GH-10083: Apply Nullability to FTP module

spring-integration-ftp/src/main/java/org/springframework/integration/ftp/config/FtpOutboundChannelAdapterParser.java

@@ -16,6 +16,8 @@
 
 package org.springframework.integration.ftp.config;
 
+import java.util.Objects;
+
 import org.w3c.dom.Element;
 
 import org.springframework.beans.factory.config.BeanDefinition;
@@ -55,7 +57,8 @@ protected void postProcessBuilder(BeanDefinitionBuilder builder, Element element
 				.iterator()
 				.next()
 				.getValue();
-		templateDefinition.getPropertyValues() // NOSONAR never null
+
+		Objects.requireNonNull(templateDefinition).getPropertyValues()
 				.add("existsMode", FtpRemoteFileTemplate.ExistsMode.NLST);
 		IntegrationNamespaceUtils.setValueIfAttributeDefined(builder, element, "chmod", "chmodOctal");
 	}

spring-integration-ftp/src/main/java/org/springframework/integration/ftp/config/FtpOutboundGatewayParser.java

@@ -16,6 +16,8 @@
 
 package org.springframework.integration.ftp.config;
 
+import java.util.Objects;
+
 import org.w3c.dom.Element;
 
 import org.springframework.beans.factory.config.BeanDefinition;
@@ -66,7 +68,8 @@ protected void postProcessBuilder(BeanDefinitionBuilder builder, Element element
 				.iterator()
 				.next()
 				.getValue();
-		templateDefinition.getPropertyValues() // NOSONAR never null
+
+		Objects.requireNonNull(templateDefinition).getPropertyValues()
 				.add("existsMode", FtpRemoteFileTemplate.ExistsMode.NLST);
 
 		IntegrationNamespaceUtils.setValueIfAttributeDefined(builder, element, "working-dir-expression",

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

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

spring-integration-ftp/src/main/java/org/springframework/integration/ftp/dsl/Ftp.java

@@ -20,6 +20,7 @@
 import java.util.Comparator;
 
 import org.apache.commons.net.ftp.FTPFile;
+import org.jspecify.annotations.Nullable;
 
 import org.springframework.integration.file.remote.MessageSessionCallback;
 import org.springframework.integration.file.remote.RemoteFileTemplate;
@@ -28,7 +29,6 @@
 import org.springframework.integration.file.support.FileExistsMode;
 import org.springframework.integration.ftp.gateway.FtpOutboundGateway;
 import org.springframework.integration.ftp.session.FtpRemoteFileTemplate;
-import org.springframework.lang.Nullable;
 
 /**
  * The factory for FTP components.
@@ -216,7 +216,7 @@ public static FtpOutboundGatewaySpec outboundGateway(RemoteFileTemplate<FTPFile>
 	 * @see RemoteFileTemplate
 	 */
 	public static FtpOutboundGatewaySpec outboundGateway(RemoteFileTemplate<FTPFile> remoteFileTemplate,
-			AbstractRemoteFileOutboundGateway.Command command, String expression) {
+			AbstractRemoteFileOutboundGateway.Command command, @Nullable String expression) {
 
 		return outboundGateway(remoteFileTemplate, command.getCommand(), expression);
 	}

spring-integration-ftp/src/main/java/org/springframework/integration/ftp/dsl/FtpInboundChannelAdapterSpec.java

@@ -20,6 +20,7 @@
 import java.util.Comparator;
 
 import org.apache.commons.net.ftp.FTPFile;
+import org.jspecify.annotations.Nullable;
 
 import org.springframework.integration.file.dsl.RemoteFileInboundChannelAdapterSpec;
 import org.springframework.integration.file.filters.CompositeFileListFilter;
@@ -31,7 +32,6 @@
 import org.springframework.integration.ftp.inbound.FtpInboundFileSynchronizer;
 import org.springframework.integration.ftp.inbound.FtpInboundFileSynchronizingMessageSource;
 import org.springframework.integration.metadata.SimpleMetadataStore;
-import org.springframework.lang.Nullable;
 
 /**
  * A {@link RemoteFileInboundChannelAdapterSpec} for an {@link FtpInboundFileSynchronizingMessageSource}.

spring-integration-ftp/src/main/java/org/springframework/integration/ftp/dsl/FtpStreamingInboundChannelAdapterSpec.java

@@ -19,6 +19,7 @@
 import java.util.Comparator;
 
 import org.apache.commons.net.ftp.FTPFile;
+import org.jspecify.annotations.Nullable;
 
 import org.springframework.integration.file.dsl.RemoteFileStreamingInboundChannelAdapterSpec;
 import org.springframework.integration.file.filters.CompositeFileListFilter;
@@ -29,7 +30,6 @@
 import org.springframework.integration.ftp.filters.FtpSimplePatternFileListFilter;
 import org.springframework.integration.ftp.inbound.FtpStreamingMessageSource;
 import org.springframework.integration.metadata.SimpleMetadataStore;
-import org.springframework.lang.Nullable;
 
 /**
  * A {@link RemoteFileStreamingInboundChannelAdapterSpec} for a {@link FtpStreamingMessageSource}.

