java.lang.Object | ||
↳ | java.io.InputStream | |
↳ | java.io.PipedInputStream |
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.
Constants | |||||||||||
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int | PIPE_SIZE | The size of the default pipe in bytes. |
Fields | |||||||||||
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buffer | The circular buffer through which data is passed. | ||||||||||
in | The index in buffer where the next byte will be written. |
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out | The index in buffer where the next byte will be read. |
Public Constructors | |||||||||||
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Constructs a new unconnected
PipedInputStream . | |||||||||||
Constructs a new unconnected
PipedInputStream with the given
buffer size. | |||||||||||
Constructs a new
PipedInputStream connected to the given PipedOutputStream ,
with the given buffer size. |
Public Methods | |||||||||||
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Returns an estimated number of bytes that can be read or skipped without blocking for more
input.
Unlike most streams, | |||||||||||
Closes this stream.
| |||||||||||
Connects this
PipedInputStream to a PipedOutputStream . | |||||||||||
Reads a single byte from this stream and returns it as an integer in the
range from 0 to 255.
| |||||||||||
Reads up to
byteCount bytes from this stream and stores them in the
byte array bytes starting at byteOffset . |
Protected Methods | |||||||||||
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Receives a byte and stores it in this stream's
buffer . |
[Expand]
Inherited Methods | |||||||||||
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From class
java.io.InputStream
| |||||||||||
From class
java.lang.Object
| |||||||||||
From interface
java.io.Closeable
| |||||||||||
From interface
java.lang.AutoCloseable
|
The size of the default pipe in bytes.
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 outWhen 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.
Constructs a new unconnected PipedInputStream
. The resulting
stream must be connected to a PipedOutputStream
before data may
be read from it.
Constructs a new PipedInputStream
connected to the
PipedOutputStream
out
. Any data written to the output
stream can be read from the this input stream.
out | the piped output stream to connect to. |
---|
IOException | if this stream or out are already connected.
|
---|
Constructs a new unconnected PipedInputStream
with the given
buffer size. The resulting stream must be connected to a
PipedOutputStream
before data may be read from it.
pipeSize | the size of the buffer in bytes. |
---|
IllegalArgumentException | if pipeSize is less than or equal to zero. |
---|
Constructs a new PipedInputStream
connected to the given PipedOutputStream
,
with the given buffer size. Any data written to the output stream can be read from this
input stream.
out | the PipedOutputStream to connect to. |
---|---|
pipeSize | the size of the buffer in bytes. |
IOException | if an I/O error occurs. |
---|---|
IllegalArgumentException | if pipeSize is less than or equal to zero. |
Returns an estimated number of bytes that can be read or skipped without blocking for more input.
Note that this method provides such a weak guarantee that it is not very useful in practice.
Firstly, the guarantee is "without blocking for more input" rather than "without blocking": a read may still block waiting for I/O to complete — the guarantee is merely that it won't have to wait indefinitely for data to be written. The result of this method should not be used as a license to do I/O on a thread that shouldn't be blocked.
Secondly, the result is a conservative estimate and may be significantly smaller than the actual number of bytes available. In particular, an implementation that always returns 0 would be correct. In general, callers should only use this method if they'd be satisfied with treating the result as a boolean yes or no answer to the question "is there definitely data ready?".
Thirdly, the fact that a given number of bytes is "available" does not guarantee that a read or skip will actually read or skip that many bytes: they may read or skip fewer.
It is particularly important to realize that you must not use this method to
size a container and assume that you can read the entirety of the stream without needing
to resize the container. Such callers should probably write everything they read to a
ByteArrayOutputStream
and convert that to a byte array. Alternatively, if you're
reading from a file, length()
returns the current length of the file (though
assuming the file's length can't change may be incorrect, reading a file is inherently
racy).
The default implementation of this method in InputStream
always returns 0.
Subclasses should override this method if they are able to indicate the number of bytes
available.
Unlike most streams, PipedInputStream
returns 0 rather than throwing
IOException
if the stream has been closed. Unconnected and broken pipes also
return 0.
IOException | if an I/O error occurs |
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Closes this stream. This implementation releases the buffer used for the pipe and notifies all threads waiting to read or write.
IOException | if an error occurs while closing this stream. |
---|
Connects this PipedInputStream
to a PipedOutputStream
.
Any data written to the output stream becomes readable in this input
stream.
src | the source output stream. |
---|
IOException | if either stream is already connected. |
---|
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.
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. |
---|
Reads up to byteCount
bytes from this stream and stores them in the
byte array bytes
starting at byteOffset
. 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.
Returns the number of bytes actually read or -1 if the end of the stream has been reached.
IndexOutOfBoundsException | if byteOffset < 0 || byteCount < 0 || byteOffset + byteCount > bytes.length . |
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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 .
|
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.
oneByte | the byte to store in this pipe. |
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InterruptedIOException | if the buffer is full and the thread that has called
this method is interrupted. |
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IOException | if this stream is closed or the thread that has last read from this stream is no longer alive. |