Make file and FTP modules as auto-config

* Fix all the Checkstyle violations for those modules

common/spring-file-common/src/main/java/org/springframework/cloud/fn/common/file/FileConsumerProperties.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2020-2020 the original author or authors.
+ * Copyright 2020-2024 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.
@@ -23,6 +23,8 @@
 import org.springframework.validation.annotation.Validated;
 
 /**
+ * The configuration properties for file consumer.
+ *
  * @author David Turanski
  * @author Artem Bilan
  */

common/spring-file-common/src/main/java/org/springframework/cloud/fn/common/file/FileUtils.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2020-2020 the original author or authors.
+ * Copyright 2020-2024 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.
@@ -16,7 +16,7 @@
 
 package org.springframework.cloud.fn.common.file;
 
-import java.util.Collections;
+import java.util.Map;
 
 import org.springframework.integration.dsl.IntegrationFlowBuilder;
 import org.springframework.integration.file.splitter.FileSplitter;
@@ -26,6 +26,8 @@
 import org.springframework.util.MimeTypeUtils;
 
 /**
+ * The utilities for file-based functions.
+ *
  * @author Gary Russell
  * @author Artem Bilan
  * @author Christian Tzolov
@@ -45,29 +47,23 @@ private FileUtils() {
 	 */
 	public static IntegrationFlowBuilder enhanceFlowForReadingMode(IntegrationFlowBuilder flowBuilder,
 			FileConsumerProperties fileConsumerProperties) {
+
 		switch (fileConsumerProperties.getMode()) {
-			case contents:
-				flowBuilder.enrichHeaders(Collections.<String, Object>singletonMap(MessageHeaders.CONTENT_TYPE,
-						MimeTypeUtils.APPLICATION_OCTET_STREAM_VALUE))
-					.transform(new FileToByteArrayTransformer());
-				break;
-			case lines:
+			case contents -> flowBuilder
+				.enrichHeaders(Map.of(MessageHeaders.CONTENT_TYPE, MimeTypeUtils.APPLICATION_OCTET_STREAM_VALUE))
+				.transform(new FileToByteArrayTransformer());
+			case lines -> {
 				Boolean withMarkers = fileConsumerProperties.getWithMarkers();
 				if (withMarkers == null) {
 					withMarkers = false;
 				}
-				flowBuilder
-					.enrichHeaders(Collections.<String, Object>singletonMap(MessageHeaders.CONTENT_TYPE,
-							MimeTypeUtils.TEXT_PLAIN_VALUE))
+				flowBuilder.enrichHeaders(Map.of(MessageHeaders.CONTENT_TYPE, MimeTypeUtils.TEXT_PLAIN_VALUE))
 					.split(new FileSplitter(true, withMarkers, fileConsumerProperties.getMarkersJson()));
-				break;
-			case ref:
-				flowBuilder.enrichHeaders(Collections.<String, Object>singletonMap(MessageHeaders.CONTENT_TYPE,
-						MimeTypeUtils.APPLICATION_JSON_VALUE));
-				break;
-			default:
-				throw new IllegalArgumentException(
-						fileConsumerProperties.getMode().name() + " is not a supported file reading mode.");
+			}
+			case ref ->
+				flowBuilder.enrichHeaders(Map.of(MessageHeaders.CONTENT_TYPE, MimeTypeUtils.APPLICATION_JSON_VALUE));
+			default -> throw new IllegalArgumentException(
+					fileConsumerProperties.getMode().name() + " is not a supported file reading mode.");
 		}
 		return flowBuilder;
 	}
@@ -81,26 +77,21 @@ public static IntegrationFlowBuilder enhanceFlowForReadingMode(IntegrationFlowBu
 	 */
 	public static IntegrationFlowBuilder enhanceStreamFlowForReadingMode(IntegrationFlowBuilder flowBuilder,
 			FileConsumerProperties fileConsumerProperties) {
+
 		switch (fileConsumerProperties.getMode()) {
-			case contents:
-				flowBuilder.enrichHeaders(Collections.<String, Object>singletonMap(MessageHeaders.CONTENT_TYPE,
-						MimeTypeUtils.APPLICATION_OCTET_STREAM_VALUE))
-					.transform(new StreamTransformer());
-				break;
-			case lines:
+			case contents -> flowBuilder
+				.enrichHeaders(Map.of(MessageHeaders.CONTENT_TYPE, MimeTypeUtils.APPLICATION_OCTET_STREAM_VALUE))
+				.transform(new StreamTransformer());
+			case lines -> {
 				Boolean withMarkers = fileConsumerProperties.getWithMarkers();
 				if (withMarkers == null) {
 					withMarkers = false;
 				}
-				flowBuilder
-					.enrichHeaders(Collections.<String, Object>singletonMap(MessageHeaders.CONTENT_TYPE,
-							MimeTypeUtils.TEXT_PLAIN_VALUE))
+				flowBuilder.enrichHeaders(Map.of(MessageHeaders.CONTENT_TYPE, MimeTypeUtils.TEXT_PLAIN_VALUE))
 					.split(new FileSplitter(true, withMarkers, fileConsumerProperties.getMarkersJson()));
-				break;
-			case ref:
-			default:
-				throw new IllegalArgumentException(fileConsumerProperties.getMode().name()
-						+ " is not a supported file reading mode when streaming.");
+			}
+			default -> throw new IllegalArgumentException(
+					fileConsumerProperties.getMode().name() + " is not a supported file reading mode when streaming.");
 		}
 		return flowBuilder;
 	}

