Class DeferredFileOutputStream

All Implemented Interfaces:
Closeable, Flushable, AutoCloseable

public class DeferredFileOutputStream extends ThresholdingOutputStream
An output stream which will retain data in memory until a specified threshold is reached, and only then commit it to disk. If the stream is closed before the threshold is reached, the data will not be written to disk at all.

This class originated in FileUpload processing. In this use case, you do not know in advance the size of the file being uploaded. If the file is small you want to store it in memory (for speed), but if the file is large you want to store it to file (to avoid memory issues).