org.rhq.cassandra.schema

Class MigrationLog

java.lang.Object

org.rhq.cassandra.schema.MigrationLog

public class MigrationLog
extends Object

An append only log that stores schedule ids in binary format. When data is successfully migrated, the schedule id is written to the log.

Author:

John Sanda

Constructor Summary

Constructors

Constructor and Description
MigrationLog(File logFile)

Method Summary

Methods

Modifier and Type	Method and Description
void	close() Flushes any buffered writes and then closes the underlying output stream.
Set<Integer>	read() Sequentially reads the log into a set.
void	write(int scheduleId) Appends scheduleId to the log.

Methods inherited from class java.lang.Object

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

Constructor Detail

MigrationLog

public MigrationLog(File logFile)
             throws IOException

Throws:

IOException

Method Detail

read

public Set<Integer> read()
                  throws IOException

Sequentially reads the log into a set. If the log is empty or does not yet exist, an empty set is returned. This method does not support concurrent access.

Throws:

IOException

write

public void write(int scheduleId)
           throws IOException

Appends scheduleId to the log. Writes go to an internal buffer and are not immediately flushed to disk. When the buffer fills up, it is automatically flushed. This method supports concurrent access.

Throws:

IOException

close

public void close()
           throws IOException

Flushes any buffered writes and then closes the underlying output stream.

Throws:

IOException