public class

PipedInputStream

extends InputStream

java.lang.Object
↳	java.io.InputStream
	↳	java.io.PipedInputStream

Class Overview

Receives information from a communications pipe. When two threads want to pass data back and forth, one creates a piped output stream and the other one creates a piped input stream.

Summary

Constants
int	PIPE_SIZE	The size of the default pipe in bytes.

Fields
protected byte[]	buffer	The circular buffer through which data is passed.
protected int	in	The index in `buffer` where the next byte will be written.
protected int	out	The index in `buffer` where the next byte will be read.

Public Constructors
	PipedInputStream() Constructs a new unconnected `PipedInputStream`.
	PipedInputStream(PipedOutputStream out) Constructs a new `PipedInputStream` connected to the `PipedOutputStream` `out`.

Public Methods
synchronized int	available() Returns the number of bytes that are available before this stream will block.
void	close() Closes this stream.
void	connect(PipedOutputStream src) Connects this `PipedInputStream` to a `PipedOutputStream`.
synchronized int	read(byte[] bytes, int offset, int count) Reads at most `count` bytes from this stream and stores them in the byte array `bytes` starting at `offset`.
synchronized int	read() Reads a single byte from this stream and returns it as an integer in the range from 0 to 255.

Protected Methods
synchronized void	receive(int oneByte) Receives a byte and stores it in this stream's `buffer`.

[Expand]

Inherited Methods

From class java.io.InputStream

int	available() Returns the number of bytes that are available before this stream will block.
void	close() Closes this stream.
void	mark(int readlimit) Sets a mark position in this InputStream.
boolean	markSupported() Indicates whether this stream supports the `mark()` and `reset()` methods.
int	read(byte[] b, int offset, int length) Reads at most `length` bytes from this stream and stores them in the byte array `b` starting at `offset`.
int	read(byte[] b) Reads bytes from this stream and stores them in the byte array `b`.
abstract int	read() Reads a single byte from this stream and returns it as an integer in the range from 0 to 255.
synchronized void	reset() Resets this stream to the last marked location.
long	skip(long n) Skips at most `n` bytes in this stream.

From class java.lang.Object

Object	clone() Creates and returns a copy of this `Object`.
boolean	equals(Object o) Compares this instance with the specified object and indicates if they are equal.
void	finalize() Is called before the object's memory is being reclaimed by the VM.
final Class<? extends Object>	getClass() Returns the unique instance of `Class` which represents this object's class.
int	hashCode() Returns an integer hash code for this object.
final void	notify() Causes a thread which is waiting on this object's monitor (by means of calling one of the `wait()` methods) to be woken up.
final void	notifyAll() Causes all threads which are waiting on this object's monitor (by means of calling one of the `wait()` methods) to be woken up.
String	toString() Returns a string containing a concise, human-readable description of this object.
final void	wait(long millis, int nanos) Causes the calling thread to wait until another thread calls the `notify()` or `notifyAll()` method of this object or until the specified timeout expires.
final void	wait(long millis) Causes the calling thread to wait until another thread calls the `notify()` or `notifyAll()` method of this object or until the specified timeout expires.
final void	wait() Causes the calling thread to wait until another thread calls the `notify()` or `notifyAll()` method of this object.

From interface java.io.Closeable

Constants

protected static final int PIPE_SIZE

Since: API Level 1

The size of the default pipe in bytes.

Constant Value: 1024 (0x00000400)

Fields

protected byte[] buffer

Since: API Level 1

The circular buffer through which data is passed. Data is read from the range [out, in) and written to the range [in, out). Data in the buffer is either sequential:

     { - - - X X X X X X X - - - - - }
             ^             ^
             |             |
            out           in

...or wrapped around the buffer's end:

     { X X X X - - - - - - - - X X X }
               ^               ^
               |               |
              in              out

When the buffer is empty, in == -1. Reading when the buffer is empty will block until data is available. When the buffer is full, in == out. Writing when the buffer is full will block until free space is available.

protected int in

Since: API Level 1

The index in buffer where the next byte will be written.

protected int out

Since: API Level 1

The index in buffer where the next byte will be read.

