Java Code Examples for org.apache.flink.core.fs.Path#toString()

@Test
public void testParametrizationDirectories() throws Exception {
	final JobID jid = new JobID();
	final Path checkpointPath = new Path(tmp.newFolder().toURI().toString());
	final Path savepointPath = new Path(tmp.newFolder().toURI().toString());

	MemoryStateBackend backend = new MemoryStateBackend(
			checkpointPath.toString(), savepointPath.toString());

	MemoryBackendCheckpointStorage storage =
			(MemoryBackendCheckpointStorage) backend.createCheckpointStorage(jid);

	assertTrue(storage.supportsHighlyAvailableStorage());
	assertTrue(storage.hasDefaultSavepointLocation());
	assertNotNull(storage.getDefaultSavepointDirectory());

	assertEquals(savepointPath, storage.getDefaultSavepointDirectory());
}
 

@Test
public void testParametrizationDirectories() throws Exception {
	final JobID jid = new JobID();
	final Path checkpointPath = new Path(tmp.newFolder().toURI().toString());
	final Path savepointPath = new Path(tmp.newFolder().toURI().toString());

	MemoryStateBackend backend = new MemoryStateBackend(
			checkpointPath.toString(), savepointPath.toString());

	MemoryBackendCheckpointStorage storage =
			(MemoryBackendCheckpointStorage) backend.createCheckpointStorage(jid);

	assertTrue(storage.supportsHighlyAvailableStorage());
	assertTrue(storage.hasDefaultSavepointLocation());
	assertNotNull(storage.getDefaultSavepointDirectory());

	assertEquals(savepointPath, storage.getDefaultSavepointDirectory());
}
 

@Test
public void testParametrizationDirectories() throws Exception {
	final JobID jid = new JobID();
	final Path checkpointPath = new Path(tmp.newFolder().toURI().toString());
	final Path savepointPath = new Path(tmp.newFolder().toURI().toString());

	MemoryStateBackend backend = new MemoryStateBackend(
			checkpointPath.toString(), savepointPath.toString());

	MemoryBackendCheckpointStorage storage =
			(MemoryBackendCheckpointStorage) backend.createCheckpointStorage(jid);

	assertTrue(storage.supportsHighlyAvailableStorage());
	assertTrue(storage.hasDefaultSavepointLocation());
	assertNotNull(storage.getDefaultSavepointDirectory());

	assertEquals(savepointPath, storage.getDefaultSavepointDirectory());
}
 

public VirtualFileServerHandler(Path path) throws IOException {
	this.path = path;
	if (!path.isAbsolute()) {
		throw new IllegalArgumentException("path must be absolute: " + path.toString());
	}
	this.fs = path.getFileSystem();
	if (!fs.exists(path) || fs.getFileStatus(path).isDir()) {
		throw new IllegalArgumentException("no such file: " + path.toString());
	}
}
 

private void testSavepoint(
		@Nullable Path savepointDir,
		@Nullable Path customDir,
		Path expectedParent) throws Exception {

	final CheckpointStorage storage = savepointDir == null ?
			createCheckpointStorage(randomTempPath()) :
			createCheckpointStorageWithSavepointDir(randomTempPath(), savepointDir);

	final String customLocation = customDir == null ? null : customDir.toString();

	final CheckpointStorageLocation savepointLocation =
			storage.initializeLocationForSavepoint(52452L, customLocation);

	final byte[] data = {77, 66, 55, 99, 88};

	final CompletedCheckpointStorageLocation completed;
	try (CheckpointMetadataOutputStream out = savepointLocation.createMetadataOutputStream()) {
		out.write(data);
		completed = out.closeAndFinalizeCheckpoint();
	}

	// we need to do this step to make sure we have a slash (or not) in the same way as the
	// expected path has it
	final Path normalizedWithSlash = Path.fromLocalFile(new File(new Path(completed.getExternalPointer()).getParent().getPath()));

	assertEquals(expectedParent, normalizedWithSlash);
	validateContents(completed.getMetadataHandle(), data);

	// validate that the correct directory was used
	FileStateHandle fileStateHandle = (FileStateHandle) completed.getMetadataHandle();

