added in version 22.1.0
belongs to Maven artifact


public class AtomicFile
extends Object


Static library support version of the framework's AtomicFile, a helper class for performing atomic operations on a file by creating a backup file until a write has successfully completed.

Atomic file guarantees file integrity by ensuring that a file has been completely written and sync'd to disk before removing its backup. As long as the backup file exists, the original file is considered to be invalid (left over from a previous attempt to write the file).

Atomic file does not confer any file locking semantics. Do not use this class when the file may be accessed or modified concurrently by multiple threads or processes. The caller is responsible for ensuring appropriate mutual exclusion invariants whenever it accesses the file.


Public constructors

AtomicFile(File baseName)

Create a new AtomicFile for a file located at the given File path.

Public methods

void delete()

Delete the atomic file.

void failWrite(FileOutputStream str)

Call when you have failed for some reason at writing to the stream returned by startWrite().

void finishWrite(FileOutputStream str)

Call when you have successfully finished writing to the stream returned by startWrite().

File getBaseFile()

Return the path to the base file.

FileInputStream openRead()

Open the atomic file for reading.

byte[] readFully()

A convenience for openRead() that also reads all of the file contents into a byte array which is returned.

FileOutputStream startWrite()

Start a new write operation on the file.

Inherited methods

From class java.lang.Object

Public constructors


added in version 22.1.0
AtomicFile (File baseName)

Create a new AtomicFile for a file located at the given File path. The secondary backup file will be the same file path with ".bak" appended.

baseName File

Public methods


added in version 22.1.0
void delete ()

Delete the atomic file. This deletes both the base and backup files.


added in version 22.1.0