PipedInputStream

The size of the default pipe in bytes.

The circular buffer through which data is passed. Data is read from the range [out, in) and written to the range [in, out). Data in the buffer is either sequential:

     { - - - X X X X X X X - - - - - }
             ^             ^
             |             |
            out           in

     { X X X X - - - - - - - - X X X }
               ^               ^
               |               |
              in              out

The index in buffer where the next byte will be written.

The index in buffer where the next byte will be read.

Constructs a new unconnected PipedInputStream. The resulting stream must be connected to a PipedOutputStream before data may be read from it.

Constructs a new PipedInputStream connected to the PipedOutputStream out. Any data written to the output stream can be read from the this input stream.

Returns an estimated number of bytes that can be read or skipped without blocking for more input.

Note that this method provides such a weak guarantee that it is not very useful in practice.

Firstly, the guarantee is "without blocking for more input" rather than "without blocking": a read may still block waiting for I/O to complete — the guarantee is merely that it won't have to wait indefinitely for data to be written. The result of this method should not be used as a license to do I/O on a thread that shouldn't be blocked.

Secondly, the result is a conservative estimate and may be significantly smaller than the actual number of bytes available. In particular, an implementation that always returns 0 would be correct. In general, callers should only use this method if they'd be satisfied with treating the result as a boolean yes or no answer to the question "is there definitely data ready?".

Thirdly, the fact that a given number of bytes is "available" does not guarantee that a read or skip will actually read or skip that many bytes: they may read or skip fewer.

It is particularly important to realize that you must not use this method to size a container and assume that you can read the entirety of the stream without needing to resize the container. Such callers should probably write everything they read to a ByteArrayOutputStream and convert that to a byte array. Alternatively, if you're reading from a file, length() returns the current length of the file (though assuming the file's length can't change may be incorrect, reading a file is inherently racy).

The default implementation of this method in InputStream always returns 0. Subclasses should override this method if they are able to indicate the number of bytes available.

Unlike most streams, PipedInputStream returns 0 rather than throwing IOException if the stream has been closed. Unconnected and broken pipes also return 0.

Closes this stream. This implementation releases the buffer used for the pipe and notifies all threads waiting to read or write.

Connects this PipedInputStream to a PipedOutputStream. Any data written to the output stream becomes readable in this input stream.

Reads at most count bytes from this stream and stores them in the byte array bytes starting at offset. Blocks until at least one byte has been read, the end of the stream is detected or an exception is thrown.

Separate threads should be used to read from a PipedInputStream and to write to the connected PipedOutputStream. If the same thread is used, a deadlock may occur.

Reads a single byte from this stream and returns it as an integer in the range from 0 to 255. Returns -1 if the end of this stream has been reached. If there is no data in the pipe, this method blocks until data is available, the end of the stream is detected or an exception is thrown.

Separate threads should be used to read from a PipedInputStream and to write to the connected PipedOutputStream. If the same thread is used, a deadlock may occur.

Receives a byte and stores it in this stream's buffer. This method is called by write(int). The least significant byte of the integer oneByte is stored at index in in the buffer.

This method blocks as long as buffer is full.