	// we need to recreate that path in the same way as the "expected path" (via File and URI) to make
	// sure the either both use '/' suffixes, or neither uses them (a bit of an annoying ambiguity)
	Path usedSavepointDir = new Path(new File(fileStateHandle.getFilePath().getParent().getParent().getPath()).toURI());

	assertEquals(expectedParent, usedSavepointDir);
}
 

@Test
public void testPointerPathResolution() throws Exception {
	final FileSystem fs = FileSystem.getLocalFileSystem();
	final Path metadataFile = new Path(Path.fromLocalFile(tmp.newFolder()), AbstractFsCheckpointStorage.METADATA_FILE_NAME);

	final String basePointer = metadataFile.getParent().toString();

	final String pointer1 = metadataFile.toString();
	final String pointer2 = metadataFile.getParent().toString();
	final String pointer3 = metadataFile.getParent().toString() + '/';

	// create the storage for some random checkpoint directory
	final CheckpointStorage storage = createCheckpointStorage(randomTempPath());

	final byte[] data = new byte[23686];
	new Random().nextBytes(data);
	try (FSDataOutputStream out = fs.create(metadataFile, WriteMode.NO_OVERWRITE)) {
		out.write(data);
	}

	CompletedCheckpointStorageLocation completed1 = storage.resolveCheckpoint(pointer1);
	CompletedCheckpointStorageLocation completed2 = storage.resolveCheckpoint(pointer2);
	CompletedCheckpointStorageLocation completed3 = storage.resolveCheckpoint(pointer3);

	assertEquals(basePointer, completed1.getExternalPointer());
	assertEquals(basePointer, completed2.getExternalPointer());
	assertEquals(basePointer, completed3.getExternalPointer());

	StreamStateHandle handle1 = completed1.getMetadataHandle();
	StreamStateHandle handle2 = completed2.getMetadataHandle();
	StreamStateHandle handle3 = completed3.getMetadataHandle();

	assertNotNull(handle1);
	assertNotNull(handle2);
	assertNotNull(handle3);

	validateContents(handle1, data);
	validateContents(handle2, data);
	validateContents(handle3, data);
}
 

public VirtualFileServerHandler(Path path) throws IOException {
	this.path = path;
	if (!path.isAbsolute()) {
		throw new IllegalArgumentException("path must be absolute: " + path.toString());
	}
	this.fs = path.getFileSystem();
	if (!fs.exists(path) || fs.getFileStatus(path).isDir()) {
		throw new IllegalArgumentException("no such file: " + path.toString());
	}
}
 

/**
 * Adds a path to the artifact server.
 * @param path the qualified FS path to serve (local, hdfs, etc).
 * @param remoteFile the remote path with which to locate the file.
 * @return the fully-qualified remote path to the file.
 * @throws MalformedURLException if the remote path is invalid.
 */
public synchronized URL addPath(Path path, Path remoteFile) throws IOException, MalformedURLException {
	if (paths.containsKey(remoteFile)) {
		throw new IllegalArgumentException("duplicate path registered");
	}
	if (remoteFile.isAbsolute()) {
		throw new IllegalArgumentException("not expecting an absolute path");
	}
	URL fileURL = new URL(baseURL, remoteFile.toString());
	router.addAny(fileURL.getPath(), new VirtualFileServerHandler(path));

	paths.put(remoteFile, fileURL);

	return fileURL;
}
 

private void testSavepoint(
		@Nullable Path savepointDir,
		@Nullable Path customDir,
		Path expectedParent) throws Exception {

	final CheckpointStorage storage = savepointDir == null ?
			createCheckpointStorage(randomTempPath()) :
			createCheckpointStorageWithSavepointDir(randomTempPath(), savepointDir);

	final String customLocation = customDir == null ? null : customDir.toString();

	final CheckpointStorageLocation savepointLocation =
			storage.initializeLocationForSavepoint(52452L, customLocation);

	final byte[] data = {77, 66, 55, 99, 88};

	final CompletedCheckpointStorageLocation completed;
	try (CheckpointMetadataOutputStream out = savepointLocation.createMetadataOutputStream()) {
		out.write(data);
		completed = out.closeAndFinalizeCheckpoint();
	}

	// we need to do this step to make sure we have a slash (or not) in the same way as the
	// expected path has it
	final Path normalizedWithSlash = Path.fromLocalFile(new File(new Path(completed.getExternalPointer()).getParent().getPath()));

	assertEquals(expectedParent, normalizedWithSlash);
	validateContents(completed.getMetadataHandle(), data);

	// validate that the correct directory was used
	FileStateHandle fileStateHandle = (FileStateHandle) completed.getMetadataHandle();