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

@@ -1,6 +1,5 @@
 /**
  * Provides FTP Components for the Java DSL.
  */
-@org.springframework.lang.NonNullApi
-@org.springframework.lang.NonNullFields
+@org.jspecify.annotations.NullMarked
 package org.springframework.integration.ftp.dsl;

spring-integration-ftp/src/main/java/org/springframework/integration/ftp/filters/FtpRegexPatternFileListFilter.java

@@ -41,7 +41,7 @@ public FtpRegexPatternFileListFilter(Pattern pattern) {
 
 	@Override
 	protected String getFilename(FTPFile file) {
-		return (file != null) ? file.getName() : null;
+		return file.getName();
 	}
 
 	@Override

spring-integration-ftp/src/main/java/org/springframework/integration/ftp/filters/FtpSimplePatternFileListFilter.java

@@ -35,7 +35,7 @@ public FtpSimplePatternFileListFilter(String pattern) {
 
 	@Override
 	protected String getFilename(FTPFile file) {
-		return (file != null) ? file.getName() : null;
+		return file.getName();
 	}
 
 	@Override

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

@@ -1,4 +1,5 @@
 /**
  * Provides classes supporting FTP file filtering.
  */
+@org.jspecify.annotations.NullMarked
 package org.springframework.integration.ftp.filters;

spring-integration-ftp/src/main/java/org/springframework/integration/ftp/gateway/FtpOutboundGateway.java

@@ -27,6 +27,7 @@
 
 import org.apache.commons.net.ftp.FTPClient;
 import org.apache.commons.net.ftp.FTPFile;
+import org.jspecify.annotations.Nullable;
 
 import org.springframework.expression.Expression;
 import org.springframework.expression.spel.support.StandardEvaluationContext;
@@ -41,7 +42,6 @@
 import org.springframework.integration.file.remote.session.SessionFactory;
 import org.springframework.integration.ftp.session.FtpFileInfo;
 import org.springframework.integration.ftp.session.FtpRemoteFileTemplate;
-import org.springframework.lang.Nullable;
 import org.springframework.messaging.Message;
 
 /**
@@ -54,8 +54,9 @@
  */
 public class FtpOutboundGateway extends AbstractRemoteFileOutboundGateway<FTPFile> {
 
-	private Expression workingDirExpression;
+	private @Nullable Expression workingDirExpression;
 
+	@SuppressWarnings("NullAway.Init")
 	private StandardEvaluationContext evaluationContext;
 
 	/**
@@ -210,18 +211,18 @@ protected FTPFile enhanceNameWithSubDirectory(FTPFile file, String directory) {
 	}
 
 	@Override
-	protected List<?> ls(Message<?> message, Session<FTPFile> session, String dir) throws IOException {
+	protected List<?> ls(Message<?> message, Session<FTPFile> session, @Nullable String dir) throws IOException {
 		return doInWorkingDirectory(message, session, () -> super.ls(message, session, dir));
 	}
 
 	@Override
-	protected List<String> nlst(Message<?> message, Session<FTPFile> session, String dir) throws IOException {
+	protected List<String> nlst(Message<?> message, Session<FTPFile> session, @Nullable String dir) throws IOException {
 		return doInWorkingDirectory(message, session, () -> super.nlst(message, session, dir));
 	}
 
 	@Override
-	protected File get(Message<?> message, Session<FTPFile> session, String remoteDir, String remoteFilePath,
-			String remoteFilename, FTPFile fileInfoParam) throws IOException {
+	protected File get(Message<?> message, Session<FTPFile> session, @Nullable String remoteDir, String remoteFilePath,
+			String remoteFilename, @Nullable FTPFile fileInfoParam) throws IOException {
 
 		return doInWorkingDirectory(message, session,
 				() -> super.get(message, session, remoteDir, remoteFilePath, remoteFilename, fileInfoParam));
@@ -249,7 +250,7 @@ protected boolean mv(Message<?> message, Session<FTPFile> session, String remote
 	}
 
 	@Override
-	protected String put(Message<?> message, Session<FTPFile> session, String subDirectory) {
+	protected String put(Message<?> message, Session<FTPFile> session, @Nullable String subDirectory) {
 		try {
 			return doInWorkingDirectory(message, session,
 					() -> super.put(message, session, subDirectory));

