com.bigdata.journal

Interface ISnapshotFactory

All Known Implementing Classes:

BasicSnapshotFactory

public interface ISnapshotFactory

Interface allows an application to decide on the file name for the snapshot, whether or not the snapshot will be compressed, etc.

Author:

bryan

See Also:

Online backup for Journal

Method Summary

Methods

Modifier and Type	Method and Description
boolean	getCompress() When true the generated snapshot will be compressed.
File	getSnapshotFile(IRootBlockView rbv) Return the File on which the snapshot will be written.

Method Detail

getSnapshotFile

File getSnapshotFile(IRootBlockView rbv)
                     throws IOException

Return the File on which the snapshot will be written. A common strategy is to label each snapshot with the commit counter from the associated root block and place the snapshots within some directory known to the application. E.g., "snapshots/snapshot-commitCounter.jnl". If the snapshot is to be compressed, then the best practice is to have the file name end with ".gz". See the CommitCounterUtility for helper classes for dealing with commit counters as fixed width strings.

Parameters:

rbv - The current root block. The snapshot will be consistent as of the commit point associated with this root block.

Returns:

The file on which the snapshot will be written. If the file exists, then it must be empty. If the file is in a directory, the directory must exist and must be writable.

Throws:

IOException

See Also:

CommitCounterUtility

getCompress

boolean getCompress()

When true the generated snapshot will be compressed.