common/spring-file-common/src/main/java/org/springframework/cloud/fn/common/file/package-info.java

@@ -0,0 +1,4 @@
+/**
+ * The file-based functions supporting classes.
+ */
+package org.springframework.cloud.fn.common.file;

common/spring-file-common/src/main/java/org/springframework/cloud/fn/common/file/remote/package-info.java

@@ -0,0 +1,4 @@
+/**
+ * The remote file protocols supporting classes.
+ */
+package org.springframework.cloud.fn.common.file.remote;

common/spring-ftp-common/src/main/java/org/springframework/cloud/fn/common/ftp/FtpSessionFactoryConfiguration.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2015-2020 the original author or authors.
+ * Copyright 2015-2024 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.
@@ -18,15 +18,15 @@
 
 import org.apache.commons.net.ftp.FTPFile;
 
+import org.springframework.boot.autoconfigure.AutoConfiguration;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
 import org.springframework.context.annotation.Bean;
-import org.springframework.context.annotation.Configuration;
 import org.springframework.integration.file.remote.session.CachingSessionFactory;
 import org.springframework.integration.file.remote.session.SessionFactory;
 import org.springframework.integration.ftp.session.DefaultFtpSessionFactory;
 
-@Configuration
+@AutoConfiguration
 @EnableConfigurationProperties(FtpSessionFactoryProperties.class)
 public class FtpSessionFactoryConfiguration {
 
@@ -40,8 +40,7 @@ public SessionFactory<FTPFile> ftpSessionFactory(FtpSessionFactoryProperties pro
 		ftpSessionFactory.setPassword(properties.getPassword());
 		ftpSessionFactory.setClientMode(properties.getClientMode().getMode());
 		if (properties.getCacheSessions() != null) {
-			CachingSessionFactory<FTPFile> csf = new CachingSessionFactory<>(ftpSessionFactory);
-			return csf;
+			return new CachingSessionFactory<>(ftpSessionFactory);
 		}
 		else {
 			return ftpSessionFactory;

common/spring-ftp-common/src/main/java/org/springframework/cloud/fn/common/ftp/FtpSessionFactoryProperties.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2015-2020 the original author or authors.
+ * Copyright 2015-2024 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.
@@ -95,7 +95,7 @@ public enum ClientMode {
 		}
 
 		public int getMode() {
-			return mode;
+			return this.mode;
 		}
 
 	}

common/spring-ftp-common/src/main/java/org/springframework/cloud/fn/common/ftp/package-info.java

@@ -0,0 +1,4 @@
+/**
+ * The FTP session factory auto-configuration.
+ */
+package org.springframework.cloud.fn.common.ftp;

common/spring-ftp-common/src/main/resources/META-INF/spring/org.springframework.boot.autoconfigure.AutoConfiguration.imports

