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
    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.
    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
    Closes this piped stream and releases any system resources associated with the stream.
    void
    Causes this piped reader to be connected to the piped writer src.
    int
    Reads the next character of data from this piped stream.
    int
    read​(char[] cbuf, int off, int len)
    Reads characters into a portion of an array.
    boolean
    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 characters into a portion of an array. This method will block until some input is available, an I/O error occurs, or the end of the stream is reached.

      If len is zero, then no characters are read and 0 is returned; otherwise, there is an attempt to read at least one character. If no character is available because the stream is at its end, the value -1 is returned; otherwise, at least one character is read and stored into cbuf.

      Fewer than len characters will be read if len exceeds the pipe's buffer size.

      Specified by:
      read in class Reader
      Parameters:
      cbuf - Destination buffer
      off - Offset at which to start storing characters
      len - Maximum number of characters to read
      Returns:
      The number of characters read, or -1 if the end of the stream has been reached
      Throws:
      IndexOutOfBoundsException - If off is negative, or len is negative, or len is greater than cbuf.length - off
      IOException - if the pipe is broken, unconnected, closed, or an I/O error occurs.
    • 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.