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

@@ -1,4 +1,5 @@
 /**
  * Provides classes supporting FTP gateways.
  */
+@org.jspecify.annotations.NullMarked
 package org.springframework.integration.ftp.gateway;

spring-integration-ftp/src/main/java/org/springframework/integration/ftp/inbound/FtpInboundFileSynchronizer.java

@@ -42,21 +42,21 @@ public class FtpInboundFileSynchronizer extends AbstractInboundFileSynchronizer<
 	 * {@link org.springframework.integration.file.remote.session.Session} instances.
 	 * @param sessionFactory The session factory.
 	 */
-	@SuppressWarnings("this-escape")
+	@SuppressWarnings({ "this-escape", "NullAway"})// The LiteralExpression can actually handle null ok
 	public FtpInboundFileSynchronizer(SessionFactory<FTPFile> sessionFactory) {
 		super(sessionFactory);
-		doSetRemoteDirectoryExpression(new LiteralExpression(null)); // NOSONAR - LE can actually handle null ok
+		doSetRemoteDirectoryExpression(new LiteralExpression(null));
 		doSetFilter(new FtpPersistentAcceptOnceFileListFilter(new SimpleMetadataStore(), "ftpMessageSource"));
 	}
 
 	@Override
 	protected boolean isFile(FTPFile file) {
-		return file != null && file.isFile();
+		return file.isFile();
 	}
 
 	@Override
 	protected String getFilename(FTPFile file) {
-		return (file != null ? file.getName() : null);
+		return file.getName();
 	}
 
 	@Override

spring-integration-ftp/src/main/java/org/springframework/integration/ftp/inbound/FtpInboundFileSynchronizingMessageSource.java

@@ -20,6 +20,7 @@
 import java.util.Comparator;
 
 import org.apache.commons.net.ftp.FTPFile;
+import org.jspecify.annotations.Nullable;
 
 import org.springframework.integration.file.remote.synchronizer.AbstractInboundFileSynchronizer;
 import org.springframework.integration.file.remote.synchronizer.AbstractInboundFileSynchronizingMessageSource;
@@ -31,6 +32,8 @@
  * @author Josh Long
  * @author Mark Fisher
  * @author Oleg Zhurakousky
+ * @author Artem Bilan
+ *
  * @since 2.0
  */
 public class FtpInboundFileSynchronizingMessageSource extends AbstractInboundFileSynchronizingMessageSource<FTPFile> {
@@ -39,7 +42,9 @@ public FtpInboundFileSynchronizingMessageSource(AbstractInboundFileSynchronizer<
 		super(synchronizer);
 	}
 
-	public FtpInboundFileSynchronizingMessageSource(AbstractInboundFileSynchronizer<FTPFile> synchronizer, Comparator<File> comparator) {
+	public FtpInboundFileSynchronizingMessageSource(AbstractInboundFileSynchronizer<FTPFile> synchronizer,
+			@Nullable Comparator<File> comparator) {
+
 		super(synchronizer, comparator);
 	}
 

spring-integration-ftp/src/main/java/org/springframework/integration/ftp/inbound/FtpStreamingMessageSource.java

@@ -22,6 +22,7 @@
 import java.util.List;
 
 import org.apache.commons.net.ftp.FTPFile;
+import org.jspecify.annotations.Nullable;
 
 import org.springframework.integration.file.remote.AbstractFileInfo;
 import org.springframework.integration.file.remote.AbstractRemoteFileStreamingMessageSource;
@@ -57,7 +58,7 @@ public FtpStreamingMessageSource(RemoteFileTemplate<FTPFile> template) {
 	 * @param comparator the comparator.
 	 */
 	@SuppressWarnings("this-escape")
-	public FtpStreamingMessageSource(RemoteFileTemplate<FTPFile> template, Comparator<FTPFile> comparator) {
+	public FtpStreamingMessageSource(RemoteFileTemplate<FTPFile> template, @Nullable Comparator<FTPFile> comparator) {
 		super(template, comparator);
 		doSetFilter(new FtpPersistentAcceptOnceFileListFilter(new SimpleMetadataStore(), "ftpStreamingMessageSource"));
 	}
@@ -69,7 +70,7 @@ public String getComponentType() {
 
 	@Override
 	protected List<AbstractFileInfo<FTPFile>> asFileInfoList(Collection<FTPFile> files) {
-		List<AbstractFileInfo<FTPFile>> canonicalFiles = new ArrayList<AbstractFileInfo<FTPFile>>();
+		List<AbstractFileInfo<FTPFile>> canonicalFiles = new ArrayList<>();
 		for (FTPFile file : files) {
 			canonicalFiles.add(new FtpFileInfo(file));
 		}
@@ -78,7 +79,7 @@ protected List<AbstractFileInfo<FTPFile>> asFileInfoList(Collection<FTPFile> fil
 