@@ -0,0 +1 @@
+org.springframework.cloud.fn.common.ftp.FtpSessionFactoryConfiguration

consumer/spring-file-consumer/src/main/java/org/springframework/cloud/fn/consumer/file/FileConsumerConfiguration.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2015-2022 the original author or authors.
+ * Copyright 2015-2024 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.
@@ -18,29 +18,28 @@
 
 import java.util.function.Consumer;
 
+import org.springframework.boot.autoconfigure.AutoConfiguration;
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
 import org.springframework.cloud.fn.common.config.ComponentCustomizer;
 import org.springframework.context.annotation.Bean;
-import org.springframework.context.annotation.Configuration;
-import org.springframework.expression.ExpressionParser;
-import org.springframework.expression.spel.standard.SpelExpressionParser;
+import org.springframework.expression.Expression;
 import org.springframework.integration.file.DefaultFileNameGenerator;
 import org.springframework.integration.file.FileNameGenerator;
 import org.springframework.integration.file.FileWritingMessageHandler;
 import org.springframework.lang.Nullable;
 import org.springframework.messaging.Message;
 
 /**
+ * The auto-configuration for file consumer.
+ *
  * @author Mark Fisher
  * @author Artem Bilan
  * @author Soby Chacko
  */
-@Configuration(proxyBeanMethods = false)
+@AutoConfiguration
 @EnableConfigurationProperties(FileConsumerProperties.class)
 public class FileConsumerConfiguration {
 
-	private static final ExpressionParser EXPRESSION_PARSER = new SpelExpressionParser();
-
 	private final FileConsumerProperties properties;
 
 	public FileConsumerConfiguration(FileConsumerProperties properties) {
@@ -56,15 +55,15 @@ public Consumer<Message<?>> fileConsumer(FileWritingMessageHandler fileWritingMe
 	public FileWritingMessageHandler fileWritingMessageHandler(FileNameGenerator fileNameGenerator,
 			@Nullable ComponentCustomizer<FileWritingMessageHandler> fileWritingMessageHandlerCustomizer) {
 
-		FileWritingMessageHandler handler = this.properties.getDirectoryExpression() != null
-				? new FileWritingMessageHandler(
-						EXPRESSION_PARSER.parseExpression(this.properties.getDirectoryExpression()))
+		Expression directoryExpression = this.properties.getDirectoryExpression();
+		FileWritingMessageHandler handler = (directoryExpression != null)
+				? new FileWritingMessageHandler(directoryExpression)
 				: new FileWritingMessageHandler(this.properties.getDirectory());
 		handler.setAutoCreateDirectory(true);
-		handler.setAppendNewLine(!properties.isBinary());
-		handler.setCharset(properties.getCharset());
+		handler.setAppendNewLine(!this.properties.isBinary());
+		handler.setCharset(this.properties.getCharset());
 		handler.setExpectReply(false);
-		handler.setFileExistsMode(properties.getMode());
+		handler.setFileExistsMode(this.properties.getMode());
 		handler.setFileNameGenerator(fileNameGenerator);
 
 		if (fileWritingMessageHandlerCustomizer != null) {
@@ -76,7 +75,7 @@ public FileWritingMessageHandler fileWritingMessageHandler(FileNameGenerator fil
 	@Bean
 	public FileNameGenerator fileNameGenerator() {
 		DefaultFileNameGenerator fileNameGenerator = new DefaultFileNameGenerator();
-		fileNameGenerator.setExpression(properties.getNameExpression());
+		fileNameGenerator.setExpression(this.properties.getNameExpression());
 		return fileNameGenerator;
 	}
 

consumer/spring-file-consumer/src/main/java/org/springframework/cloud/fn/consumer/file/FileConsumerProperties.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2015-2020 the original author or authors.
+ * Copyright 2015-2024 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.
@@ -21,12 +21,13 @@
 import jakarta.validation.constraints.AssertTrue;
 
 import org.springframework.boot.context.properties.ConfigurationProperties;
+import org.springframework.expression.Expression;
 import org.springframework.integration.file.support.FileExistsMode;
 import org.springframework.util.StringUtils;
 import org.springframework.validation.annotation.Validated;
 
 /**
- * Properties for the file sink.
+ * Properties for the file consumer.
  *
  * @author Mark Fisher
  * @author Gary Russell
@@ -40,7 +41,8 @@ public class FileConsumerProperties {
 	private static final String DEFAULT_NAME = "file-consumer";
 