	// we need to recreate that path in the same way as the "expected path" (via File and URI) to make
	// sure the either both use '/' suffixes, or neither uses them (a bit of an annoying ambiguity)
	Path usedSavepointDir = new Path(new File(fileStateHandle.getFilePath().getParent().getParent().getPath()).toURI());

	assertEquals(expectedParent, usedSavepointDir);
}
 

@Test
public void testPointerPathResolution() throws Exception {
	final FileSystem fs = FileSystem.getLocalFileSystem();
	final Path metadataFile = new Path(Path.fromLocalFile(tmp.newFolder()), AbstractFsCheckpointStorage.METADATA_FILE_NAME);

	final String basePointer = metadataFile.getParent().toString();

	final String pointer1 = metadataFile.toString();
	final String pointer2 = metadataFile.getParent().toString();
	final String pointer3 = metadataFile.getParent().toString() + '/';

	// create the storage for some random checkpoint directory
	final CheckpointStorage storage = createCheckpointStorage(randomTempPath());

	final byte[] data = new byte[23686];
	new Random().nextBytes(data);
	try (FSDataOutputStream out = fs.create(metadataFile, WriteMode.NO_OVERWRITE)) {
		out.write(data);
	}

	CompletedCheckpointStorageLocation completed1 = storage.resolveCheckpoint(pointer1);
	CompletedCheckpointStorageLocation completed2 = storage.resolveCheckpoint(pointer2);
	CompletedCheckpointStorageLocation completed3 = storage.resolveCheckpoint(pointer3);

	assertEquals(basePointer, completed1.getExternalPointer());
	assertEquals(basePointer, completed2.getExternalPointer());
	assertEquals(basePointer, completed3.getExternalPointer());

	StreamStateHandle handle1 = completed1.getMetadataHandle();
	StreamStateHandle handle2 = completed2.getMetadataHandle();
	StreamStateHandle handle3 = completed3.getMetadataHandle();

	assertNotNull(handle1);
	assertNotNull(handle2);
	assertNotNull(handle3);

	validateContents(handle1, data);
	validateContents(handle2, data);
	validateContents(handle3, data);
}
 

public VirtualFileServerHandler(Path path) throws IOException {
	this.path = path;
	if (!path.isAbsolute()) {
		throw new IllegalArgumentException("path must be absolute: " + path.toString());
	}
	this.fs = path.getFileSystem();
	if (!fs.exists(path) || fs.getFileStatus(path).isDir()) {
		throw new IllegalArgumentException("no such file: " + path.toString());
	}
}
 

/**
 * Adds a path to the artifact server.
 * @param path the qualified FS path to serve (local, hdfs, etc).
 * @param remoteFile the remote path with which to locate the file.
 * @return the fully-qualified remote path to the file.
 * @throws MalformedURLException if the remote path is invalid.
 */
public synchronized URL addPath(Path path, Path remoteFile) throws IOException, MalformedURLException {
	if (paths.containsKey(remoteFile)) {
		throw new IllegalArgumentException("duplicate path registered");
	}
	if (remoteFile.isAbsolute()) {
		throw new IllegalArgumentException("not expecting an absolute path");
	}
	URL fileURL = new URL(baseURL, remoteFile.toString());
	router.addAny(fileURL.getPath(), new VirtualFileServerHandler(path));

	paths.put(remoteFile, fileURL);

	return fileURL;
}
 

@Test
public void testStartPythonProcess() {
	PythonEnvUtils.PythonEnvironment pythonEnv = new PythonEnvUtils.PythonEnvironment();
	pythonEnv.workingDirectory = tmpDirPath.toString();
	pythonEnv.pythonPath = tmpDirPath.toString();
	List<String> commands = new ArrayList<>();
	Path pyPath = new Path(tmpDirPath, "word_count.py");
	try {
		tmpDirFs.create(pyPath, FileSystem.WriteMode.OVERWRITE);
		File pyFile = new File(pyPath.toString());
		String pyProgram = "#!/usr/bin/python\n" +
			"# -*- coding: UTF-8 -*-\n" +
			"import sys\n" +
			"\n" +
			"if __name__=='__main__':\n" +
			"\tfilename = sys.argv[1]\n" +
			"\tfo = open(filename, \"w\")\n" +
			"\tfo.write( \"hello world\")\n" +
			"\tfo.close()";
		Files.write(pyFile.toPath(), pyProgram.getBytes(), StandardOpenOption.WRITE);
		Path result = new Path(tmpDirPath, "word_count_result.txt");
		commands.add(pyFile.getName());
		commands.add(result.getName());
		Process pythonProcess = PythonEnvUtils.startPythonProcess(pythonEnv, commands);
		int exitCode = pythonProcess.waitFor();
		if (exitCode != 0) {
			throw new RuntimeException("Python process exits with code: " + exitCode);
		}
		String cmdResult = new String(Files.readAllBytes(new File(result.toString()).toPath()));
		Assert.assertEquals(cmdResult, "hello world");
		pythonProcess.destroyForcibly();
		tmpDirFs.delete(pyPath, true);
		tmpDirFs.delete(result, true);
	} catch (IOException | InterruptedException e) {
		throw new RuntimeException("test start Python process failed " + e.getMessage());
	}
}
 

