Package io.camunda.zeebe.util

Class FileUtil

java.lang.Object

io.camunda.zeebe.util.FileUtil

public final class FileUtil
extends Object

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static final class	FileUtil.SnapshotCopier

Method Summary

Modifier and Type	Method	Description
static void	copySnapshot(Path snapshotDirectory, Path runtimeDirectory)
static void	deleteFolder(String path)
static void	deleteFolder(Path folder)
static void	deleteFolderContents(Path folder)	A variant of deleteFolder(String)} which deletes everything but the top level directory.
static void	deleteFolderIfExists(Path folder)	A variant of deleteFolder(Path), which ignores missing files.
static void	ensureDirectoryExists(Path directory)
static void	flush(Path path)	Ensures updates to the given path are flushed to disk, with the same guarantees as FileChannel.force(boolean).
static void	flushDirectory(Path path)	This method flushes the given directory.
static boolean	isEmpty(Path path)	Return true if directory does not exists, or if it is empty.
static void	moveDurably(Path source, Path target, CopyOption... options)	Moves the given source file to the target location, flushing the target's parent directory afterwards to guarantee that the file will be visible and avoid the classic 0-length problem.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Details

flush

public static void flush(Path path)
                  throws IOException

Ensures updates to the given path are flushed to disk, with the same guarantees as FileChannel.force(boolean). This can be used for files only; for directories, call flushDirectory(Path). Note that if you already have a file channel open, then use the FileChannel.force(boolean) method directly.

Parameters:

path - the path to synchronize

Throws:

IOException - can be thrown on opening and on flushing the file

flushDirectory

public static void flushDirectory(Path path)
                           throws IOException

This method flushes the given directory. Note that on Windows this is a no-op, as Windows does not allow to flush directories except when opening the sys handle with a specific backup flag, which is not possible to do without custom JNI code. However, as the main use case here is for durability to sync the parent directory after creating a new file or renaming it, this is safe to do as Windows (or rather NTFS) does not need this.

Parameters:

path - the path to synchronize

Throws:

IOException - can be thrown on opening and on flushing the file

moveDurably

public static void moveDurably(Path source,
 Path target,
 CopyOption... options)
                        throws IOException

Moves the given source file to the target location, flushing the target's parent directory afterwards to guarantee that the file will be visible and avoid the classic 0-length problem.

Parameters:

source - the file or directory to move

target - the new path the file or directory should have after

options - copy options, e.g. StandardCopyOption

Throws:

IOException - on either move or flush error

deleteFolder

public static void deleteFolder(String path)
                         throws IOException

Throws:

IOException

ensureDirectoryExists

public static void ensureDirectoryExists(Path directory)
                                  throws IOException

Throws:

IOException

deleteFolderIfExists

public static void deleteFolderIfExists(Path folder)
                                 throws IOException

A variant of deleteFolder(Path), which ignores missing files. Inspired from Files.deleteIfExists(Path) which is implemented in much the same way. To be preferred over deleteFolder(Path) preceded by a Files.exists(Path, LinkOption...), as that is more prone to race conditions.

Parameters:

folder - the directory to delete (if or any of its files exists)

Throws:

IOException - on failure to scan the directory and/or delete the file

deleteFolderContents

public static void deleteFolderContents(Path folder)
                                 throws IOException

A variant of deleteFolder(String)} which deletes everything but the top level directory. This can be useful for deleting everything inside a folder that is itself not delete-able, for example because the folder is mounted as a docker volume

Parameters:

folder - the directory which contents should be deleted

Throws:

IOException - on failure to scan the directory and/or delete the file

deleteFolder

public static void deleteFolder(Path folder)
                         throws IOException

Throws:

IOException

copySnapshot

public static void copySnapshot(Path snapshotDirectory,
 Path runtimeDirectory)
                         throws Exception

Throws:

Exception

isEmpty

public static boolean isEmpty(Path path)
                       throws IOException

Return true if directory does not exists, or if it is empty. Returns false if the path is not a directory

Throws:

IOException