GH-10083: Apply Nullability to core routingslip, scattergather, scheduling, and selector packages

spring-integration-core/src/main/java/org/springframework/integration/routingslip/ExpressionEvaluatingRoutingSlipRouteStrategy.java

@@ -16,6 +16,8 @@
 
 package org.springframework.integration.routingslip;
 
+import org.jspecify.annotations.Nullable;
+
 import org.springframework.beans.BeansException;
 import org.springframework.beans.factory.BeanFactory;
 import org.springframework.beans.factory.BeanFactoryAware;
@@ -69,8 +71,10 @@ public class ExpressionEvaluatingRoutingSlipRouteStrategy
 
 	private final Expression expression;
 
+	@SuppressWarnings("NullAway.Init")
 	private EvaluationContext evaluationContext;
 
+	@SuppressWarnings("NullAway.Init")
 	private BeanFactory beanFactory;
 
 	public ExpressionEvaluatingRoutingSlipRouteStrategy(String expression) {
@@ -98,7 +102,7 @@ public void afterPropertiesSet() {
 	}
 
 	@Override
-	public Object getNextPath(Message<?> requestMessage, Object reply) {
+	public @Nullable Object getNextPath(Message<?> requestMessage, Object reply) {
 		return this.expression.getValue(this.evaluationContext, new RequestAndReply(requestMessage, reply));
 	}
 

spring-integration-core/src/main/java/org/springframework/integration/routingslip/RoutingSlipRouteStrategy.java

@@ -16,6 +16,8 @@
 
 package org.springframework.integration.routingslip;
 
+import org.jspecify.annotations.Nullable;
+
 import org.springframework.messaging.Message;
 
 /**
@@ -37,6 +39,7 @@ public interface RoutingSlipRouteStrategy {
 	 * object, a {@link Message} or a {@code AbstractIntegrationMessageBuilder}.
 	 * @return a channel name or another {@link RoutingSlipRouteStrategy}.
 	 */
+	@Nullable
 	Object getNextPath(Message<?> requestMessage, Object reply);
 
 }

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

@@ -1,4 +1,5 @@
 /**
  * Provides classes supporting the RoutingSlip pattern.
  */
+@org.jspecify.annotations.NullMarked
 package org.springframework.integration.routingslip;

spring-integration-core/src/main/java/org/springframework/integration/scattergather/ScatterGatherHandler.java

@@ -16,6 +16,8 @@
 
 package org.springframework.integration.scattergather;
 
+import org.jspecify.annotations.Nullable;
+
 import org.springframework.aop.support.AopUtils;
 import org.springframework.beans.factory.BeanFactory;
 import org.springframework.beans.factory.BeanInitializationException;
@@ -63,13 +65,15 @@ public class ScatterGatherHandler extends AbstractReplyProducingMessageHandler i
 
 	private final MessageHandler gatherer;
 
+	@SuppressWarnings("NullAway.Init")
 	private MessageChannel gatherChannel;
 
 	private String errorChannelName = IntegrationContextUtils.ERROR_CHANNEL_BEAN_NAME;
 
+	@SuppressWarnings("NullAway.Init")
 	private Long gatherTimeout;
 
-	private AbstractEndpoint gatherEndpoint;
+	private @Nullable AbstractEndpoint gatherEndpoint;
 
 	public ScatterGatherHandler(MessageHandler scatterer, MessageHandler gatherer) {
 		this(new FixedSubscriberChannel(scatterer), gatherer);
@@ -185,7 +189,7 @@ private Message<?> enhanceScatterReplyMessage(Message<?> message) {
 	}
 
 	@Override
-	protected Object handleRequestMessage(Message<?> requestMessage) {
+	protected @Nullable Object handleRequestMessage(Message<?> requestMessage) {
 		MessageHeaders requestMessageHeaders = requestMessage.getHeaders();
 		PollableChannel gatherResultChannel = new QueueChannel();
 

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

@@ -1,4 +1,5 @@
 /**
  * Provides classes supporting the Scatter-Gather pattern.
  */
+@org.jspecify.annotations.NullMarked
 package org.springframework.integration.scattergather;

spring-integration-core/src/main/java/org/springframework/integration/scheduling/PollSkipAdvice.java

@@ -20,6 +20,7 @@
 import org.aopalliance.intercept.MethodInvocation;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
+import org.jspecify.annotations.Nullable;
 
 /**
  * An advice that can be added to a poller's advice chain that determines
@@ -47,7 +48,7 @@ public PollSkipAdvice(PollSkipStrategy strategy) {
 	}
 
 	@Override
-	public Object invoke(MethodInvocation invocation) throws Throwable {
+	public @Nullable Object invoke(MethodInvocation invocation) throws Throwable {
 		if ("call".equals(invocation.getMethod().getName()) && this.pollSkipStrategy.skipPoll()) {
 			if (LOGGER.isDebugEnabled()) {
 				LOGGER.debug("Skipping poll because "
@@ -56,9 +57,7 @@ public Object invoke(MethodInvocation invocation) throws Throwable {
 			}
 			return null;
 		}
-		else {
-			return invocation.proceed();
-		}
+		return invocation.proceed();
 	}
 
 	private static final class DefaultPollSkipStrategy implements PollSkipStrategy {

spring-integration-core/src/main/java/org/springframework/integration/scheduling/PollerMetadata.java

