ninja.activeproxy.path.io
Class PathOutputStream

java.lang.Object
  |
  +--java.io.OutputStream
        |
        +--ninja.activeproxy.path.io.PathOutputStream

public class PathOutputStream

extends java.io.OutputStream

The PathOutputStream is a wrapper for a standard java InputStream which handles failure detection and recovery for Ninja paths. The general process for doing this is as follows: When an exception occurs on input or output, notify the operator passed into the constructor by calling the operator.pathFailed exception. This operator is considered to be the "path master" and is responsible for rebuilding part or all of the path when it is notified of an error.

Field Summary

Operator	operator
java.io.OutputStream	outputStream
java.lang.Object	pathID
boolean	rebuildFlag

Constructor Summary

PathOutputStream()
Default constructor

PathOutputStream(Operator operator, java.lang.Object pathID, java.io.OutputStream outputStream)
Create a new PathOutputStream from the provided output stream.

Method Summary

void	close()
void	flush()
void	write(byte[] b)
void	write(byte[] b, int off, int len)
void	write(int b) The write method -- called too handle data output on this stream.

Methods inherited from class java.lang.Object

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

Field Detail

operator

public Operator operator

pathID

public java.lang.Object pathID

outputStream

public java.io.OutputStream outputStream

rebuildFlag

public boolean rebuildFlag

Constructor Detail

PathOutputStream

public PathOutputStream()

Default constructor

PathOutputStream

public PathOutputStream(Operator operator,
                        java.lang.Object pathID,
                        java.io.OutputStream outputStream)

Create a new PathOutputStream from the provided output stream.

Parameters:

operator - The master operator for this path; should be notified on path failure

pathID - The pathID which this stream belongs to -- needs to be kept so the appropriate message can be passed to the pathFailed method of the path owner.

outputStream - The stream which we're wrapping

Method Detail

write

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

The write method -- called too handle data output on this stream.

Basically works as follows:

1) call outputStream.write() to push the specified byte onto the stream

2) if an exception occurs, call the pathFailed method of the path master

3) if the path was rebuilt, throw a "PathInterruptedException" to the stream owner

4) if the path was unable to be rebuilt, thrown a "NoPathFoundException"

Overrides:

write in class java.io.OutputStream

Parameters:

b - A byte of data to write

Throws:

java.io.IOException - which is either:

PathInterruptedException: The stream owner is being notified that the path had to be rebuilt and some data may have been lost. It is currently the responsibility of the path owner to hand end-to-end delivery constraints

NoPathFoundException: The stream could not be or was not rebuilt, but isn't allowing data to flow properly. The stream owner is basically SOL, but should attept to clean up and fail gracefully.

write

public void write(byte[] b)
           throws java.io.IOException

Overrides:

write in class java.io.OutputStream

write

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

Overrides:

write in class java.io.OutputStream

flush

public void flush()
           throws java.io.IOException

Overrides:

flush in class java.io.OutputStream

close

public void close()
           throws java.io.IOException

Overrides:

close in class java.io.OutputStream