Package com.inductiveautomation.ignition.common.util

Class 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 Description
      SafeFileOutputStream​(java.io.File destinationFile, java.io.File backupFile)  

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      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 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.lang.AutoCloseable
        Specified by:
        close in interface java.io.Closeable
        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