GH-10083: Apply Nullability to TCP/IP module

spring-integration-core/src/main/java/org/springframework/integration/context/IntegrationObjectSupport.java

@@ -211,8 +211,7 @@ public void setChannelResolver(DestinationResolver<MessageChannel> channelResolv
 	}
 
 	@Override
-	@Nullable
-	public Expression getExpression() {
+	public @Nullable Expression getExpression() {
 		return this.expression;
 	}
 

spring-integration-ip/src/main/java/org/springframework/integration/ip/AbstractInternetProtocolReceivingChannelAdapter.java

@@ -20,6 +20,8 @@
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 
+import org.jspecify.annotations.Nullable;
+
 import org.springframework.context.ApplicationEventPublisher;
 import org.springframework.context.ApplicationEventPublisherAware;
 import org.springframework.integration.endpoint.MessageProducerSupport;
@@ -41,6 +43,7 @@ public abstract class AbstractInternetProtocolReceivingChannelAdapter
 
 	private final int port;
 
+	@SuppressWarnings("NullAway.Init")
 	private ApplicationEventPublisher applicationEventPublisher;
 
 	private int soTimeout = 0;
@@ -49,9 +52,9 @@ public abstract class AbstractInternetProtocolReceivingChannelAdapter
 
 	private int receiveBufferSize = 2048; // NOSONAR magic number
 
-	private String localAddress;
+	private @Nullable String localAddress;
 
-	private Executor taskExecutor;
+	private @Nullable Executor taskExecutor;
 
 	private boolean taskExecutorSet;
 
@@ -117,7 +120,7 @@ public void setListening(boolean listening) {
 		this.listening = listening;
 	}
 
-	public String getLocalAddress() {
+	public @Nullable String getLocalAddress() {
 		return this.localAddress;
 	}
 
@@ -139,7 +142,7 @@ public void setTaskExecutor(Executor taskExecutor) {
 	/**
 	 * @return the taskExecutor
 	 */
-	public Executor getTaskExecutor() {
+	public @Nullable Executor getTaskExecutor() {
 		return this.taskExecutor;
 	}
 
@@ -153,6 +156,7 @@ public void setApplicationEventPublisher(ApplicationEventPublisher applicationEv
 	}
 
 	@Override
+	@SuppressWarnings("NullAway") // Dataflow analysis limitation
 	protected void doStart() {
 		String beanName = getComponentName();
 		checkTaskExecutor((beanName == null ? "" : beanName + "-") + getComponentType());
@@ -179,8 +183,9 @@ protected void checkTaskExecutor(final String threadName) {
 
 	@Override
 	protected void doStop() {
-		if (!this.taskExecutorSet && this.taskExecutor != null) {
-			((ExecutorService) this.taskExecutor).shutdown();
+		Executor taskExecutorToShutdown = this.taskExecutor;
+		if (!this.taskExecutorSet && taskExecutorToShutdown != null) {
+			((ExecutorService) taskExecutorToShutdown).shutdown();
 			this.taskExecutor = null;
 		}
 	}

spring-integration-ip/src/main/java/org/springframework/integration/ip/config/TcpConnectionFactoryFactoryBean.java

@@ -18,6 +18,8 @@
 
 import java.util.concurrent.Executor;
 
+import org.jspecify.annotations.Nullable;
+
 import org.springframework.beans.BeansException;
 import org.springframework.beans.factory.BeanFactory;
 import org.springframework.beans.factory.BeanNameAware;
@@ -62,11 +64,12 @@
 public class TcpConnectionFactoryFactoryBean extends AbstractFactoryBean<AbstractConnectionFactory>
 		implements Lifecycle, BeanNameAware, ApplicationEventPublisherAware, ApplicationContextAware {
 
+	@SuppressWarnings("NullAway.Init")
 	private AbstractConnectionFactory connectionFactory;
 
-	private String type;
+	private @Nullable String type;
 
-	private String host;
+	private @Nullable String host;
 
 	private int port;
 
@@ -84,7 +87,7 @@ public class TcpConnectionFactoryFactoryBean extends AbstractFactoryBean<Abstrac
 
 	private int soTrafficClass = -1; // don't set by default
 
-	private Executor taskExecutor;
+	private @Nullable Executor taskExecutor;
 
 	private Deserializer<?> deserializer = new ByteArrayCrLfSerializer();
 
