Package cmion.util

Class WrappedOutputStream

java.lang.Object

java.io.OutputStream

java.io.FilterOutputStream

cmion.util.WrappedOutputStream

All Implemented Interfaces:

java.io.Closeable, java.io.Flushable, java.lang.AutoCloseable

public class WrappedOutputStream
extends java.io.FilterOutputStream

This output stream works in conjunction with the WrappedInputStream to introduce a protocol for sending arbitrary length data in a uniform way. This output stream allows variable length data to be inserted into an existing output stream so that it can be read by an input stream without reading too many bytes (in case of buffering by the input stream).

This output stream is used like any normal output stream. The protocol is introduced by the WrappedOutputStream and does not need to be known by the user of this class. However, for those that are interested, the method is described below.

The output stream writes the requested bytes as packets of binary information. The packet consists of a header and payload. The header is two bytes of a single unsigned short (written in network order) that specifies the length of bytes in the payload. A header value of 0 indicates that the stream is "closed".

Note: For this wrapped output stream to be used, the application must call close() to end the output.

Version:

$Id: WrappedOutputStream.java 447688 2006-09-19 02:39:49Z mrglavas $

Author:

Andy Clark, IBM

See Also:

WrappedInputStream

Field Summary

Fields

Modifier and Type	Field	Description
static int	DEFAULT_BUFFER_SIZE	Default buffer size (1024).
protected byte[]	fBuffer	Buffer.
protected java.io.DataOutputStream	fDataOutputStream	Data output stream.
protected int	fPosition	Buffer position.

Fields inherited from class java.io.FilterOutputStream

out

Constructor Summary

Constructors

Constructor	Description
WrappedOutputStream(java.io.OutputStream stream)	Constructs a wrapper for the given output stream.
WrappedOutputStream(java.io.OutputStream stream, int bufferSize)	Constructs a wrapper for the given output stream with the given buffer size.

Method Summary

Modifier and Type	Method	Description
void	close()	Closes the output stream.
void	flush()	Flushes the output buffer, writing all bytes currently in the buffer to the output.
void	flush0()	Flushes the output buffer, writing all bytes currently in the buffer to the output.
void	write(byte[] b, int offset, int length)	Writes an array of bytes to the output.
void	write(int b)	Writes a single byte to the output.

Methods inherited from class java.io.FilterOutputStream

write

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_BUFFER_SIZE

public static final int DEFAULT_BUFFER_SIZE

Default buffer size (1024).

See Also:

Constant Field Values

fBuffer

protected byte[] fBuffer

Buffer.

fPosition

protected int fPosition

Buffer position.

fDataOutputStream

protected java.io.DataOutputStream fDataOutputStream

Data output stream. This stream is used to output the block sizes into the data stream that are read by the WrappedInputStream.

Note: The data output stream is only used for writing the byte count for performance reasons. We avoid the method indirection for writing the byte data.

Constructor Detail

WrappedOutputStream

public WrappedOutputStream(java.io.OutputStream stream)

Constructs a wrapper for the given output stream.

WrappedOutputStream

public WrappedOutputStream(java.io.OutputStream stream,
                           int bufferSize)

Constructs a wrapper for the given output stream with the given buffer size.

Method Detail

write

public void write(int b)
           throws java.io.IOException

Writes a single byte to the output.

Note: Single bytes written to the output stream will be buffered

Overrides:

write in class java.io.FilterOutputStream

Throws:

java.io.IOException

write

public void write(byte[] b,
                  int offset,
                  int length)
           throws java.io.IOException

Writes an array of bytes to the output.

Overrides:

write in class java.io.FilterOutputStream

Throws:

java.io.IOException

flush

public void flush()
           throws java.io.IOException

Flushes the output buffer, writing all bytes currently in the buffer to the output.

Specified by:

flush in interface java.io.Flushable

Overrides:

flush in class java.io.FilterOutputStream

Throws:

java.io.IOException

close

public void close()
           throws java.io.IOException

Closes the output stream. This method must be called when done writing all data to the output stream.

Note: This method does not close the actual output stream, only makes the input stream see the stream closed. Do not write bytes after closing the output stream.

Specified by:

close in interface java.lang.AutoCloseable

Specified by:

close in interface java.io.Closeable

Overrides:

close in class java.io.FilterOutputStream

Throws:

java.io.IOException

flush0

public void flush0()
            throws java.io.IOException

Flushes the output buffer, writing all bytes currently in the buffer to the output. This method does not call the flush() method of the output stream; it merely writes the remaining bytes in the buffer.

Throws:

java.io.IOException