ninja.activeproxy.path.io
Class PathInputStream

java.lang.Object
  |
  +--java.io.InputStream
        |
        +--ninja.activeproxy.path.io.PathInputStream

public class PathInputStream

extends java.io.InputStream

The PathInputStream 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

java.io.InputStream	inputStream
Operator	operator
java.lang.Object	pathID
boolean	rebuildFlag

Fields inherited from class java.io.InputStream

SKIP_BUFFER_SIZE, skipBuffer

Constructor Summary

PathInputStream()
Default constructor

PathInputStream(Operator operator, java.lang.Object pathID, java.io.InputStream inputStream)
Create a new PathInputStream from the provided input stream.

Method Summary

int	available()
void	close() Same as default InputStream close method
void	mark(int readlimit) Same as default InputStream mark method
boolean	markSupported() Same as default InputStream markSupported method
int	read() The read method -- called too handle data input on this stream.
int	read(byte[] b) Try to fill array b with data.
void	reset() Same as default InputStream reset method
long	skip(long n) fill b with data, starting at offset off and for len bytes

Methods inherited from class java.io.InputStream

read

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

inputStream

public java.io.InputStream inputStream

rebuildFlag

public boolean rebuildFlag

Constructor Detail

PathInputStream

public PathInputStream()

Default constructor

PathInputStream

public PathInputStream(Operator operator,
                       java.lang.Object pathID,
                       java.io.InputStream inputStream)

Create a new PathInputStream from the provided input 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.

inputStream - The stream which we're wrapping

Method Detail

read

public int read()
         throws java.io.IOException

The read method -- called too handle data input on this stream.

Basically works as follows:

1) call inputStream.read() to block for incoming data

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:

read in class java.io.InputStream

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.

read

public int read(byte[] b)
         throws java.io.IOException

Try to fill array b with data.

Overrides:

read in class java.io.InputStream

Parameters:

b - An array of bytes to fill with data

Throws:

IOException, - see int read()<\i> above.

skip

public long skip(long n)
          throws java.io.IOException

fill b with data, starting at offset off and for len bytes

Overrides:

skip in class java.io.InputStream

Parameters:

b - The array to put data into

off - The offset to being writing data at

len - The number of bytes to read

available

public int available()
              throws java.io.IOException

Overrides:

available in class java.io.InputStream

close

public void close()
           throws java.io.IOException

Same as default InputStream close method

Overrides:

close in class java.io.InputStream

mark

public void mark(int readlimit)

Same as default InputStream mark method

Overrides:

mark in class java.io.InputStream

reset

public void reset()
           throws java.io.IOException

Same as default InputStream reset method

Overrides:

reset in class java.io.InputStream

markSupported

public boolean markSupported()

Same as default InputStream markSupported method

Overrides:

markSupported in class java.io.InputStream