Public Constructors

public PipedInputStream ()

Since: API Level 1

Constructs a new unconnected PipedInputStream. The resulting stream must be connected to a PipedOutputStream before data may be read from it.

public PipedInputStream (PipedOutputStream out)

Since: API Level 1

Constructs a new PipedInputStream connected to the PipedOutputStream out. Any data written to the output stream can be read from the this input stream.

Parameters

out	the piped output stream to connect to.

Throws

IOException	if this stream or `out` are already connected.

Public Methods

public synchronized int available ()

Since: API Level 1

Returns the number of bytes that are available before this stream will block. This implementation returns the number of bytes written to this pipe that have not been read yet.

Returns

the number of bytes available before blocking.

Throws

IOException	if an error occurs in this stream.

public void close ()

Since: API Level 1

Closes this stream. This implementation releases the buffer used for the pipe and notifies all threads waiting to read or write.

Throws

IOException	if an error occurs while closing this stream.

public void connect (PipedOutputStream src)

Since: API Level 1

Connects this PipedInputStream to a PipedOutputStream. Any data written to the output stream becomes readable in this input stream.

Parameters

src	the source output stream.

Throws

IOException	if either stream is already connected.

public synchronized int read (byte[] bytes, int offset, int count)

Since: API Level 1

Reads at most count bytes from this stream and stores them in the byte array bytes starting at offset. Blocks until at least one byte has been read, the end of the stream is detected or an exception is thrown.

Separate threads should be used to read from a PipedInputStream and to write to the connected PipedOutputStream. If the same thread is used, a deadlock may occur.

Parameters

bytes	the array in which to store the bytes read.
offset	the initial position in `bytes` to store the bytes read from this stream.
count	the maximum number of bytes to store in `bytes`.

Returns

the number of bytes actually read or -1 if the end of the stream has been reached.

Throws

IndexOutOfBoundsException	if `offset < 0` or `count < 0`, or if `offset + count` is greater than the size of `bytes`.
InterruptedIOException	if the thread reading from this stream is interrupted.
IOException	if this stream is closed or not connected to an output stream, or if the thread writing to the connected output stream is no longer alive.
NullPointerException	if `bytes` is `null`.

public synchronized int read ()

Since: API Level 1

Reads a single byte from this stream and returns it as an integer in the range from 0 to 255. Returns -1 if the end of this stream has been reached. If there is no data in the pipe, this method blocks until data is available, the end of the stream is detected or an exception is thrown.

Separate threads should be used to read from a PipedInputStream and to write to the connected PipedOutputStream. If the same thread is used, a deadlock may occur.

Returns

the byte read or -1 if the end of the source stream has been reached.

Throws

IOException	if this stream is closed or not connected to an output stream, or if the thread writing to the connected output stream is no longer alive.

Protected Methods

protected synchronized void receive (int oneByte)

Since: API Level 1

Receives a byte and stores it in this stream's buffer. This method is called by write(int). The least significant byte of the integer oneByte is stored at index in in the buffer.

This method blocks as long as buffer is full.

Parameters

oneByte	the byte to store in this pipe.

Throws

InterruptedIOException	if the `buffer` is full and the thread that has called this method is interrupted.
IOException	if this stream is closed or the thread that has last read from this stream is no longer alive.

Interfaces

Classes

Exceptions

PipedInputStream

Class Overview

See Also

Summary

Constants

protected static final int PIPE_SIZE

Fields

protected byte[] buffer

protected int in

protected int out

Public Constructors

public PipedInputStream ()

public PipedInputStream (PipedOutputStream out)

Parameters

Throws

Public Methods

public synchronized int available ()

Returns

Throws

public void close ()

Throws

public void connect (PipedOutputStream src)

Parameters

Throws

public synchronized int read (byte[] bytes, int offset, int count)

Parameters

Returns

Throws

public synchronized int read ()

Returns

Throws

Protected Methods

protected synchronized void receive (int oneByte)

Parameters

Throws