundAdapter,
 				"subProtocolHandlerRegistry", SubProtocolHandlerRegistry.class);