INT-3960: File Outbound - Preserve Timestamp

JIRA: https://jira.spring.io/browse/INT-3960

Polishing - PR Comments

Fix errors according Checkstyle report.
Wrap `warn()` to `isWarnEnable()`.
Polishing for `setPreserveTimestamp()` JavaDocs.

spring-integration-file/src/main/java/org/springframework/integration/file/FileHeaders.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2015 the original author or authors.
+ * Copyright 2002-2016 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.
@@ -39,4 +39,6 @@ public abstract class FileHeaders {
 
 	public static final String RENAME_TO = PREFIX + "renameTo";
 
+	public static final String SET_MODIFIED = PREFIX + "setModified";
+
 }

spring-integration-file/src/main/java/org/springframework/integration/file/FileWritingMessageHandler.java

@@ -152,6 +152,8 @@ public class FileWritingMessageHandler extends AbstractReplyProducingMessageHand
 
 	private volatile MessageFlushPredicate flushPredicate = new DefaultFlushPredicate();
 
+	private volatile boolean preserveTimestamp;
+
 	/**
 	 * Constructor which sets the {@link #destinationDirectoryExpression} using
 	 * a {@link LiteralExpression}.
@@ -327,6 +329,19 @@ public class FileWritingMessageHandler extends AbstractReplyProducingMessageHand
 		this.flushPredicate = flushPredicate;
 	}
 
+	/**
+	 * Set to true to preserve the destination file timestamp. If true and
+	 * the payload is a {@link File}, the payload's {@code lastModified} time will be
+	 * transferred to the destination file. For other payloads, the
+	 * {@link FileHeaders#SET_MODIFIED} header {@value FileHeaders#SET_MODIFIED}
+	 * will be used if present and it's a {@link Number}.
+	 * @param preserveTimestamp the preserveTimestamp to set.
+	 * @since 4.3
+	 */
+	public void setPreserveTimestamp(boolean preserveTimestamp) {
+		this.preserveTimestamp = preserveTimestamp;
+	}
+
 	@Override
 	protected void doInit() {
 		this.evaluationContext = ExpressionUtils.createStandardEvaluationContext(getBeanFactory());
@@ -408,6 +423,7 @@ public class FileWritingMessageHandler extends AbstractReplyProducingMessageHand
 
 		if (!ignore) {
 			try {
+				Object timestamp = requestMessage.getHeaders().get(FileHeaders.SET_MODIFIED);
 				if (!resultFile.exists() &&
 						generatedFileName.replaceAll("/", Matcher.quoteReplacement(File.separator))
 								.contains(File.separator)) {
@@ -415,6 +431,7 @@ public class FileWritingMessageHandler extends AbstractReplyProducingMessageHand
 				}
 				if (payload instanceof File) {
 					resultFile = handleFileMessage((File) payload, tempFile, resultFile);
+					timestamp = ((File) payload).lastModified();
 				}
 				else if (payload instanceof InputStream) {
 					resultFile = handleInputStreamMessage((InputStream) payload, originalFileFromHeader, tempFile,
@@ -432,6 +449,17 @@ public class FileWritingMessageHandler extends AbstractReplyProducingMessageHand
 					throw new IllegalArgumentException(
 							"unsupported Message payload type [" + payload.getClass().getName() + "]");
 				}
+				if (this.preserveTimestamp) {
+					if (timestamp instanceof Number) {
+						resultFile.setLastModified(((Number) timestamp).longValue());
+					}
+					else {
+						if (this.logger.isWarnEnabled()) {
+							this.logger.warn("Could not set lastModified, header " + FileHeaders.SET_MODIFIED
+									+ " must be a Number, not " + timestamp.getClass());
+						}
+					}
+				}
 			}
 			catch (Exception e) {
 				throw new MessageHandlingException(requestMessage, "failed to write Message payload to file", e);

spring-integration-file/src/main/resources/org/springframework/integration/file/config/spring-integration-file-4.3.xsd

@@ -509,6 +509,17 @@ Only files matching this regular expression will be picked up by this adapter.
 				</xsd:appinfo>
 			</xsd:annotation>
 		</xsd:attribute>
+		<xsd:attribute name="preserve-timestamp" type="xsd:string" default="false">
+			<xsd:annotation>
+				<xsd:documentation>
+					Specify whether to preserve the modified timestamp from the source
+					file on the destination file after copying. Applies to 'java.io.File' payloads.
+					For other payload types, the optional 'file_setModified' header will be used,
+					if present (and a 'Number'), to set the lastModified time.
+					By default, the timestamp will NOT be preserved.
+				</xsd:documentation>
+			</xsd:annotation>
+		</xsd:attribute>
 		<xsd:attributeGroup ref="integration:smartLifeCycleAttributeGroup"/>
     </xsd:complexType>
 

spring-integration-file/src/test/java/org/springframework/integration/file/FileWritingMessageHandlerTests.java