@@ -20,6 +20,7 @@
 import java.util.concurrent.Executor;
 
 import org.aopalliance.aop.Advice;
+import org.jspecify.annotations.Nullable;
 
 import org.springframework.beans.factory.BeanFactory;
 import org.springframework.integration.transaction.TransactionSynchronizationFactory;
@@ -56,39 +57,39 @@ public class PollerMetadata {
 	 */
 	public static final String DEFAULT_POLLER = DEFAULT_POLLER_METADATA_BEAN_NAME;
 
-	private Trigger trigger;
+	private @Nullable Trigger trigger;
 
 	private long maxMessagesPerPoll = MAX_MESSAGES_UNBOUNDED;
 
 	private long receiveTimeout = DEFAULT_RECEIVE_TIMEOUT;
 
-	private ErrorHandler errorHandler;
+	private @Nullable ErrorHandler errorHandler;
 
-	private List<Advice> adviceChain;
+	private @Nullable List<Advice> adviceChain;
 
-	private Executor taskExecutor;
+	private @Nullable Executor taskExecutor;
 
-	private TransactionSynchronizationFactory transactionSynchronizationFactory;
+	private @Nullable TransactionSynchronizationFactory transactionSynchronizationFactory;
 
 	public void setTransactionSynchronizationFactory(
 			TransactionSynchronizationFactory transactionSynchronizationFactory) {
 		Assert.notNull(transactionSynchronizationFactory, "'transactionSynchronizationFactory' must not be null");
 		this.transactionSynchronizationFactory = transactionSynchronizationFactory;
 	}
 
-	public TransactionSynchronizationFactory getTransactionSynchronizationFactory() {
+	public @Nullable TransactionSynchronizationFactory getTransactionSynchronizationFactory() {
 		return this.transactionSynchronizationFactory;
 	}
 
-	public void setTrigger(Trigger trigger) {
+	public void setTrigger(@Nullable Trigger trigger) {
 		this.trigger = trigger;
 	}
 
-	public Trigger getTrigger() {
+	public @Nullable Trigger getTrigger() {
 		return this.trigger;
 	}
 
-	public ErrorHandler getErrorHandler() {
+	public @Nullable ErrorHandler getErrorHandler() {
 		return this.errorHandler;
 	}
 
@@ -124,15 +125,15 @@ public void setAdviceChain(List<Advice> adviceChain) {
 		this.adviceChain = adviceChain;
 	}
 
-	public List<Advice> getAdviceChain() {
+	public @Nullable List<Advice> getAdviceChain() {
 		return this.adviceChain;
 	}
 
 	public void setTaskExecutor(Executor taskExecutor) {
 		this.taskExecutor = taskExecutor;
 	}
 
-	public Executor getTaskExecutor() {
+	public @Nullable Executor getTaskExecutor() {
 		return this.taskExecutor;
 	}
 
@@ -141,7 +142,7 @@ public Executor getTaskExecutor() {
 	 * @param beanFactory BeanFactory for lookup, must not be null.
 	 * @return The poller metadata.
 	 */
-	public static PollerMetadata getDefaultPollerMetadata(BeanFactory beanFactory) {
+	public static @Nullable PollerMetadata getDefaultPollerMetadata(BeanFactory beanFactory) {
 		Assert.notNull(beanFactory, "BeanFactory must not be null");
 		if (!beanFactory.containsBean(DEFAULT_POLLER_METADATA_BEAN_NAME)) {
 			return null;

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

@@ -1,4 +1,5 @@
 /**
  * Provides classes related to task scheduling.
  */
+@org.jspecify.annotations.NullMarked
 package org.springframework.integration.scheduling;

spring-integration-core/src/main/java/org/springframework/integration/selector/MetadataStoreSelector.java

@@ -65,24 +65,23 @@ public class MetadataStoreSelector implements MessageSelector {
 
 	private final MessageProcessor<String> keyStrategy;
 
-	private final MessageProcessor<String> valueStrategy;
+	private final @Nullable MessageProcessor<String> valueStrategy;
 
-	@Nullable
-	private BiPredicate<String, String> compareValues;
+	private @Nullable BiPredicate<String, String> compareValues;
 
 	public MetadataStoreSelector(MessageProcessor<String> keyStrategy) {
 		this(keyStrategy, (MessageProcessor<String>) null);
 	}
 
-	public MetadataStoreSelector(MessageProcessor<String> keyStrategy, MessageProcessor<String> valueStrategy) {
+	public MetadataStoreSelector(MessageProcessor<String> keyStrategy, @Nullable MessageProcessor<String> valueStrategy) {
 		this(keyStrategy, valueStrategy, new SimpleMetadataStore());
 	}
 
 	public MetadataStoreSelector(MessageProcessor<String> keyStrategy, ConcurrentMetadataStore metadataStore) {
 		this(keyStrategy, null, metadataStore);
 	}
 
-	public MetadataStoreSelector(MessageProcessor<String> keyStrategy, MessageProcessor<String> valueStrategy,
+	public MetadataStoreSelector(MessageProcessor<String> keyStrategy, @Nullable MessageProcessor<String> valueStrategy,
 			ConcurrentMetadataStore metadataStore) {
 		Assert.notNull(keyStrategy, "'keyStrategy' must not be null");
 		Assert.notNull(metadataStore, "'metadataStore' must not be null");

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

@@ -1,4 +1,5 @@
 /**
  * Provides classes related to message selection.
  */
+@org.jspecify.annotations.NullMarked
 package org.springframework.integration.selector;