@@ -98,38 +101,41 @@ public class TcpConnectionFactoryFactoryBean extends AbstractFactoryBean<Abstrac
 
 	private int backlog = 5; // NOSONAR magic number
 
-	private TcpConnectionInterceptorFactoryChain interceptorFactoryChain;
+	private @Nullable TcpConnectionInterceptorFactoryChain interceptorFactoryChain;
 
 	private boolean lookupHost = true;
 
-	private String localAddress;
+	private @Nullable String localAddress;
 
 	private boolean usingNio;
 
 	private boolean usingDirectBuffers;
 
+	@SuppressWarnings("NullAway.Init")
 	private String beanName;
 
 	private boolean applySequence;
 
-	private Long readDelay;
+	private @Nullable Long readDelay;
 
-	private TcpSSLContextSupport sslContextSupport;
+	private @Nullable TcpSSLContextSupport sslContextSupport;
 
-	private Integer sslHandshakeTimeout;
+	private @Nullable Integer sslHandshakeTimeout;
 
 	private TcpSocketSupport socketSupport = new DefaultTcpSocketSupport();
 
-	private TcpNioConnectionSupport nioConnectionSupport;
+	private @Nullable TcpNioConnectionSupport nioConnectionSupport;
 
-	private TcpNetConnectionSupport netConnectionSupport;
+	private @Nullable TcpNetConnectionSupport netConnectionSupport;
 
-	private TcpSocketFactorySupport socketFactorySupport;
+	private @Nullable TcpSocketFactorySupport socketFactorySupport;
 
+	@SuppressWarnings("NullAway.Init")
 	private ApplicationEventPublisher applicationEventPublisher;
 
-	private Integer connectTimeout;
+	private @Nullable Integer connectTimeout;
 
+	@SuppressWarnings("NullAway.Init")
 	private ApplicationContext applicationContext;
 
 	public TcpConnectionFactoryFactoryBean() {
@@ -169,6 +175,7 @@ protected AbstractConnectionFactory createInstance() {
 				this.connectionFactory = factory;
 			}
 			else {
+				Assert.notNull(this.host, "The 'host' must be provided for client factory.");
 				TcpNioClientConnectionFactory factory = new TcpNioClientConnectionFactory(this.host, this.port);
 				this.setCommonAttributes(factory);
 				factory.setUsingDirectBuffers(this.usingDirectBuffers);
@@ -189,8 +196,8 @@ protected AbstractConnectionFactory createInstance() {
 				this.connectionFactory = factory;
 			}
 			else {
-				TcpNetClientConnectionFactory factory = new TcpNetClientConnectionFactory(
-						this.host, this.port);
+				Assert.notNull(this.host, "The 'host' must be provided for client factory.");
+				TcpNetClientConnectionFactory factory = new TcpNetClientConnectionFactory(this.host, this.port);
 				this.setCommonAttributes(factory);
 				factory.setTcpSocketFactorySupport(this.obtainSocketFactorySupport());
 				factory.setTcpNetConnectionSupport(this.obtainNetConnectionSupport());
@@ -203,16 +210,16 @@ protected AbstractConnectionFactory createInstance() {
 		if (beanFactory != null) {
 			this.connectionFactory.setBeanFactory(beanFactory);
 		}
-		if (this.applicationContext != null) {
-			this.connectionFactory.setApplicationContext(this.applicationContext);
-		}
+		this.connectionFactory.setApplicationContext(this.applicationContext);
 		this.connectionFactory.afterPropertiesSet();
 		return this.connectionFactory;
 	}
 
 	private void setCommonAttributes(AbstractConnectionFactory factory) {
 		factory.setDeserializer(this.deserializer);
-		factory.setInterceptorFactoryChain(this.interceptorFactoryChain);
+		if (this.interceptorFactoryChain != null) {
+			factory.setInterceptorFactoryChain(this.interceptorFactoryChain);
+		}
 		factory.setLookupHost(this.lookupHost);
 		this.mapper.setApplySequence(this.applySequence);
 		factory.setMapper(this.mapper);
@@ -225,7 +232,9 @@ private void setCommonAttributes(AbstractConnectionFactory factory) {
 		factory.setSoTcpNoDelay(this.soTcpNoDelay);
 		factory.setSoTimeout(this.soTimeout);
 		factory.setSoTrafficClass(this.soTrafficClass);
-		factory.setTaskExecutor(this.taskExecutor);
+		if (this.taskExecutor != null) {
+			factory.setTaskExecutor(this.taskExecutor);
+		}
 		factory.setBeanName(this.beanName);
 		factory.setTcpSocketSupport(this.socketSupport);
 		factory.setApplicationEventPublisher(this.applicationEventPublisher);
@@ -235,7 +244,9 @@ private void setCommonAttributes(AbstractConnectionFactory factory) {
 	}
 
 	private void setServerAttributes(AbstractServerConnectionFactory factory) {
-		factory.setLocalAddress(this.localAddress);
+		if (this.localAddress != null) {
+			factory.setLocalAddress(this.localAddress);
+		}
 		factory.setBacklog(this.backlog);
 	}
 
