All Implemented Interfaces:

Closeable, AutoCloseable

public class PipedInputStream
extends InputStream

A piped input stream should be connected to a piped output stream; the piped input stream then provides whatever data bytes are written to the piped output stream. Typically, data is read from a PipedInputStream object by one thread and data is written to the corresponding PipedOutputStream by some other thread. Attempting to use both objects from a single thread is not recommended, as it may deadlock the thread. The piped input stream contains a buffer, decoupling read operations from write operations, within limits. A pipe is said to be broken if a thread that was providing data bytes to the connected piped output stream is no longer alive.

Since:

1.0

See Also:

PipedOutputStream

• Field Summary

  Fields 

  Modifier and Type	Field	Description
  protected byte[]	buffer	The circular buffer into which incoming data is placed.
  protected int	in	The index of the position in the circular buffer at which the next byte of data will be stored when received from the connected piped output stream.
  protected int	out	The index of the position in the circular buffer at which the next byte of data will be read by this piped input stream.
  protected static int	PIPE_SIZE	The default size of the pipe's circular input buffer.

• Constructor Summary

  Constructors 

  Constructor	Description
  PipedInputStream()	Creates a PipedInputStream so that it is not yet connected.
  PipedInputStream​(int pipeSize)	Creates a PipedInputStream so that it is not yet connected and uses the specified pipe size for the pipe's buffer.
  PipedInputStream​(PipedOutputStream src)	Creates a PipedInputStream so that it is connected to the piped output stream src.
  PipedInputStream​(PipedOutputStream src, int pipeSize)	Creates a PipedInputStream so that it is connected to the piped output stream src and uses the specified pipe size for the pipe's buffer.

• Method Summary

  Modifier and Type	Method	Description
  int	available()	Returns the number of bytes that can be read from this input stream without blocking.
  void	close()	Closes this piped input stream and releases any system resources associated with the stream.
  void	connect​(PipedOutputStream src)	Causes this piped input stream to be connected to the piped output stream src.
  int	read()	Reads the next byte of data from this piped input stream.
  int	read​(byte[] b, int off, int len)	Reads up to len bytes of data from this piped input stream into an array of bytes.
  protected void	receive​(int b)	Receives a byte of data.

  Methods declared in class java.io.InputStream

  mark, markSupported, nullInputStream, read, readAllBytes, readNBytes, readNBytes, reset, skip, skipNBytes, transferTo

  Methods declared in class java.lang.Object

  clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

• Field Details

  • PIPE_SIZE

    protected static final int PIPE_SIZE

    The default size of the pipe's circular input buffer.

    Since:

    1.1

    See Also:

    Constant Field Values

  • buffer

    protected byte[] buffer

    The circular buffer into which incoming data is placed.

    Since:

    1.1

  • in

    protected int in

    The index of the position in the circular buffer at which the next byte of data will be stored when received from the connected piped output stream. in<0 implies the buffer is empty, in==out implies the buffer is full

    Since:

    1.1

  • out

    protected int out

    The index of the position in the circular buffer at which the next byte of data will be read by this piped input stream.

    Since:

    1.1

• Constructor Details

  • PipedInputStream

    Creates a PipedInputStream so that it is connected to the piped output stream src. Data bytes written to src will then be available as input from this stream.

    Parameters:

    src - the stream to connect to.

    Throws:

    IOException - if an I/O error occurs.

  • PipedInputStream

    Creates a PipedInputStream so that it is connected to the piped output stream src and uses the specified pipe size for the pipe's buffer. Data bytes written to src will then be available as input from this stream.

    Parameters:

    src - the stream to connect to.

    pipeSize - the size of the pipe's buffer.

    Throws:

    IOException - if an I/O error occurs.

    IllegalArgumentException - if pipeSize <= 0.

    Since:

    1.6

  • PipedInputStream

    public PipedInputStream()

    Creates a PipedInputStream so that it is not yet connected. It must be connected to a PipedOutputStream before being used.

  • PipedInputStream

    public PipedInputStream​(int pipeSize)

    Creates a PipedInputStream so that it is not yet connected and uses the specified pipe size for the pipe's buffer. It must be connected to a PipedOutputStream before being used.

    Parameters:

    pipeSize - the size of the pipe's buffer.

    Throws:

    IllegalArgumentException - if pipeSize <= 0.

    Since:

    1.6

• Method Details

  • connect

    Causes this piped input stream to be connected to the piped output stream src. If this object is already connected to some other piped output stream, an IOException is thrown.

    If src is an unconnected piped output stream and snk is an unconnected piped input stream, they may be connected by either the call:

    snk.connect(src) 

    or the call:

    src.connect(snk) 

    The two calls have the same effect.

    Parameters:

    src - The piped output stream to connect to.

    Throws:

    IOException - if an I/O error occurs.

  • receive

    protected void receive​(int b) throws IOException

    Receives a byte of data. This method will block if no input is available.

    Parameters:

    b - the byte being received

    Throws:

    IOException - If the pipe is broken, unconnected, closed, or if an I/O error occurs.

    Since:

    1.1

  • read

    Reads the next byte of data from this piped input stream. The value byte is returned as an int in the range 0 to 255. This method blocks until input data is available, the end of the stream is detected, or an exception is thrown.

    Specified by:

    read in class InputStream

    Returns:

    the next byte of data, or -1 if the end of the stream is reached.

    Throws:

    IOException - if the pipe is unconnected, broken, closed, or if an I/O error occurs.

  • read

    public int read​(byte[] b, int off, int len) throws IOException

    Reads up to len bytes of data from this piped input stream into an array of bytes. Less than len bytes will be read if the end of the data stream is reached or if len exceeds the pipe's buffer size. If len is zero, then no bytes are read and 0 is returned; otherwise, the method blocks until at least 1 byte of input is available, end of the stream has been detected, or an exception is thrown.

    Overrides:

    read in class InputStream

    Parameters:

    b - the buffer into which the data is read.

    off - the start offset in the destination array b

    len - the maximum number of bytes read.

    Returns:

    the total number of bytes read into the buffer, or -1 if there is no more data because the end of the stream has been reached.

    Throws:

    NullPointerException - If b is null.

    IndexOutOfBoundsException - If off is negative, len is negative, or len is greater than b.length - off

    IOException - if the pipe is broken, unconnected, closed, or if an I/O error occurs.

    See Also:

    InputStream.read()

  • available

    Returns the number of bytes that can be read from this input stream without blocking.

    Overrides:

    available in class InputStream

    Returns:

    the number of bytes that can be read from this input stream without blocking, or 0 if this input stream has been closed by invoking its close() method, or if the pipe is unconnected, or broken.

    Throws:

    IOException - if an I/O error occurs.

    Since:

    1.0.2

  • close

    Closes this piped input stream and releases any system resources associated with the stream.

    Specified by:

    close in interface AutoCloseable

    Specified by:

    close in interface Closeable

    Overrides:

    close in class InputStream

    Throws:

    IOException - if an I/O error occurs.