GH-9869: Introduce AbstractRecentFileListFilter strategy

Fixes: #9869

Currently, FileListFilters on the last modified attribute of a file are limited to the use case of discarding files that are too young.
It would be great to have a filter implementation which would accept files which are not old enough.

* Implement `AbstractRecentFileListFilter` for all the supported file protocols

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

@@ -0,0 +1,81 @@
+/*
+ * Copyright 2025 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.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.integration.file.filters;
+
+import java.time.Duration;
+import java.time.Instant;
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * The {@link FileListFilter} to accept only files which are recent according to provided {@code age}:
+ * the {@code lastModified} of the file is more than the age in comparison with the current time.
+ * In other words, accept those files which are not old enough yet.
+ *
+ * @param <F> The type that will be filtered.
+ *
+ * @author Artem Bilan
+ *
+ * @since 6.5
+ */
+public abstract class AbstractRecentFileListFilter<F> implements FileListFilter<F> {
+
+	protected static final long ONE_SECOND = 1000;
+
+	private final Duration age;
+
+	/**
+	 * Construct an instance with default age as 1 day.
+	 */
+	public AbstractRecentFileListFilter() {
+		this(Duration.ofDays(1));
+	}
+
+	public AbstractRecentFileListFilter(Duration age) {
+		this.age = age;
+	}
+
+	@Override
+	public boolean supportsSingleFileFiltering() {
+		return true;
+	}
+
+	@Override
+	public List<F> filterFiles(F[] files) {
+		List<F> list = new ArrayList<>();
+		Instant now = Instant.now();
+		for (F file : files) {
+			if (!fileIsAged(file, now)) {
+				list.add(file);
+			}
+		}
+
+		return list;
+	}
+
+	@Override
+	public boolean accept(F file) {
+		return !fileIsAged(file, Instant.now());
+	}
+
+	protected boolean fileIsAged(F file, Instant now) {
+		return getLastModified(file).plus(this.age).isBefore(now);
+	}
+
+	protected abstract Instant getLastModified(F remoteFile);
+
+}

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

@@ -0,0 +1,44 @@
+/*
+ * Copyright 2025 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.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.integration.file.filters;
+
+import java.io.File;
+import java.time.Duration;
+import java.time.Instant;
+
+/**
+ * The {@link AbstractRecentFileListFilter} implementation for local file system.
+ *
+ * @author Artem Bilan
+ *
+ * @since 6.5
+ */
+public class RecentFileListFilter extends AbstractRecentFileListFilter<File> {
+
+	public RecentFileListFilter() {
+	}
+
+	public RecentFileListFilter(Duration age) {
+		super(age);
+	}
+
+	@Override
+	protected Instant getLastModified(File file) {
+		return Instant.ofEpochSecond(file.lastModified() / ONE_SECOND);
+	}
+
+}

spring-integration-file/src/test/java/org/springframework/integration/file/filters/RecentFileListFilterTests.java

@@ -0,0 +1,56 @@
+/*
+ * Copyright 2025 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.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.integration.file.filters;
+
+import java.io.File;
+import java.io.FileOutputStream;
+import java.time.Duration;
+import java.time.Instant;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * @author Artem Bilan
+ *
+ * @since 6.5
+ *
+ */
+public class RecentFileListFilterTests {
+
+	@TempDir
+	public File folder;
+
+	@Test
+	public void testAge() throws Exception {
+		RecentFileListFilter filter = new RecentFileListFilter(Duration.ofHours(20));
+		File testFile = new File(folder, "test.tmp");
+		FileOutputStream fileOutputStream = new FileOutputStream(testFile);
+		fileOutputStream.write("x".getBytes());
+		fileOutputStream.close();
+		assertThat(filter.filterFiles(new File[] {testFile})).hasSize(1);
+		assertThat(filter.accept(testFile)).isTrue();
+
+		testFile.setLastModified(Instant.now().minus(Duration.ofDays(1)).toEpochMilli());
+
+		assertThat(filter.filterFiles(new File[] {testFile})).hasSize(0);
+		assertThat(filter.accept(testFile)).isFalse();
+	}
+
+}

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

@@ -0,0 +1,48 @@
+/*
+ * Copyright 2025 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.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.integration.ftp.filters;
+
+import java.time.Duration;
+import java.time.Instant;
+
+import org.apache.commons.net.ftp.FTPFile;
+
+import org.springframework.integration.file.filters.AbstractRecentFileListFilter;
+
+/**
+ * The {@link AbstractRecentFileListFilter} implementation for FTP protocol.
+ *
+ * @author Artem Bilan
+ *
+ * @since 6.5
+ */
+public class FtpRecentFileListFilter extends AbstractRecentFileListFilter<FTPFile> {
+
+	public FtpRecentFileListFilter() {
+		super();
+	}
+
+	public FtpRecentFileListFilter(Duration age) {
+		super(age);
+	}
+
+	@Override
+	protected Instant getLastModified(FTPFile remoteFile) {
+		return remoteFile.getTimestampInstant();
+	}
+
+}

spring-integration-ftp/src/test/java/org/springframework/integration/ftp/filters/FtpRecentFileListFilterTests.java