@@ -120,13 +120,18 @@ public class FileWritingMessageHandlerTests {
 
 	@Test
 	public void stringPayloadCopiedToNewFile() throws Exception {
-		Message<?> message = MessageBuilder.withPayload(SAMPLE_CONTENT).build();
+		long lastModified = 1234000L;
+		Message<?> message = MessageBuilder.withPayload(SAMPLE_CONTENT)
+				.setHeader(FileHeaders.SET_MODIFIED, lastModified)
+				.build();
 		QueueChannel output = new QueueChannel();
 		handler.setCharset(DEFAULT_ENCODING);
 		handler.setOutputChannel(output);
+		handler.setPreserveTimestamp(true);
 		handler.handleMessage(message);
 		Message<?> result = output.receive(0);
 		assertFileContentIsMatching(result);
+		assertLastModifiedIs(result, lastModified);
 	}
 
 	@Test
@@ -184,11 +189,15 @@ public class FileWritingMessageHandlerTests {
 	@Test
 	public void filePayloadCopiedToNewFile() throws Exception {
 		Message<?> message = MessageBuilder.withPayload(sourceFile).build();
+		long lastModified = 12345000L;
+		sourceFile.setLastModified(lastModified);
 		QueueChannel output = new QueueChannel();
 		handler.setOutputChannel(output);
+		handler.setPreserveTimestamp(true);
 		handler.handleMessage(message);
 		Message<?> result = output.receive(0);
 		assertFileContentIsMatching(result);
+		assertLastModifiedIs(result, lastModified);
 	}
 
 	@Test
@@ -512,10 +521,11 @@ public class FileWritingMessageHandlerTests {
 	}
 
 	void assertFileContentIs(Message<?> result, String expected) throws IOException {
-		assertThat(result, is(notNullValue()));
-		assertThat(result.getPayload(), is(instanceOf(File.class)));
-		File destFile = (File) result.getPayload();
-		assertFileContentIs(destFile, expected);
+		assertFileContentIs(messageToFile(result), expected);
+	}
+
+	void assertLastModifiedIs(Message<?> result, long expected) {
+		assertThat(messageToFile(result).lastModified(), is(expected));
 	}
 
 	void assertFileContentIs(File destFile, String expected) throws IOException {
@@ -525,4 +535,11 @@ public class FileWritingMessageHandlerTests {
 		assertThat(new String(destFileContent, DEFAULT_ENCODING), is(expected));
 	}
 
+	protected File messageToFile(Message<?> result) {
+		assertThat(result, is(notNullValue()));
+		assertThat(result.getPayload(), is(instanceOf(File.class)));
+		File destFile = (File) result.getPayload();
+		return destFile;
+	}
+
 }

src/reference/asciidoc/file.adoc

@@ -105,7 +105,7 @@ to, say, network glitches.
 </bean>
 ----
 
-*The directory scanning and polling*
+*Directory scanning and polling*
 
 The `FileReadingMessageSource` doesn't produce messages for files from the directory immediately.
 It uses an internal queue for 'eligible files' returned by the `scanner`.
@@ -584,6 +584,18 @@ or `FileWritingMessageHandler.MessageFlushPredicate` implementation.
 The predicates are called for each open file.
 See the java docs for these interfaces for more information.
 
+[[file-timestamps]]
+==== File Timestamps
+
+By default, the destination file `lastModified` timestamp will be the time the file was created (except a rename
+in-place will retain the current timestamp).
+Starting with _version 4.3_, you can now configure `preserve-timestamp` (or `setPreserveTimestamp(true)` when using
+Java configuration).
+For `File` payloads, this will transfer the timestamp from the inbound file to the outbound (regardless of whether a
+copy was required).
+For other payloads, if the `FileHeaders.SET_MODIFIED` header (`file_setModified`) is present, it will be used to set
+the destination file's `lastModified` timestamp, as long as the header is a `Number`.
+
 [[file-outbound-channel-adapter]]
 ==== File Outbound Channel Adapter
 

src/reference/asciidoc/whats-new.adoc

@@ -76,6 +76,11 @@ When writing files, you can now specify the buffer size to use.
 You can now avoid flushing files when appending and use a number of strategies to flush the data during idle periods.
 See <<file-flushing>> for more information.
 
+===== Preserving Timestamps
+
+The outbound channel adapter can now be configured to set the destination file's lastmodified timestamp.
+See <<file-timestamps>> for more information.
+
 ==== AMQP Changes
 
 ===== Content Type Message Converter