@@ -264,12 +275,7 @@ private TcpNioConnectionSupport obtainNioConnectionSupport() {
 	}
 
 	private TcpNetConnectionSupport obtainNetConnectionSupport() {
-		if (this.netConnectionSupport != null) {
-			return this.netConnectionSupport;
-		}
-		else {
-			return new DefaultTcpNetConnectionSupport();
-		}
+		return this.netConnectionSupport != null ? this.netConnectionSupport : new DefaultTcpNetConnectionSupport();
 	}
 
 	/**

spring-integration-ip/src/main/java/org/springframework/integration/ip/config/package-info.java

@@ -1,4 +1,5 @@
 /**
  * Provides classes for configuration - parsers, namespace handlers, factory beans.
  */
+@org.jspecify.annotations.NullMarked
 package org.springframework.integration.ip.config;

spring-integration-ip/src/main/java/org/springframework/integration/ip/dsl/TcpInboundChannelAdapterSpec.java

@@ -19,6 +19,8 @@
 import java.util.Collections;
 import java.util.Map;
 
+import org.jspecify.annotations.Nullable;
+
 import org.springframework.integration.dsl.ComponentsRegistration;
 import org.springframework.integration.dsl.MessageProducerSpec;
 import org.springframework.integration.ip.tcp.TcpReceivingChannelAdapter;
@@ -38,7 +40,7 @@ public class TcpInboundChannelAdapterSpec
 		extends MessageProducerSpec<TcpInboundChannelAdapterSpec, TcpReceivingChannelAdapter>
 		implements ComponentsRegistration {
 
-	protected final AbstractConnectionFactory connectionFactory; // NOSONAR - final
+	protected final @Nullable AbstractConnectionFactory connectionFactory; // NOSONAR - final
 
 	/**
 	 * Construct an instance using an existing spring-managed connection factory.
@@ -91,10 +93,10 @@ public TcpInboundChannelAdapterSpec taskScheduler(TaskScheduler taskScheduler) {
 	}
 
 	@Override
-	public Map<Object, String> getComponentsToRegister() {
+	public Map<Object, @Nullable String> getComponentsToRegister() {
 		return this.connectionFactory != null
-				? Collections.singletonMap(this.connectionFactory, this.connectionFactory.getComponentName())
-				: Collections.emptyMap();
+				? Collections.<Object, @Nullable String>singletonMap(this.connectionFactory, this.connectionFactory.getComponentName())
+				: Collections.<Object, @Nullable String>emptyMap();
 	}
 
 }

spring-integration-ip/src/main/java/org/springframework/integration/ip/dsl/TcpInboundGatewaySpec.java

@@ -19,6 +19,8 @@
 import java.util.Collections;
 import java.util.Map;
 
+import org.jspecify.annotations.Nullable;
+
 import org.springframework.integration.dsl.ComponentsRegistration;
 import org.springframework.integration.dsl.MessagingGatewaySpec;
 import org.springframework.integration.ip.tcp.TcpInboundGateway;
@@ -37,7 +39,7 @@
 public class TcpInboundGatewaySpec extends MessagingGatewaySpec<TcpInboundGatewaySpec, TcpInboundGateway>
 		implements ComponentsRegistration {
 
-	protected final AbstractConnectionFactory connectionFactory; // NOSONAR - final
+	protected final @Nullable AbstractConnectionFactory connectionFactory; // NOSONAR - final
 
 	/**
 	 * Construct an instance using an existing spring-managed connection factory.
@@ -90,10 +92,10 @@ public TcpInboundGatewaySpec taskScheduler(TaskScheduler taskScheduler) {
 	}
 
 	@Override
-	public Map<Object, String> getComponentsToRegister() {
+	public Map<Object, @Nullable String> getComponentsToRegister() {
 		return this.connectionFactory != null
-				? Collections.singletonMap(this.connectionFactory, this.connectionFactory.getComponentName())
-				: Collections.emptyMap();
+				? Collections.<Object, @Nullable String>singletonMap(this.connectionFactory, this.connectionFactory.getComponentName())
+				: Collections.<Object, @Nullable String>emptyMap();
 	}
 
