Fix race condition for FluxMessageChannelTests

The logic in the `FluxMessageChannelTests.testFluxMessageChannelCleanUp()`
relies on the `finishLatch.countDown()` which happens before we
release the lock for a group in the aggregator.
So, when we call a `destroy()` as the next statement, we interrupt
the lock instead of unlocking.
This cause a race condition in the Reactor's `Sink` to terminate properly

* Expose `CorrelationHandlerSpec.releaseLockBeforeSend()` and set it to `true`
in the test to properly unlock before we call `finishLatch.countDown()`
* Deprecate a couple introduced before options in favor of their variants
with `set` prefix
* Fix new Sonar smells

spring-integration-core/src/main/java/org/springframework/integration/dsl/CorrelationHandlerSpec.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2016-2019 the original author or authors.
+ * Copyright 2016-2021 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -336,8 +336,21 @@ public abstract class CorrelationHandlerSpec<S extends CorrelationHandlerSpec<S,
 	 * @return the endpoint spec.
 	 * @since 5.4
 	 * @see AbstractCorrelatingMessageHandler#setExpireTimeout(long)
+	 * @deprecated since 5.5 in favor of {@link #expireTimeout(long)}
 	 */
+	@Deprecated
 	public S setExpireTimeout(long expireTimeout) {
+		return expireTimeout(expireTimeout);
+	}
+
+	/**
+	 * Configure a timeout for old groups in the store to purge.
+	 * @param expireTimeout the timeout in milliseconds to use.
+	 * @return the endpoint spec.
+	 * @since 5.5
+	 * @see AbstractCorrelatingMessageHandler#setExpireTimeout(long)
+	 */
+	public S expireTimeout(long expireTimeout) {
 		this.handler.setExpireTimeout(expireTimeout);
 		return _this();
 	}
@@ -348,10 +361,37 @@ public abstract class CorrelationHandlerSpec<S extends CorrelationHandlerSpec<S,
 	 * @return the endpoint spec.
 	 * @since 5.4
 	 * @see AbstractCorrelatingMessageHandler#setExpireDuration(Duration)
+	 * @deprecated since 5.5 in favor of {@link #expireDuration(Duration)}
 	 */
+	@Deprecated
 	public S setExpireDuration(Duration expireDuration) {
+		return expireDuration(expireDuration);
+	}
+
+	/**
+	 * Configure a {@link Duration} how often to run a scheduled purge task.
+	 * @param expireDuration the duration for scheduled purge task.
+	 * @return the endpoint spec.
+	 * @since 5.5
+	 * @see AbstractCorrelatingMessageHandler#setExpireDuration(Duration)
+	 */
+	public S expireDuration(Duration expireDuration) {
 		this.handler.setExpireDuration(expireDuration);
 		return _this();
 	}
 
+	/**
+	 * Set to true to release the message group lock before sending any output. See
+	 * "Avoiding Deadlocks" in the Aggregator section of the reference manual for more
+	 * information as to why this might be needed.
+	 * @param releaseLockBeforeSend true to release the lock.
+	 * @return the endpoint spec.
+	 * @since 5.5
+	 * @see AbstractCorrelatingMessageHandler#setReleaseLockBeforeSend(boolean)
+	 */
+	public S releaseLockBeforeSend(boolean releaseLockBeforeSend) {
+		this.handler.setReleaseLockBeforeSend(releaseLockBeforeSend);
+		return _this();
+	}
+
 }

spring-integration-core/src/test/java/org/springframework/integration/channel/reactive/FluxMessageChannelTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2016-2020 the original author or authors.
+ * Copyright 2016-2021 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -127,7 +127,7 @@ public class FluxMessageChannelTests {
 		IntegrationFlow testFlow = f -> f
 				.<String>split(__ -> Flux.fromStream(IntStream.range(0, 100).boxed()), null)
 				.channel(flux)
-				.aggregate(a -> a.releaseStrategy(m -> m.size() == 100))
+				.aggregate(a -> a.releaseStrategy(m -> m.size() == 100).releaseLockBeforeSend(true))
 				.handle(__ -> finishLatch.countDown());
 
 		IntegrationFlowContext.IntegrationFlowRegistration flowRegistration =

spring-integration-file/src/main/java/org/springframework/integration/file/filters/CompositeFileListFilter.java

@@ -100,14 +100,11 @@ public class CompositeFileListFilter<F>
 	}
 
 	/**
-	 * Not thread safe. Only a single thread may add filters at a time.
-	 * <p>
 	 * Add the new filters to this CompositeFileListFilter while maintaining the existing filters.
-	 *
 	 * @param filtersToAdd a list of filters to add
 	 * @return this CompositeFileListFilter instance with the added filters
 	 */
-	public CompositeFileListFilter<F> addFilters(Collection<? extends FileListFilter<F>> filtersToAdd) {
+	public synchronized CompositeFileListFilter<F> addFilters(Collection<? extends FileListFilter<F>> filtersToAdd) {
 		for (FileListFilter<F> elf : filtersToAdd) {
 			if (elf instanceof DiscardAwareFileListFilter) {
 				((DiscardAwareFileListFilter<F>) elf).addDiscardCallback(this.discardCallback);
@@ -120,7 +117,7 @@ public class CompositeFileListFilter<F>
 					throw new IllegalStateException(e);
 				}
 			}
-			this.allSupportAccept &= elf.supportsSingleFileFiltering();
+			this.allSupportAccept = this.allSupportAccept && elf.supportsSingleFileFiltering();
 			this.oneIsForRecursion |= elf.isForRecursion();
 		}
 		this.fileFilters.addAll(filtersToAdd);

spring-integration-file/src/main/java/org/springframework/integration/file/remote/gateway/AbstractRemoteFileOutboundGateway.java

@@ -1005,10 +1005,8 @@ public abstract class AbstractRemoteFileOutboundGateway<F> extends AbstractReply
 		if (recursion && StringUtils.hasText(subDirectory)) {
 			fileToAdd = enhanceNameWithSubDirectory(file, subDirectory);
 		}
-		if (this.filterAfterEnhancement) {
-			if (!this.filter.accept(fileToAdd)) {
-				return;
-			}
+		if (this.filterAfterEnhancement && !this.filter.accept(fileToAdd)) {
+			return;
 		}
 		String fileName = getFilename(fileToAdd);
 		final boolean isDirectory = isDirectory(file);
@@ -1020,8 +1018,8 @@ public abstract class AbstractRemoteFileOutboundGateway<F> extends AbstractReply
 		}
 
 		if (recursion && isDirectory && !isDots) {
-			lsFiles.addAll(listFilesInRemoteDir(session, directory, fileName +
-					this.remoteFileTemplate.getRemoteFileSeparator()));
+			lsFiles.addAll(listFilesInRemoteDir(session, directory,
+					fileName + this.remoteFileTemplate.getRemoteFileSeparator()));
 		}
 	}