com.elvishew.xlog.printer.file.backup

Interface BackupStrategy2

All Superinterfaces:

BackupStrategy

All Known Implementing Classes:

AbstractBackupStrategy, BackupStrategyWrapper, FileSizeBackupStrategy2

public interface BackupStrategy2
extends BackupStrategy

Decide whether and how the log file should be backed up and use a new file for next logging.

Since:

1.9.0

Field Summary

Fields

Modifier and Type	Field and Description
static int	NO_LIMIT Don't limit the backup index, which means there is no limit to the number of backup files.

Method Summary

Modifier and Type	Method and Description
java.lang.String	getBackupFileName(java.lang.String fileName, int backupIndex) Get the backup file name for specific index.
int	getMaxBackupIndex() Get the max index of backup.

Methods inherited from interface com.elvishew.xlog.printer.file.backup.BackupStrategy

shouldBackup

Field Detail

NO_LIMIT

static final int NO_LIMIT

Don't limit the backup index, which means there is no limit to the number of backup files.

See Also:

Constant Field Values

Method Detail

getMaxBackupIndex

int getMaxBackupIndex()

Get the max index of backup.

Generally, the max index should be greater than 1, and recommended to be less than 10.

Imagine the normal log file name is 'log', and max backup index is 'n', as the log grows, a log record would go from 'log' to 'log.bak.1', then to 'log.bak.2', 'log.bak.3', and finally to 'log.bak.n', the greater index, the older log.
After that, the log record will no longer exist in the file system.

If you don't want to limit the max index, then return NO_LIMIT.
With returning NO_LIMIT, When you backing up, the oldest log would be saved to 'log.bak.1', and then 'log.bak.2'...'log.bak.n', the greater index, the newer log.

Don't return Integer.MAX_VALUE or any value less than 0, otherwise an exception will be thrown.

Returns:

the max index of backup

getBackupFileName

java.lang.String getBackupFileName(java.lang.String fileName,
                                   int backupIndex)

Get the backup file name for specific index.

Generally, a backup file with normal file name 'log' and index 'n' could simply be 'log.bak.n', you can specify your own naming rules, by overriding this method.

Make sure to return different backup file name with different backup index, and same backup file name with same index. Otherwise, it will lead to unexpected behavior.

Parameters:

fileName - the normal file name, generated by FileNameGenerator.generateFileName(int, long)

backupIndex - the backup index, which will increase from 1 to getMaxBackupIndex()

Returns:

the backup file name