Package com.inductiveautomation.ignition.common.util

Class SafeFileOutputStream

java.lang.Object

java.io.OutputStream

com.inductiveautomation.ignition.common.util.SafeFileOutputStream

All Implemented Interfaces:

Closeable, Flushable, AutoCloseable

public class SafeFileOutputStream
extends OutputStream

A FileOutputStream that implements a two-stage write process, and additionaly copies any existing file to a backup location. This ensures that no matter what (software or hardware failures), there is always a valid (non-corrupt) copy of the destination file. More formally, the logic is as follows.

• As write() is called on the SafeFileOutputStream instance, information is written to a temporary file, obtained by File.createTempFile().
• When close() is called, the destination file (if it exists), is renamed to the backup file
• Then the temp file is renamed to the destination file

Constructor Summary

Constructors

Constructor	Description
SafeFileOutputStream(File destinationFile, File backupFile)

Method Summary

Modifier and Type	Method	Description
void	close()
void	flush()
void	write(byte[] b)
void	write(byte[] b, int off, int len)
void	write(int b)

Methods inherited from class java.io.OutputStream

nullOutputStream

Methods inherited from class java.lang.Object

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

Constructor Details

SafeFileOutputStream

public SafeFileOutputStream(File destinationFile,
 File backupFile)
                     throws IOException

Throws:

IOException

Method Details

close

public void close()
           throws IOException

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

Overrides:

close in class OutputStream

Throws:

IOException

flush

public void flush()
           throws IOException

Specified by:

flush in interface Flushable

Overrides:

flush in class OutputStream

Throws:

IOException

write

public void write(byte[] b,
 int off,
 int len)
           throws IOException

Overrides:

write in class OutputStream

Throws:

IOException

write

public void write(byte[] b)
           throws IOException

Overrides:

write in class OutputStream

Throws:

IOException

write

public void write(int b)
           throws IOException

Specified by:

write in class OutputStream

Throws:

IOException