Java(TM) 2 Platform, Standard Edition, v1.2.2 API Specification: Class PipedInputStream - JDK 5 Documentation v1.2.2, Java 2 SDK 英文文档

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java.io
Class PipedInputStream

java.lang.Object
  |
  +--java.io.InputStream
        |
        +--java.io.PipedInputStream

public class PipedInputStream
extends InputStream

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.

Since:: JDK1.0
See Also:: PipedOutputStream

Field Summary

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.

protected static int PIPE_SIZE
          The size of the pipe's circular input buffer.

Constructor Summary

PipedInputStream()
          Creates a PipedInputStream so that it is not yet connected.

PipedInputStream(PipedOutputStream src)
          Creates a PipedInputStream so that it is connected to the piped output stream src.

Method Summary

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 src.

int read()
          Reads the next byte of data from this piped input stream.

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.

protected void receive(int b)
          Receives a byte of data.

Methods inherited from class java.io.InputStream

mark, markSupported, read, reset, skip

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

PIPE_SIZE

protected static final int PIPE_SIZE

The size of the pipe's circular input buffer.

Since:: JDK1.1

buffer

protected byte[] buffer

The circular buffer into which incoming data is placed.

Since:: JDK1.1

in

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. in<0 implies the buffer is empty, in==out implies the buffer is full

Since:: JDK1.1

out

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.

Since:: JDK1.1

Constructor Detail

PipedInputStream

public PipedInputStream(PipedOutputStream src)
                 throws IOException

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 - the stream to connect to.
Throws:: IOException - if an I/O error occurs.

PipedInputStream

public PipedInputStream()

Creates a PipedInputStream so that it is not yet connected. It must be connected to a PipedOutputStream before being used.

See Also:: connect(java.io.PipedOutputStream), PipedOutputStream.connect(java.io.PipedInputStream)

Method Detail

connect

public void connect(PipedOutputStream src)
             throws IOException

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 - The piped output stream to connect to.
Throws:: IOException - if an I/O error occurs.

receive

protected void receive(int b)
                throws IOException

Receives a byte of data. This method will block if no input is available.

Parameters:: b - the byte being received
Throws:: IOException - If the pipe is broken.
Since:: JDK1.1

read

public int read()
         throws IOException

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. If no byte 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 bytes to the connected piped output stream, but the thread is no longer alive, then an IOException is thrown.

Overrides:: read in class InputStream

Returns:: the next byte of data, or -1 if the end of the stream is reached.
Throws:: IOException - if the pipe is broken.

read

public int read(byte[] b,
                int off,
                int len)
         throws IOException

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

Overrides:: read in class InputStream

Parameters:: b - the buffer into which the data is read.; off - the start offset of the data.; len - the maximum number of bytes read.
Returns:: 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:: IOException - if an I/O error occurs.

available

public int available()
              throws IOException

Returns the number of bytes that can be read from this input stream without blocking. This method overrides the available method of the parent class.

Overrides:: available in class InputStream

Returns:: the number of bytes that can be read from this input stream without blocking.
Throws:: IOException - if an I/O error occurs.
Since:: JDK1.0.2

close

public void close()
           throws IOException

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

Overrides:: close in class InputStream

Throws:: IOException - if an I/O error occurs.

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Field Summary
`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.
`protected static int`	`PIPE_SIZE` The size of the pipe's circular input buffer.

Constructor Summary
`PipedInputStream()` Creates a `PipedInputStream` so that it is not yet connected.
`PipedInputStream(PipedOutputStream src)` Creates a `PipedInputStream` so that it is connected to the piped output stream `src`.

Method Summary
`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 `src`.
`int`	`read()` Reads the next byte of data from this piped input stream.
`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.
`protected void`	`receive(int b)` Receives a byte of data.

Java(TM) 2 Platform, Standard Edition, v1.2.2 API Specification: Class PipedInputStream - JDK 5 Documentation v1.2.2, Java 2 SDK 英文文档

java.io Class PipedInputStream

PIPE_SIZE

buffer

in

out

PipedInputStream

PipedInputStream

connect

receive

read

read

available

close

java.io
Class PipedInputStream