 	/**
-	 * A flag to indicate whether adding a newline after the write should be suppressed.
+	 * A flag to indicate whether adding a newline after the write operation should be
+	 * suppressed.
 	 */
 	private boolean binary = false;
 
@@ -57,7 +59,7 @@ public class FileConsumerProperties {
 	/**
 	 * The expression to evaluate for the parent directory of the target file.
 	 */
-	private String directoryExpression;
+	private Expression directoryExpression;
 
 	/**
 	 * The FileExistsMode to use if the target file already exists.
@@ -80,55 +82,56 @@ public class FileConsumerProperties {
 	private String suffix = "";
 
 	public boolean isBinary() {
-		return binary;
+		return this.binary;
 	}
 
 	public void setBinary(boolean binary) {
 		this.binary = binary;
 	}
 
 	public String getCharset() {
-		return charset;
+		return this.charset;
 	}
 
 	public void setCharset(String charset) {
 		this.charset = charset;
 	}
 
 	public File getDirectory() {
-		return directory;
+		return this.directory;
 	}
 
 	public void setDirectory(File directory) {
 		this.directory = directory;
 	}
 
-	public String getDirectoryExpression() {
-		return directoryExpression;
+	public Expression getDirectoryExpression() {
+		return this.directoryExpression;
 	}
 
-	public void setDirectoryExpression(String directoryExpression) {
+	public void setDirectoryExpression(Expression directoryExpression) {
 		this.directoryExpression = directoryExpression;
 	}
 
 	public FileExistsMode getMode() {
-		return mode;
+		return this.mode;
 	}
 
 	public void setMode(FileExistsMode mode) {
 		this.mode = mode;
 	}
 
 	public String getName() {
-		return name;
+		return this.name;
 	}
 
 	public void setName(String name) {
 		this.name = name;
 	}
 
 	public String getNameExpression() {
-		return (nameExpression != null) ? nameExpression + " + '" + getSuffix() + "'" : "'" + name + getSuffix() + "'";
+		return (this.nameExpression != null) ? this.nameExpression + " + '" + getSuffix() + "'"
+				: "'" + this.name + getSuffix() + "'";
 	}
 
 	public void setNameExpression(String nameExpression) {
@@ -137,8 +140,8 @@ public void setNameExpression(String nameExpression) {
 
 	public String getSuffix() {
 		String suffixWithDotIfNecessary = "";
-		if (StringUtils.hasText(suffix)) {
-			suffixWithDotIfNecessary = suffix.startsWith(".") ? suffix : "." + suffix;
+		if (StringUtils.hasText(this.suffix)) {
+			suffixWithDotIfNecessary = this.suffix.startsWith(".") ? this.suffix : "." + this.suffix;
 		}
 		return suffixWithDotIfNecessary;
 	}
@@ -149,12 +152,12 @@ public void setSuffix(String suffix) {
 
 	@AssertTrue(message = "Exactly one of 'name' or 'nameExpression' must be set")
 	public boolean isMutuallyExclusiveNameAndNameExpression() {
-		return DEFAULT_NAME.equals(name) || nameExpression == null;
+		return DEFAULT_NAME.equals(this.name) || this.nameExpression == null;
 	}
 
 	@AssertTrue(message = "Exactly one of 'directory' or 'directoryExpression' must be set")
 	public boolean isMutuallyExclusiveDirectoryAndDirectoryExpression() {
-		return new File(DEFAULT_DIR).equals(directory) || directoryExpression == null;
+		return new File(DEFAULT_DIR).equals(this.directory) || this.directoryExpression == null;
 	}
 
 }

consumer/spring-file-consumer/src/main/java/org/springframework/cloud/fn/consumer/file/package-info.java

@@ -0,0 +1,4 @@
+/**
+ * The file consumer auto-configuration.
+ */
+package org.springframework.cloud.fn.consumer.file;

consumer/spring-file-consumer/src/main/resources/META-INF/spring/org.springframework.boot.autoconfigure.AutoConfiguration.imports

@@ -0,0 +1 @@
+org.springframework.cloud.fn.consumer.file.FileConsumerConfiguration