Module java.base
Package java.io

Class PipedInputStream

  • All Implemented Interfaces:
    Closeable,AutoCloseable

    public classPipedInputStreamextendsInputStream
    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 aPipedInputStream object by one thread and data is written to the correspondingPipedOutputStream 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 bebroken 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 TypeFieldDescription
      protected byte[]buffer
      The circular buffer into which incoming data is placed.
      protected intin
      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 intout
      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 intPIPE_SIZE
      The default size of the pipe's circular input buffer.
    • Constructor Summary

      Constructors 
      ConstructorDescription
      PipedInputStream()
      Creates aPipedInputStream so that it is not yetconnected.
      PipedInputStream​(int pipeSize)
      Creates aPipedInputStream so that it is not yetconnected and uses the specified pipe size for the pipe's buffer.
      PipedInputStream​(PipedOutputStream src)
      Creates aPipedInputStream so that it is connected to the piped output streamsrc.
      PipedInputStream​(PipedOutputStream src, int pipeSize)
      Creates aPipedInputStream so that it is connected to the piped output streamsrc and uses the specified pipe size for the pipe's buffer.
    • Field Detail

      • 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 Detail

      • PipedInputStream

        public PipedInputStream​(PipedOutputStream src)                 throwsIOException
        Creates aPipedInputStream so that it is connected to the piped output streamsrc. Data bytes written tosrc 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

        public PipedInputStream​(PipedOutputStream src,                        int pipeSize)                 throwsIOException
        Creates aPipedInputStream so that it is connected to the piped output streamsrc and uses the specified pipe size for the pipe's buffer. Data bytes written tosrc 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 - ifpipeSize <= 0.
        Since:
        1.6
      • PipedInputStream

        public PipedInputStream()
        Creates aPipedInputStream so that it is not yetconnected. It must beconnected to aPipedOutputStream before being used.
      • PipedInputStream

        public PipedInputStream​(int pipeSize)
        Creates aPipedInputStream so that it is not yetconnected and uses the specified pipe size for the pipe's buffer. It must beconnected to aPipedOutputStream before being used.
        Parameters:
        pipeSize - the size of the pipe's buffer.
        Throws:
        IllegalArgumentException - ifpipeSize <= 0.
        Since:
        1.6
    • Method Detail

      • connect

        public void connect​(PipedOutputStream src)             throwsIOException
        Causes this piped input stream to be connected to the piped output streamsrc. If this object is already connected to some other piped output stream, anIOException is thrown.

        Ifsrc is an unconnected piped output stream andsnk 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)                throwsIOException
        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 isbroken,unconnected, closed, or if an I/O error occurs.
        Since:
        1.1
      • read

        public int read()         throwsIOException
        Reads the next byte of data from this piped input stream. The value byte is returned as anint in the range0 to255. 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 isunconnected,broken, closed, or if an I/O error occurs.
      • read

        public int read​(byte[] b,                int off,                int len)         throwsIOException
        Reads up tolen bytes of data from this piped input stream into an array of bytes. Less thanlen bytes will be read if the end of the data stream is reached or iflen exceeds the pipe's buffer size. Iflen 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 arrayb
        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 - Ifb isnull.
        IndexOutOfBoundsException - Ifoff is negative,len is negative, orlen is greater thanb.length - off
        IOException - if the pipe isbroken,unconnected, closed, or if an I/O error occurs.
        See Also:
        InputStream.read()
      • available

        public int available()              throwsIOException
        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, or0 if this input stream has been closed by invoking itsclose() method, or if the pipe isunconnected, orbroken.
        Throws:
        IOException - if an I/O error occurs.
        Since:
        1.0.2