 	@Override
 	protected boolean isDirectory(FTPFile file) {
-		return file != null && file.isDirectory();
+		return file.isDirectory();
 	}
 
 }

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

@@ -1,4 +1,5 @@
 /**
  * Provides classes supporting inbound endpoints.
  */
+@org.jspecify.annotations.NullMarked
 package org.springframework.integration.ftp.inbound;

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

@@ -1,4 +1,5 @@
 /**
  * Provides classes for the FTP outbound channel adapter.
  */
+@org.jspecify.annotations.NullMarked
 package org.springframework.integration.ftp.outbound;

spring-integration-ftp/src/main/java/org/springframework/integration/ftp/server/ApacheMinaFtplet.java

@@ -25,25 +25,26 @@
 import org.apache.ftpserver.ftplet.FtpletResult;
 
 import org.springframework.beans.factory.BeanNameAware;
-import org.springframework.beans.factory.InitializingBean;
 import org.springframework.context.ApplicationEventPublisher;
 import org.springframework.context.ApplicationEventPublisherAware;
-import org.springframework.util.Assert;
 
 /**
  * A listener for FTP events emitted by an Apache Mina ftp server.
  * It emits selected events as Spring Framework {@code ApplicationEvent}s
  * which are subclasses of {@link ApacheMinaFtpEvent}.
  *
  * @author Gary Russell
+ * @author Artem Bilan
+ *
  * @since 5.2
  *
  */
-public class ApacheMinaFtplet extends DefaultFtplet
-		implements ApplicationEventPublisherAware, BeanNameAware, InitializingBean {
+public class ApacheMinaFtplet extends DefaultFtplet implements ApplicationEventPublisherAware, BeanNameAware {
 
+	@SuppressWarnings("NullAway.Init")
 	private ApplicationEventPublisher applicationEventPublisher;
 
+	@SuppressWarnings("NullAway.Init")
 	private String beanName;
 
 	@Override
@@ -64,11 +65,6 @@ public String getBeanName() {
 		return this.beanName;
 	}
 
-	@Override
-	public void afterPropertiesSet() {
-		Assert.state(this.applicationEventPublisher != null, "An ApplicationEventPublisher is required");
-	}
-
 	@Override
 	public FtpletResult onConnect(FtpSession session) throws FtpException, IOException {
 		this.applicationEventPublisher.publishEvent(new SessionOpenedEvent(session));

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

@@ -1,4 +1,5 @@
 /**
  * Provides classes related to FTP servers.
  */
+@org.jspecify.annotations.NullMarked
 package org.springframework.integration.ftp.server;

spring-integration-ftp/src/main/java/org/springframework/integration/ftp/session/AbstractFtpSessionFactory.java

@@ -26,6 +26,7 @@
 import org.apache.commons.net.ftp.FTPClientConfig;
 import org.apache.commons.net.ftp.FTPFile;
 import org.apache.commons.net.ftp.FTPReply;
+import org.jspecify.annotations.Nullable;
 
 import org.springframework.integration.file.remote.session.SessionFactory;
 import org.springframework.messaging.MessagingException;
@@ -46,13 +47,13 @@ public abstract class AbstractFtpSessionFactory<T extends FTPClient> implements
 
 	protected final Log logger = LogFactory.getLog(this.getClass()); // NOSONAR
 
-	private FTPClientConfig config;
+	private @Nullable FTPClientConfig config;
 
-	private String username;
+	private @Nullable String username;
 
-	private String host;
+	private @Nullable String host;
 
-	private String password;
+	private @Nullable String password;
 
 	private int port = FTP.DEFAULT_PORT;
 
@@ -64,11 +65,11 @@ public abstract class AbstractFtpSessionFactory<T extends FTPClient> implements
 
 	private String controlEncoding = FTP.DEFAULT_CONTROL_ENCODING;
 
-	private Integer connectTimeout;
+	private @Nullable Integer connectTimeout;
 
-	private Integer defaultTimeout;
+	private @Nullable Integer defaultTimeout;
 
-	private Integer dataTimeout;
+	private @Nullable Integer dataTimeout;
 
 	/**
 	 * File types defined by {@link org.apache.commons.net.ftp.FTP} constants:
@@ -175,7 +176,7 @@ public FtpSession getSession() {
 	}
 
 	private T createClient() throws IOException {
-		final T client = this.createClientInstance();
+		final T client = createClientInstance();
 		Assert.notNull(client, "client must not be null");
 		client.configure(this.config);
 		Assert.hasText(this.username, "username is required");