com.atomikos.persistence
Interface LogStream

All Known Implementing Classes:

FileLogStream

public interface LogStream

The LogStream interface is an abstract definition of a stream that encapsulates a physical log. In contrast to a regular input or output stream, a log stream has both input and output facilities to the same underlying log. It also allows for checkpointing, but the client is responsible for determining the checkpoint contents. Checkpointing allows the log stream to decrease in size.

Method Summary

void	close() For proper termination: a close method.
void	flushObject(Object objectToFlush, boolean shouldSync) Flush (force) an object to the stream.
long	getSize() Get the size of the stream.
Vector	recover() Reads the log contents, and initializes the data structure.
void	writeCheckpoint(Enumeration elements) After intial recovery, it is good practice to write a checkpoint with only the most recent data.

Method Detail

getSize

long getSize()
             throws LogException

Get the size of the stream.

Returns:

long The size of the stream.

Throws:

LogException - On error.

recover

Vector recover()
               throws LogException

Reads the log contents, and initializes the data structure. Should be called first.

Returns:

Vector The read objects from the log.

Throws:

LogException - On failure.

writeCheckpoint

void writeCheckpoint(Enumeration elements)
                     throws LogException

After intial recovery, it is good practice to write a checkpoint with only the most recent data. This method does that, and can also be called at random intervals during normal operation.

Parameters:

elements - The elements to keep in the log.

Throws:

LogException - On failure.

flushObject

void flushObject(Object objectToFlush,
                 boolean shouldSync)
                 throws LogException

Flush (force) an object to the stream. If this method returns then the object is guaranteed to be persisted.

Throws:

LogException - On failure.

close

void close()
           throws LogException

For proper termination: a close method.

Throws:

LogException - On failure.