private void testSavepoint(
		@Nullable Path savepointDir,
		@Nullable Path customDir,
		Path expectedParent) throws Exception {

	final CheckpointStorage storage = savepointDir == null ?
			createCheckpointStorage(randomTempPath()) :
			createCheckpointStorageWithSavepointDir(randomTempPath(), savepointDir);

	final String customLocation = customDir == null ? null : customDir.toString();

	final CheckpointStorageLocation savepointLocation =
			storage.initializeLocationForSavepoint(52452L, customLocation);

	final byte[] data = {77, 66, 55, 99, 88};

	final CompletedCheckpointStorageLocation completed;
	try (CheckpointMetadataOutputStream out = savepointLocation.createMetadataOutputStream()) {
		out.write(data);
		completed = out.closeAndFinalizeCheckpoint();
	}

	// we need to do this step to make sure we have a slash (or not) in the same way as the
	// expected path has it
	final Path normalizedWithSlash = Path.fromLocalFile(new File(new Path(completed.getExternalPointer()).getParent().getPath()));

	assertEquals(expectedParent, normalizedWithSlash);
	validateContents(completed.getMetadataHandle(), data);

	// validate that the correct directory was used
	FileStateHandle fileStateHandle = (FileStateHandle) completed.getMetadataHandle();

	// we need to recreate that path in the same way as the "expected path" (via File and URI) to make
	// sure the either both use '/' suffixes, or neither uses them (a bit of an annoying ambiguity)
	Path usedSavepointDir = new Path(new File(fileStateHandle.getFilePath().getParent().getParent().getPath()).toURI());

	assertEquals(expectedParent, usedSavepointDir);
}
 

@Test
public void testPointerPathResolution() throws Exception {
	final FileSystem fs = FileSystem.getLocalFileSystem();
	final Path metadataFile = new Path(Path.fromLocalFile(tmp.newFolder()), AbstractFsCheckpointStorage.METADATA_FILE_NAME);

	final String basePointer = metadataFile.getParent().toString();

	final String pointer1 = metadataFile.toString();
	final String pointer2 = metadataFile.getParent().toString();
	final String pointer3 = metadataFile.getParent().toString() + '/';

	// create the storage for some random checkpoint directory
	final CheckpointStorage storage = createCheckpointStorage(randomTempPath());

	final byte[] data = new byte[23686];
	new Random().nextBytes(data);
	try (FSDataOutputStream out = fs.create(metadataFile, WriteMode.NO_OVERWRITE)) {
		out.write(data);
	}

	CompletedCheckpointStorageLocation completed1 = storage.resolveCheckpoint(pointer1);
	CompletedCheckpointStorageLocation completed2 = storage.resolveCheckpoint(pointer2);
	CompletedCheckpointStorageLocation completed3 = storage.resolveCheckpoint(pointer3);

	assertEquals(basePointer, completed1.getExternalPointer());
	assertEquals(basePointer, completed2.getExternalPointer());
	assertEquals(basePointer, completed3.getExternalPointer());

	StreamStateHandle handle1 = completed1.getMetadataHandle();
	StreamStateHandle handle2 = completed2.getMetadataHandle();
	StreamStateHandle handle3 = completed3.getMetadataHandle();

	assertNotNull(handle1);
	assertNotNull(handle2);
	assertNotNull(handle3);

	validateContents(handle1, data);
	validateContents(handle2, data);
	validateContents(handle3, data);
}
 

@Override
public void open(int taskNumber, int numTasks) throws IOException {
	if (taskNumber < 0 || numTasks < 1) {
		throw new IllegalArgumentException("TaskNumber: " + taskNumber + ", numTasks: " + numTasks);
	}
	
	if (LOG.isDebugEnabled()) {
		LOG.debug("Opening stream for output (" + (taskNumber+1) + "/" + numTasks + "). WriteMode=" + writeMode +
				", OutputDirectoryMode=" + outputDirectoryMode);
	}
	
