com.inductiveautomation.ignition.common.util

Class SafeFileOutputStream

java.lang.Object

java.io.OutputStream

com.inductiveautomation.ignition.common.util.SafeFileOutputStream

All Implemented Interfaces:

java.io.Closeable, java.io.Flushable, java.lang.AutoCloseable

public class SafeFileOutputStream
extends java.io.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 and Description
SafeFileOutputStream(java.io.File destinationFile, java.io.File backupFile)

Method Summary

Modifier and Type	Method and 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.lang.Object

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

Constructor Detail

SafeFileOutputStream

public SafeFileOutputStream(java.io.File destinationFile,
                            java.io.File backupFile)
                     throws java.io.IOException

Throws:

java.io.IOException

Method Detail

close

public void close()
           throws java.io.IOException

Specified by:

close in interface java.io.Closeable

Specified by:

close in interface java.lang.AutoCloseable

Overrides:

close in class java.io.OutputStream

Throws:

java.io.IOException

flush

public void flush()
           throws java.io.IOException

Specified by:

flush in interface java.io.Flushable

Overrides:

flush in class java.io.OutputStream

Throws:

java.io.IOException

write

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

Overrides:

write in class java.io.OutputStream

Throws:

java.io.IOException

write

public void write(byte[] b)
           throws java.io.IOException

Overrides:

write in class java.io.OutputStream

Throws:

java.io.IOException

write

public void write(int b)
           throws java.io.IOException

Specified by:

write in class java.io.OutputStream

Throws:

java.io.IOException