public DeferredFileOutputStream(int threshold,
    File outputFile) 
{
        super(threshold);
        this.outputFile = outputFile;
        if (threshold <  DefaultFileItemFactory.DEFAULT_SIZE_THRESHOLD) {
            // Small threshold, use it
            memoryOutputStream = new ByteArrayOutputStream(threshold);
        } else {
            // Large threshold. Use default and array will expand if required
            memoryOutputStream = new ByteArrayOutputStream(
                    DefaultFileItemFactory.DEFAULT_SIZE_THRESHOLD);
        }
        currentOutputStream = memoryOutputStream;
}

Constructs an instance of this class which will trigger an event at the specified threshold, and save data to a file beyond that point.

Parameters:

threshold - The number of bytes at which to trigger an event.

outputFile - The file to which data is saved beyond the threshold.

 public byte[] getData() 
{
        if (memoryOutputStream != null)
        {
            return memoryOutputStream.toByteArray();
        }
        return null;
}

Returns the data for this output stream as an array of bytes, assuming that the data has been retained in memory. If the data was written to disk, this method returns null.

 public File getFile() 
{
        return outputFile;
}

Returns the data for this output stream as a File, assuming that the data was written to disk. If the data was retained in memory, this method returns null.

 protected OutputStream getStream() throws IOException 
{
        return currentOutputStream;
}

Returns the current output stream. This may be memory based or disk based, depending on the current state with respect to the threshold.

 public boolean isInMemory() 
{
        return (!isThresholdExceeded());
}

Determines whether or not the data for this output stream has been retained in memory.

 protected  void thresholdReached() throws IOException 
{
        byte[] data = memoryOutputStream.toByteArray();
        FileOutputStream fos = new FileOutputStream(outputFile);
        fos.write(data);
        diskOutputStream = fos;
        currentOutputStream = fos;
        memoryOutputStream = null;
}

Switches the underlying output stream from a memory based stream to one that is backed by disk. This is the point at which we realise that too much data is being written to keep in memory, so we elect to switch to disk-based storage.