@@ -0,0 +1,57 @@
+/*
+ * Copyright 2025 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.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.integration.ftp.filters;
+
+import java.time.Duration;
+import java.util.Calendar;
+
+import org.apache.commons.net.ftp.FTPFile;
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * @author Artem Bilan
+ *
+ * @since 6.5
+ */
+public class FtpRecentFileListFilterTests {
+
+	@Test
+	public void testAge() {
+		FtpRecentFileListFilter filter = new FtpRecentFileListFilter(Duration.ofHours(20));
+		FTPFile ftpFile1 = new FTPFile();
+		ftpFile1.setName("foo");
+		ftpFile1.setTimestamp(Calendar.getInstance());
+		FTPFile ftpFile2 = new FTPFile();
+		ftpFile2.setName("bar");
+		ftpFile2.setTimestamp(Calendar.getInstance());
+		FTPFile[] files = new FTPFile[] {ftpFile1, ftpFile2};
+		assertThat(filter.filterFiles(files)).hasSize(2);
+		assertThat(filter.accept(ftpFile1)).isTrue();
+		assertThat(filter.accept(ftpFile2)).isTrue();
+
+		// Make a file as of yesterday's
+		final Calendar calendar = Calendar.getInstance();
+		calendar.add(Calendar.DATE, -1);
+		ftpFile2.setTimestamp(calendar);
+
+		assertThat(filter.filterFiles(files)).hasSize(1);
+		assertThat(filter.accept(ftpFile1)).isTrue();
+	}
+
+}

spring-integration-sftp/src/main/java/org/springframework/integration/sftp/filters/SftpRecentFileListFilter.java

@@ -0,0 +1,48 @@
+/*
+ * Copyright 2025 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.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.integration.sftp.filters;
+
+import java.time.Duration;
+import java.time.Instant;
+
+import org.apache.sshd.sftp.client.SftpClient;
+
+import org.springframework.integration.file.filters.AbstractRecentFileListFilter;
+
+/**
+ * The {@link AbstractRecentFileListFilter} implementation for SFTP protocol.
+ *
+ * @author Artem Bilan
+ *
+ * @since 6.5
+ */
+public class SftpRecentFileListFilter extends AbstractRecentFileListFilter<SftpClient.DirEntry> {
+
+	public SftpRecentFileListFilter() {
+		super();
+	}
+
+	public SftpRecentFileListFilter(Duration age) {
+		super(age);
+	}
+
+	@Override
+	protected Instant getLastModified(SftpClient.DirEntry remoteFile) {
+		return remoteFile.getAttributes().getModifyTime().toInstant();
+	}
+
+}

spring-integration-sftp/src/test/java/org/springframework/integration/sftp/filters/SftpRecentFileListFilterTests.java

@@ -0,0 +1,59 @@
+/*
+ * Copyright 2025 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.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.integration.sftp.filters;
+
+import java.nio.file.attribute.FileTime;
+import java.time.Duration;
+import java.time.Instant;
+
+import org.apache.sshd.sftp.client.SftpClient;
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * @author Artem Bilan
+ *
+ * @since 6.5
+ */
+public class SftpRecentFileListFilterTests {
+
+	@Test
+	public void testAge() {
+		SftpRecentFileListFilter filter = new SftpRecentFileListFilter(Duration.ofHours(20));
+		SftpClient.Attributes attributes1 = new SftpClient.Attributes();
+		attributes1.setModifyTime(FileTime.from(Instant.now()));
+		SftpClient.Attributes attributes2 = new SftpClient.Attributes();
+		attributes2.setModifyTime(FileTime.from(Instant.now()));
+
+		SftpClient.DirEntry sftpFile1 = new SftpClient.DirEntry("foo", "foo", attributes1);
+		SftpClient.DirEntry sftpFile2 = new SftpClient.DirEntry("bar", "bar", attributes2);
+
+		SftpClient.DirEntry[] files = new SftpClient.DirEntry[] {sftpFile1, sftpFile2};
+
+		assertThat(filter.filterFiles(files)).hasSize(2);
+		assertThat(filter.accept(sftpFile1)).isTrue();
+		assertThat(filter.accept(sftpFile2)).isTrue();
+
+		FileTime fileTime = FileTime.from(Instant.now().minus(Duration.ofDays(1)));
+		sftpFile2.getAttributes().setModifyTime(fileTime);
+		assertThat(filter.filterFiles(files)).hasSize(1);
+		assertThat(filter.accept(sftpFile1)).isTrue();
+		assertThat(filter.accept(sftpFile2)).isFalse();
+	}
+
+}