Module java.base
Package java.io

Class PipedReader

java.lang.Object
java.io.Reader
java.io.PipedReader
All Implemented Interfaces:
Closeable, AutoCloseable, Readable
public class PipedReader
extends Reader
Piped character-input streams.
Since:
1.1

  • Field Summary

    Fields declared in class java.io.Reader

    lock

  • Constructor Summary

    Constructors 
    Constructor Description
    PipedReader()
    Creates a PipedReader so that it is not yet connected.
    PipedReader​(int pipeSize)
    Creates a PipedReader so that it is not yet connected and uses the specified pipe size for the pipe's buffer.
    PipedReader​(PipedWriter src)
    Creates a PipedReader so that it is connected to the piped writer src.
    PipedReader​(PipedWriter src, int pipeSize)
    Creates a PipedReader so that it is connected to the piped writer src and uses the specified pipe size for the pipe's buffer.

  • Method Summary

    Modifier and Type Method Description
    void close()
    Closes this piped stream and releases any system resources associated with the stream.
    void connect​(PipedWriter src)
    Causes this piped reader to be connected to the piped writer src.
    int read()
    Reads the next character of data from this piped stream.
    int read​(char[] cbuf, int off, int len)
    Reads up to len characters of data from this piped stream into an array of characters.
    boolean ready()
    Tell whether this stream is ready to be read.

    Methods declared in class java.io.Reader

    mark, markSupported, nullReader, read, read, reset, skip, transferTo

    Methods declared in class java.lang.Object

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

  • Constructor Details

    • PipedReader

      public PipedReader​(PipedWriter src) throws IOException
      Creates a PipedReader so that it is connected to the piped writer src. Data 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.

    • PipedReader

      public PipedReader​(PipedWriter src, int pipeSize) throws IOException
      Creates a PipedReader so that it is connected to the piped writer src and uses the specified pipe size for the pipe's buffer. Data 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

    • PipedReader

      public PipedReader()
      Creates a PipedReader so that it is not yet connected. It must be connected to a PipedWriter before being used.

    • PipedReader

      public PipedReader​(int pipeSize)
      Creates a PipedReader so that it is not yet connected and uses the specified pipe size for the pipe's buffer. It must be connected to a PipedWriter before being used.
      Parameters:
      pipeSize - the size of the pipe's buffer.
      Throws:
      IllegalArgumentException - if pipeSize <= 0.
      Since:
      1.6

  • Method Details

    • connect

      public void connect​(PipedWriter src) throws IOException
      Causes this piped reader to be connected to the piped writer src. If this object is already connected to some other piped writer, an IOException is thrown.

      If src is an unconnected piped writer and snk is an unconnected piped reader, 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 writer to connect to.
      Throws:
      IOException - if an I/O error occurs.

    • read

      public int read() throws IOException
      Reads the next character of data from this piped stream. If no character is available because the end of the stream has been reached, the value -1 is returned. This method blocks until input data is available, the end of the stream is detected, or an exception is thrown.
      Overrides:
      read in class Reader
      Returns:
      the next character of data, or -1 if the end of the stream is reached.
      Throws:
      IOException - if the pipe is broken, unconnected, closed, or an I/O error occurs.

    • read

      public int read​(char[] cbuf, int off, int len) throws IOException
      Reads up to len characters of data from this piped stream into an array of characters. Less than len characters will be read if the end of the data stream is reached or if len exceeds the pipe's buffer size. This method blocks until at least one character of input is available.
      Specified by:
      read in class Reader
      Parameters:
      cbuf - the buffer into which the data is read.
      off - the start offset of the data.
      len - the maximum number of characters read.
      Returns:
      the total number of characters read into the buffer, or -1 if there is no more data because the end of the stream has been reached.
      Throws:
      IOException - if the pipe is broken, unconnected, closed, or an I/O error occurs.
      IndexOutOfBoundsException - If off is negative, or len is negative, or len is greater than cbuf.length - off

    • ready

      public boolean ready() throws IOException
      Tell whether this stream is ready to be read. A piped character stream is ready if the circular buffer is not empty.
      Overrides:
      ready in class Reader
      Returns:
      True if the next read() is guaranteed not to block for input, false otherwise. Note that returning false does not guarantee that the next read will block.
      Throws:
      IOException - if the pipe is broken, unconnected, or closed.

    • close

      public void close() throws IOException
      Closes this piped stream and releases any system resources associated with the stream.
      Specified by:
      close in interface AutoCloseable
      Specified by:
      close in interface Closeable
      Specified by:
      close in class Reader
      Throws:
      IOException - if an I/O error occurs.