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## java.io
Class PipedReader

    java.lang.Object
      java.io.Reader
          java.io.PipedReader

All Implemented Interfaces:
  Closeable, Readable

    public class PipedReader

extends Reader

Piped character-input streams.

Since:
  JDK1.1

Field Summary

Fields inherited from class java.io.Reader
`lock`

Constructor Summary
`PipedReader()` Creates a `PipedReader` so that it is not yet connected.
`PipedReader(PipedWriter src)` Creates a `PipedReader` so that it is connected to the piped writer `src`.

Method Summary
`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 inherited from class java.io.Reader
`mark, markSupported, read, read, reset, skip`

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Constructor Detail

### 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()

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

  See Also:
    `connect(java.io.PipedWriter)`, `PipedWriter.connect(java.io.PipedReader)`

Method Detail

### 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. If a thread was providing data characters to the connected piped writer, but the thread is no longer alive, then an `IOException` 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.

### 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. This method blocks until at least one character of input is available. If a thread was providing data characters to the connected piped output, but the thread is no longer alive, then an `IOException` is thrown.

  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 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 an I/O error occurs

### close

    public void close()
               throws IOException

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

  Specified by:
    `close` in interface `Closeable`
  Specified by:
    `close` in class `Reader`
  Throws:
    `IOException` - if an I/O error occurs.

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For further API reference and developer documentation, see Java 2 SDK SE Developer Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.

Copyright 2004 Sun Microsystems, Inc. All rights reserved. Use is subject to license terms. Also see the documentation redistribution policy.