	Path p = this.outputFilePath;
	if (p == null) {
		throw new IOException("The file path is null.");
	}
	
	final FileSystem fs = p.getFileSystem();

	// if this is a local file system, we need to initialize the local output directory here
	if (!fs.isDistributedFS()) {
		
		if (numTasks == 1 && outputDirectoryMode == OutputDirectoryMode.PARONLY) {
			// output should go to a single file
			
			// prepare local output path. checks for write mode and removes existing files in case of OVERWRITE mode
			if(!fs.initOutPathLocalFS(p, writeMode, false)) {
				// output preparation failed! Cancel task.
				throw new IOException("Output path '" + p.toString() + "' could not be initialized. Canceling task...");
			}
		}
		else {
			// numTasks > 1 || outDirMode == OutputDirectoryMode.ALWAYS
			
			if(!fs.initOutPathLocalFS(p, writeMode, true)) {
				// output preparation failed! Cancel task.
				throw new IOException("Output directory '" + p.toString() + "' could not be created. Canceling task...");
			}
		}
	}



	// Suffix the path with the parallel instance index, if needed
	this.actualFilePath = (numTasks > 1 || outputDirectoryMode == OutputDirectoryMode.ALWAYS) ? p.suffix("/" + getDirectoryFileName(taskNumber)) : p;

	// create output file
	this.stream = fs.create(this.actualFilePath, writeMode);
	
	// at this point, the file creation must have succeeded, or an exception has been thrown
	this.fileCreated = true;
}
 

/**
 * Prepares PythonEnvironment to start python process.
 *
 * @param pythonLibFiles The dependent Python files.
 * @return PythonEnvironment the Python environment which will be executed in Python process.
 */
public static PythonEnvironment preparePythonEnvironment(List<Path> pythonLibFiles) throws IOException {
	PythonEnvironment env = new PythonEnvironment();

	// 1. setup temporary local directory for the user files
	String tmpDir = System.getProperty("java.io.tmpdir") +
		File.separator + "pyflink" + File.separator + UUID.randomUUID();

	Path tmpDirPath = new Path(tmpDir);
	FileSystem fs = tmpDirPath.getFileSystem();
	if (fs.exists(tmpDirPath)) {
		fs.delete(tmpDirPath, true);
	}
	fs.mkdirs(tmpDirPath);

	env.workingDirectory = tmpDirPath.toString();

	StringBuilder pythonPathEnv = new StringBuilder();

	pythonPathEnv.append(env.workingDirectory);

	// 2. create symbolLink in the working directory for the pyflink dependency libs.
	List<java.nio.file.Path> pythonLibs = getLibFiles(FLINK_OPT_DIR_PYTHON);
	for (java.nio.file.Path libPath : pythonLibs) {
		java.nio.file.Path symbolicLinkFilePath = FileSystems.getDefault().getPath(env.workingDirectory,
			libPath.getFileName().toString());
		createSymbolicLinkForPyflinkLib(libPath, symbolicLinkFilePath);
		pythonPathEnv.append(File.pathSeparator);
		pythonPathEnv.append(symbolicLinkFilePath.toString());
	}

	// 3. copy relevant python files to tmp dir and set them in PYTHONPATH.
	for (Path pythonFile : pythonLibFiles) {
		String sourceFileName = pythonFile.getName();
		Path targetPath = new Path(tmpDirPath, sourceFileName);
		FileUtils.copy(pythonFile, targetPath, true);
		String targetFileNames = Files.walk(Paths.get(targetPath.toString()))
			.filter(Files::isRegularFile)
			.filter(f -> !f.toString().endsWith(".py"))
			.map(java.nio.file.Path::toString)
			.collect(Collectors.joining(File.pathSeparator));
		pythonPathEnv.append(File.pathSeparator);
		pythonPathEnv.append(targetFileNames);
	}

