Class LookaheadInputStream

All Implemented Interfaces:
Closeable, AutoCloseable

public class LookaheadInputStream extends InputStream
Stream wrapper that make it easy to read up to n bytes ahead from a stream that supports the mark feature. This class insulates the underlying stream from things like possible mark(), reset() and close() calls by external components that might otherwise invalidate the marked state of a stream.

The recommended usage pattern of this class is:

     try (InputStream lookahead = new LookaheadInputStream(stream, n)) {

This usage pattern guarantees that only up to n bytes from the original stream can ever be read, and that the stream will have been marked and then reset to its original state once the above code block exits. No code in the fictional processStream() method can affect the the state of the original stream.

Apache Tika 0.10
  • Constructor Details

    • LookaheadInputStream

      public LookaheadInputStream(InputStream stream, int n)
      Creates a lookahead wrapper for the given input stream. The given input stream should support the mark feature, as otherwise the state of that stream will be undefined after the lookahead wrapper has been closed. As a special case a null stream is treated as an empty stream.
      stream - input stream, can be null
      n - maximum number of bytes to look ahead
  • Method Details