This option is meaningful only if the FileAppender opens the file. 

 public FileAppender() 
{

}

The default constructor does not do anything.

 public FileAppender(Layout layout,
    String filename) throws IOException 
{
    this(layout, filename, true);
}

Instantiate a FileAppender and open the file designated by filename. The opened filename will become the output destination for this appender.

The file will be appended to.

 public FileAppender(Layout layout,
    String filename,
    boolean append) throws IOException 
{
    this.layout = layout;
    this.setFile(filename, append, false, bufferSize);
}

Instantiate a FileAppender and open the file designated by filename. The opened filename will become the output destination for this appender.

If the append parameter is true, the file will be appended to. Otherwise, the file designated by filename will be truncated before being opened.

 public FileAppender(Layout layout,
    String filename,
    boolean append,
    boolean bufferedIO,
    int bufferSize) throws IOException 
{
    this.layout = layout;
    this.setFile(filename, append, bufferedIO, bufferSize);
}

Instantiate a FileAppender and open the file designated by filename. The opened filename will become the output destination for this appender.

If the append parameter is true, the file will be appended to. Otherwise, the file designated by filename will be truncated before being opened.

If the bufferedIO parameter is true, then buffered IO will be used to write to the output file.

 public  void activateOptions() 
{
    if(fileName != null) {
      try {
	setFile(fileName, fileAppend, bufferedIO, bufferSize);
      }
      catch(java.io.IOException e) {
	errorHandler.error("setFile("+fileName+","+fileAppend+") call failed.",
			   e, ErrorCode.FILE_OPEN_FAILURE);
      }
    } else {
      //LogLog.error("File option not set for appender ["+name+"].");
      LogLog.warn("File option not set for appender ["+name+"].");
      LogLog.warn("Are you using FileAppender instead of ConsoleAppender?");
    }
}

If the value of File is not null, then #setFile is called with the values of File and Append properties.

 protected  void closeFile() 
{
    if(this.qw != null) {
      try {
	this.qw.close();
      }
      catch(java.io.IOException e) {
	// Exceptionally, it does not make sense to delegate to an
	// ErrorHandler. Since a closed appender is basically dead.
	LogLog.error("Could not close " + qw, e);
      }
    }
}

Closes the previously opened file.

 public boolean getAppend() 
{
    return fileAppend;
}

Returns the value of the Append option.

 public int getBufferSize() 
{
    return this.bufferSize;
}

Get the size of the IO buffer.

 public boolean getBufferedIO() 
{
    return this.bufferedIO;
}

Get the value of the BufferedIO option.

BufferedIO will significatnly increase performance on heavily loaded systems.

 public String getFile() 
{
    return fileName;
}

Returns the value of the File option.

 protected  void reset() 
{
    closeFile();
    this.fileName = null;
    super.reset();
}

Close any previously opened file and call the parent's reset.

 public  void setAppend(boolean flag) 
{
    fileAppend = flag;
}

The Append option takes a boolean value. It is set to true by default. If true, then File will be opened in append mode by setFile (see above). Otherwise, setFile will open File in truncate mode.

Note: Actual opening of the file is made when #activateOptions is called, not when the options are set.

 public  void setBufferSize(int bufferSize) 
{
    this.bufferSize = bufferSize;
}

Set the size of the IO buffer.

 public  void setBufferedIO(boolean bufferedIO) 
{
    this.bufferedIO = bufferedIO;
    if(bufferedIO) {
      immediateFlush = false;
    }
}

The BufferedIO option takes a boolean value. It is set to false by default. If true, then File will be opened and the resulting java.io.Writer wrapped around a BufferedWriter . BufferedIO will significatnly increase performance on heavily loaded systems.

 public  void setFile(String file) 
{
    // Trim spaces from both ends. The users probably does not want
    // trailing spaces in file names.
    String val = file.trim();
    fileName = val;
}

The File property takes a string value which should be the name of the file to append to.

Note that the special values "System.out" or "System.err" are no longer honored.

Note: Actual opening of the file is made when #activateOptions is called, not when the options are set.

 public synchronized  void setFile(String fileName,
    boolean append,
    boolean bufferedIO,
    int bufferSize) throws IOException 
{
    LogLog.debug("setFile called: "+fileName+", "+append);
    // It does not make sense to have immediate flush and bufferedIO.
    if(bufferedIO) {
      setImmediateFlush(false);
    }
    reset();
    FileOutputStream ostream = null;
    try {
          //
          //   attempt to create file
          //
          ostream = new FileOutputStream(fileName, append);
    } catch(FileNotFoundException ex) {
          //
          //   if parent directory does not exist then
          //      attempt to create it and try to create file
          //      see bug 9150
          //
          String parentName = new File(fileName).getParent();
          if (parentName != null) {
             File parentDir = new File(parentName);
             if(!parentDir.exists() && parentDir.mkdirs()) {
                ostream = new FileOutputStream(fileName, append);
             } else {
                throw ex;
             }
          } else {
             throw ex;
          }
    }
    Writer fw = createWriter(ostream);
    if(bufferedIO) {
      fw = new BufferedWriter(fw, bufferSize);
    }
    this.setQWForFiles(fw);
    this.fileName = fileName;
    this.fileAppend = append;
    this.bufferedIO = bufferedIO;
    this.bufferSize = bufferSize;
    writeHeader();
    LogLog.debug("setFile ended");
}

Sets and opens the file where the log output will go. The specified file must be writable.

If there was already an opened file, then the previous file is closed first.

Do not use this method directly. To configure a FileAppender or one of its subclasses, set its properties one by one and then call activateOptions.

 protected  void setQWForFiles(Writer writer) 
{
     this.qw = new QuietWriter(writer, errorHandler);
}

Sets the quiet writer being used. This method is overriden by RollingFileAppender .