 }

spring-integration-ip/src/main/java/org/springframework/integration/ip/dsl/TcpOutboundChannelAdapterSpec.java

@@ -19,6 +19,8 @@
 import java.util.Collections;
 import java.util.Map;
 
+import org.jspecify.annotations.Nullable;
+
 import org.springframework.integration.dsl.ComponentsRegistration;
 import org.springframework.integration.dsl.MessageHandlerSpec;
 import org.springframework.integration.ip.tcp.TcpSendingMessageHandler;
@@ -38,7 +40,7 @@ public class TcpOutboundChannelAdapterSpec
 		extends MessageHandlerSpec<TcpOutboundChannelAdapterSpec, TcpSendingMessageHandler>
 		implements ComponentsRegistration {
 
-	protected final AbstractConnectionFactory connectionFactory; // NOSONAR - final
+	protected final @Nullable AbstractConnectionFactory connectionFactory; // NOSONAR - final
 
 	/**
 	 * Construct an instance using an existing spring-managed connection factory.
@@ -91,10 +93,10 @@ public TcpOutboundChannelAdapterSpec taskScheduler(TaskScheduler taskScheduler)
 	}
 
 	@Override
-	public Map<Object, String> getComponentsToRegister() {
+	public Map<Object, @Nullable String> getComponentsToRegister() {
 		return this.connectionFactory != null
-				? Collections.singletonMap(this.connectionFactory, this.connectionFactory.getComponentName())
-				: Collections.emptyMap();
+				? Collections.<Object, @Nullable String>singletonMap(this.connectionFactory, this.connectionFactory.getComponentName())
+				: Collections.<Object, @Nullable String>emptyMap();
 	}
 
 }

spring-integration-ip/src/main/java/org/springframework/integration/ip/dsl/TcpOutboundGatewaySpec.java

@@ -20,6 +20,8 @@
 import java.util.Map;
 import java.util.function.Function;
 
+import org.jspecify.annotations.Nullable;
+
 import org.springframework.integration.dsl.ComponentsRegistration;
 import org.springframework.integration.dsl.MessageHandlerSpec;
 import org.springframework.integration.expression.FunctionExpression;
@@ -40,7 +42,7 @@
 public class TcpOutboundGatewaySpec extends MessageHandlerSpec<TcpOutboundGatewaySpec, TcpOutboundGateway>
 		implements ComponentsRegistration {
 
-	protected final AbstractClientConnectionFactory connectionFactory; // NOSONAR - final
+	protected final @Nullable AbstractClientConnectionFactory connectionFactory; // NOSONAR - final
 
 	/**
 	 * Construct an instance using an existing spring-managed connection factory.
@@ -138,10 +140,10 @@ public TcpOutboundGatewaySpec unsolicitedMessageChannel(MessageChannel channel)
 	}
 
 	@Override
-	public Map<Object, String> getComponentsToRegister() {
+	public Map<Object, @Nullable String> getComponentsToRegister() {
 		return this.connectionFactory != null
-				? Collections.singletonMap(this.connectionFactory, this.connectionFactory.getComponentName())
-				: Collections.emptyMap();
+				? Collections.<Object, @Nullable String>singletonMap(this.connectionFactory, this.connectionFactory.getComponentName())
+				: Collections.<Object, @Nullable String>emptyMap();
 	}
 
 }

spring-integration-ip/src/main/java/org/springframework/integration/ip/dsl/package-info.java

@@ -1,5 +1,5 @@
 /**
  * Provides TCP/UDP Component support for the Java DSL.
  */
-@org.springframework.lang.NonNullApi
+@org.jspecify.annotations.NullMarked
 package org.springframework.integration.ip.dsl;

spring-integration-ip/src/main/java/org/springframework/integration/ip/event/package-info.java

@@ -1,4 +1,5 @@
 /**
  * ApplicationEvents generated by the ip module.
  */
+@org.jspecify.annotations.NullMarked
 package org.springframework.integration.ip.event;

spring-integration-ip/src/main/java/org/springframework/integration/ip/package-info.java

@@ -1,4 +1,5 @@
 /**
  * Base package for IP (TCP/UDP) Support.
  */
+@org.jspecify.annotations.NullMarked
 package org.springframework.integration.ip;