	// 4. add the parent directory to PYTHONPATH for files suffixed with .py
	String pyFileParents = Files.walk(Paths.get(tmpDirPath.toString()))
		.filter(file -> file.toString().endsWith(".py"))
		.map(java.nio.file.Path::getParent)
		.distinct()
		.map(java.nio.file.Path::toString)
		.collect(Collectors.joining(File.pathSeparator));
	if (!StringUtils.isNullOrWhitespaceOnly(pyFileParents)) {
		pythonPathEnv.append(File.pathSeparator);
		pythonPathEnv.append(pyFileParents);
	}

	env.pythonPath = pythonPathEnv.toString();
	return env;
}
 

@Override
public void open(int taskNumber, int numTasks) throws IOException {
	if (taskNumber < 0 || numTasks < 1) {
		throw new IllegalArgumentException("TaskNumber: " + taskNumber + ", numTasks: " + numTasks);
	}
	
	if (LOG.isDebugEnabled()) {
		LOG.debug("Opening stream for output (" + (taskNumber+1) + "/" + numTasks + "). WriteMode=" + writeMode +
				", OutputDirectoryMode=" + outputDirectoryMode);
	}
	
	Path p = this.outputFilePath;
	if (p == null) {
		throw new IOException("The file path is null.");
	}
	
	final FileSystem fs = p.getFileSystem();

	// if this is a local file system, we need to initialize the local output directory here
	if (!fs.isDistributedFS()) {
		
		if (numTasks == 1 && outputDirectoryMode == OutputDirectoryMode.PARONLY) {
			// output should go to a single file
			
			// prepare local output path. checks for write mode and removes existing files in case of OVERWRITE mode
			if(!fs.initOutPathLocalFS(p, writeMode, false)) {
				// output preparation failed! Cancel task.
				throw new IOException("Output path '" + p.toString() + "' could not be initialized. Canceling task...");
			}
		}
		else {
			// numTasks > 1 || outDirMode == OutputDirectoryMode.ALWAYS
			
			if(!fs.initOutPathLocalFS(p, writeMode, true)) {
				// output preparation failed! Cancel task.
				throw new IOException("Output directory '" + p.toString() + "' could not be created. Canceling task...");
			}
		}
	}



	// Suffix the path with the parallel instance index, if needed
	this.actualFilePath = (numTasks > 1 || outputDirectoryMode == OutputDirectoryMode.ALWAYS) ? p.suffix("/" + getDirectoryFileName(taskNumber)) : p;

	// create output file
	this.stream = fs.create(this.actualFilePath, writeMode);
	
	// at this point, the file creation must have succeeded, or an exception has been thrown
	this.fileCreated = true;
}
 

private static void assertPathsEqual(Path expected, Path actual) {
	final Path reNormalizedExpected = new Path(expected.toString());
	final Path reNormalizedActual = new Path(actual.toString());
	assertEquals(reNormalizedExpected, reNormalizedActual);
}
 

@Override
public void open(int taskNumber, int numTasks) throws IOException {
	if (taskNumber < 0 || numTasks < 1) {
		throw new IllegalArgumentException("TaskNumber: " + taskNumber + ", numTasks: " + numTasks);
	}
	
	if (LOG.isDebugEnabled()) {
		LOG.debug("Opening stream for output (" + (taskNumber+1) + "/" + numTasks + "). WriteMode=" + writeMode +
				", OutputDirectoryMode=" + outputDirectoryMode);
	}
	
	Path p = this.outputFilePath;
	if (p == null) {
		throw new IOException("The file path is null.");
	}
	
	final FileSystem fs = p.getFileSystem();

	// if this is a local file system, we need to initialize the local output directory here
	if (!fs.isDistributedFS()) {
		
		if (numTasks == 1 && outputDirectoryMode == OutputDirectoryMode.PARONLY) {
			// output should go to a single file
			
			// prepare local output path. checks for write mode and removes existing files in case of OVERWRITE mode
			if(!fs.initOutPathLocalFS(p, writeMode, false)) {
				// output preparation failed! Cancel task.
				throw new IOException("Output path '" + p.toString() + "' could not be initialized. Canceling task...");
			}
		}
		else {
			// numTasks > 1 || outDirMode == OutputDirectoryMode.ALWAYS
			
			if(!fs.initOutPathLocalFS(p, writeMode, true)) {
				// output preparation failed! Cancel task.
				throw new IOException("Output directory '" + p.toString() + "' could not be created. Canceling task...");
			}
		}
	}



	// Suffix the path with the parallel instance index, if needed
	this.actualFilePath = (numTasks > 1 || outputDirectoryMode == OutputDirectoryMode.ALWAYS) ? p.suffix("/" + getDirectoryFileName(taskNumber)) : p;

	// create output file
	this.stream = fs.create(this.actualFilePath, writeMode);
	
	// at this point, the file creation must have succeeded, or an exception has been thrown
	this.fileCreated = true;
}