IN PROGRESS - issue INT-546: FileListFilters throw an IllegalArgumentException when the polled directory is empty

http://jira.springframework.org/browse/INT-546

org.springframework.integration.file/src/main/java/org/springframework/integration/file/AbstractFileListFilter.java

@@ -23,23 +23,25 @@ import java.util.List;
 import org.springframework.util.Assert;
 
 /**
- * A convenience base class for any {@link FileListFilter} whose criteria can
- * be evaluated against each File in isolation. If the entire List of files is
+ * A convenience base class for any {@link FileListFilter} whose criteria can be
+ * evaluated against each File in isolation. If the entire List of files is
  * required for evaluation, implement the FileListFilter interface directly.
  * 
  * @author Mark Fisher
+ * @author Iwein Fuld
  */
 public abstract class AbstractFileListFilter implements FileListFilter {
 
 	/**
-	 * Returns the list of files that are accepted by this filter.
+	 * {@inheritDoc}
 	 */
 	public final List<File> filterFiles(File[] files) {
-		Assert.notNull(files,"'files' should not be null.");
 		List<File> accepted = new ArrayList<File>();
-		for (File file : files) {
-			if (this.accept(file)) {
-				accepted.add(file);
+		if (files != null) {
+			for (File file : files) {
+				if (this.accept(file)) {
+					accepted.add(file);
+				}
 			}
 		}
 		return accepted;

org.springframework.integration.file/src/main/java/org/springframework/integration/file/FileListFilter.java

@@ -27,7 +27,8 @@ import java.util.List;
 public interface FileListFilter {
 
 	/**
-	 * Filters out files and returns the files that are left in a list.
+	 * Filters out files and returns the files that are left in a list, or an
+	 * empty list when a null is passed in.
 	 */
 	List<File> filterFiles(File[] files);
 

org.springframework.integration.file/src/test/java/org/springframework/integration/file/FileReadingMessageSourceIntegrationTests.java

@@ -110,6 +110,14 @@ public class FileReadingMessageSourceIntegrationTests {
 		assertNotSame(received1 + " == " + received3, received1, received3);
 		assertNotSame(received2 + " == " + received3, received2, received3);
 	}
+	
+	@Test
+	public void inputDirExhausted() throws Exception {
+		assertNotNull(pollableFileSource.receive());
+		assertNotNull(pollableFileSource.receive());
+		assertNotNull(pollableFileSource.receive());
+		assertNull(pollableFileSource.receive());
+	}
 
 	@Test(timeout = 6000)
 	@Repeat(10)

org.springframework.integration.file/src/test/java/org/springframework/integration/file/FileToChannelIntegrationTests-context.xml

@@ -0,0 +1,44 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<beans xmlns:file="http://www.springframework.org/schema/integration/file"
+	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.springframework.org/schema/beans"
+	xmlns:si="http://www.springframework.org/schema/integration"
+	xsi:schemaLocation="http://www.springframework.org/schema/beans
+			http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
+			http://www.springframework.org/schema/integration
+			http://www.springframework.org/schema/integration/spring-integration-1.0.xsd
+			http://www.springframework.org/schema/integration/file
+			http://www.springframework.org/schema/integration/file/spring-integration-file-1.0.xsd">
+
+	<!-- under test -->
+	<file:inbound-channel-adapter
+		directory="file:${java.io.tmpdir}/FileToChannelIntegrationTests"
+		channel="fileMessages" filter="compositeFilter" />
+
+	<si:channel id="fileMessages">
+		<si:queue capacity="10" />
+	</si:channel>
+
+	<!-- customized filter -->
+	<bean id="compositeFilter"
+		class="org.springframework.integration.file.CompositeFileListFilter">
+		<constructor-arg>
+			<list>
+				<bean
+					class="org.springframework.integration.file.AcceptOnceFileListFilter" />
+				<bean class="org.springframework.integration.file.TestFileListFilter" />
+				<bean
+					class="org.springframework.integration.file.PatternMatchingFileListFilter">
+					<constructor-arg value="^test.*$" />
+				</bean>
+			</list>
+		</constructor-arg>
+	</bean>
+
+	<si:poller default="true">
+		<si:interval-trigger interval="10" />
+	</si:poller>
+	
+	<bean
+		class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer" />
+
+</beans>

org.springframework.integration.file/src/test/java/org/springframework/integration/file/FileToChannelIntegrationTests.java

@@ -0,0 +1,75 @@
+package org.springframework.integration.file;
+
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertNull;
+
+import java.io.File;
+
+import org.junit.After;
+import org.junit.AfterClass;
+import org.junit.Before;
+import org.junit.BeforeClass;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.integration.channel.PollableChannel;
+import org.springframework.integration.core.Message;
+import org.springframework.test.context.ContextConfiguration;
+import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
+
+@ContextConfiguration
+@RunWith(SpringJUnit4ClassRunner.class)
+public class FileToChannelIntegrationTests {
+	private static File inputDir;
+
+	@Autowired
+	PollableChannel fileMessages;
+
+	@BeforeClass
+	public static void setupInputDir() {
+		inputDir = new File(System.getProperty("java.io.tmpdir") + "/"
+				+ FileToChannelIntegrationTests.class.getSimpleName());
+		inputDir.mkdir();
+	}
+
+	@After
+	public void cleanoutInputDir() throws Exception {
+		File[] listFiles = inputDir.listFiles();
+		for (int i = 0; i < listFiles.length; i++) {
+			listFiles[i].delete();
+		}
+	}
+
+	@AfterClass
+	public static void removeInputDir() throws Exception {
+		inputDir.delete();
+	}
+
+	@Test(timeout = 2000)
+	public void fileMessageToChannel() throws Exception {
+		File.createTempFile("test", null, inputDir).setLastModified(System.currentTimeMillis() - 1000);
+		Message<File> received = receiveFileMessage();
+		while (received == null) {
+			Thread.sleep(50);
+			received = receiveFileMessage();
+		}
+		assertNotNull(received.getPayload());
+	}
+
+	@SuppressWarnings("unchecked")
+	private Message<File> receiveFileMessage() {
+		return (Message<File>) fileMessages.receive();
+	}
+
+	@Test(timeout = 2000)
+	public void directoryExhaustion() throws Exception {
+		File.createTempFile("test", null, inputDir).setLastModified(System.currentTimeMillis() - 1000);
+		Message<File> received = receiveFileMessage();
+		while (received == null) {
+			Thread.sleep(5);
+			received = receiveFileMessage();
+		}
+		assertNotNull(received.getPayload());
+		assertNull(fileMessages.receive(200));
+	}
+}