public
class
PipedInputStream
extends InputStream
java.lang.Object | ||
↳ | java.io.InputStream | |
↳ | java.io.PipedInputStream |
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 a PipedInputStream
object by one thread and data is written
to the corresponding PipedOutputStream
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 be broken if a
thread that was providing data bytes to the connected
piped output stream is no longer alive.
See also:
Constants | |
---|---|
int |
PIPE_SIZE
The default size of the pipe's circular input buffer. |
Fields | |
---|---|
protected
byte[] |
buffer
The circular buffer into which incoming data is placed. |
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. |
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. |
Public constructors | |
---|---|
PipedInputStream(PipedOutputStream src)
Creates a |
|
PipedInputStream(PipedOutputStream src, int pipeSize)
Creates a |
|
PipedInputStream()
Creates a |
|
PipedInputStream(int pipeSize)
Creates a |
Public methods | |
---|---|
int
|
available()
Returns the number of bytes that can be read from this input stream without blocking. |
void
|
close()
Closes this piped input stream and releases any system resources associated with the stream. |
void
|
connect(PipedOutputStream src)
Causes this piped input stream to be connected
to the piped output stream |
int
|
read()
Reads the next byte of data from this piped input stream. |
int
|
read(byte[] b, int off, int len)
Reads up to |
Protected methods | |
---|---|
void
|
receive(int b)
Receives a byte of data. |
Inherited methods | |
---|---|
From
class
java.io.InputStream
| |
From
class
java.lang.Object
| |
From
interface
java.io.Closeable
| |
From
interface
java.lang.AutoCloseable
|
int PIPE_SIZE
The default size of the pipe's circular input buffer.
Constant Value: 1024 (0x00000400)
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
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.
PipedInputStream (PipedOutputStream src)
Creates a PipedInputStream
so
that it is connected to the piped output
stream src
. Data bytes written
to src
will then be available
as input from this stream.
Parameters | |
---|---|
src |
PipedOutputStream :
the stream to connect to. |
Throws | |
---|---|
IOException |
if an I/O error occurs. |
PipedInputStream (PipedOutputStream src, int pipeSize)
Creates a PipedInputStream
so that it is
connected to the piped output stream
src
and uses the specified pipe size for
the pipe's buffer.
Data bytes written to src
will then
be available as input from this stream.
Parameters | |
---|---|
src |
PipedOutputStream :
the stream to connect to. |
pipeSize |
int :
the size of the pipe's buffer. |
Throws | |
---|---|
IOException |
if an I/O error occurs. |
IllegalArgumentException |
if pipeSize <= 0 . |
PipedInputStream ()
Creates a PipedInputStream
so
that it is not yet connected.
It must be connected to a
PipedOutputStream
before being used.
PipedInputStream (int pipeSize)
Creates a PipedInputStream
so that it is not yet
connected and
uses the specified pipe size for the pipe's buffer.
It must be connected to a PipedOutputStream
before being used.
Parameters | |
---|---|
pipeSize |
int :
the size of the pipe's buffer. |
Throws | |
---|---|
IllegalArgumentException |
if pipeSize <= 0 . |
int available ()
Returns the number of bytes that can be read from this input stream without blocking.
Returns | |
---|---|
int |
the number of bytes that can be read from this input stream
without blocking, or 0 if this input stream has been
closed by invoking its close() method, or if the pipe
is unconnected , or
broken . |
Throws | |
---|---|
IOException |
if an I/O error occurs. |
void close ()
Closes this piped input stream and releases any system resources associated with the stream.
Throws | |
---|---|
IOException |
if an I/O error occurs. |
void connect (PipedOutputStream src)
Causes this piped input stream to be connected
to the piped output stream src
.
If this object is already connected to some
other piped output stream, an IOException
is thrown.
If src
is an
unconnected piped output stream and snk
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 |
PipedOutputStream :
The piped output stream to connect to. |
Throws | |
---|---|
IOException |
if an I/O error occurs. |
int read ()
Reads the next byte of data from this piped input stream. The
value byte is returned as an int
in the range
0
to 255
.
This method blocks until input data is available, the end of the
stream is detected, or an exception is thrown.
Returns | |
---|---|
int |
the next byte of data, or -1 if the end of the
stream is reached. |
Throws | |
---|---|
IOException |
if the pipe is
unconnected ,
broken , closed,
or if an I/O error occurs.
|
int read (byte[] b, int off, int len)
Reads up to len
bytes of data from this piped input
stream into an array of bytes. Less than len
bytes
will be read if the end of the data stream is reached or if
len
exceeds the pipe's buffer size.
If len
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.
Parameters | |
---|---|
b |
byte :
the buffer into which the data is read. |
off |
int :
the start offset in the destination array b |
len |
int :
the maximum number of bytes read. |
Returns | |
---|---|
int |
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 |
If b is null . |
IndexOutOfBoundsException |
If off is negative,
len is negative, or len is greater than
b.length - off |
IOException |
if the pipe is broken ,
unconnected ,
closed, or if an I/O error occurs.
|
void receive (int b)
Receives a byte of data. This method will block if no input is available.
Parameters | |
---|---|
b |
int :
the byte being received |
Throws | |
---|---|
IOException |
If the pipe is broken ,
unconnected ,
closed, or if an I/O error occurs. |