readlimit

Readlimit is a term that appears in the Java standard I/O framework, specifically as the parameter to the mark(int readlimit) method of an InputStream. It represents the maximum number of bytes that may be read from the stream after a mark operation while still allowing a subsequent reset to reposition back to the marked position. In practice, readlimit is a hint to the stream implementation and is not a strict guarantee.

Semantics and usage: When you call mark, the stream records its current position. A subsequent call to reset will reposition the stream to that point, provided you have not exceeded the readlimit. If more than readlimit bytes are read after the mark, the mark may be invalidated and reset can fail with an IOException. The exact behavior can vary by implementation and the stream may also invalidate the mark if the stream is closed.

Compatibility and recommendations: Not all streams support marking. You can test by calling markSupported(). If marking is not supported, mark does nothing and reset may throw an IOException. To ensure reliable mark/reset behavior, wrap the underlying stream in a class that supports marking, such as BufferedInputStream. Remember that readlimit is a practical constraint; some implementations ignore or optimize it, so the actual recoverable range may differ.

Example: Using a BufferedInputStream, you can mark a position, read up to a limit, and then reset to reread that portion if needed.

See also: mark, reset, markSupported, InputStream, BufferedInputStream.