com.elvishew.xlog.internal.printer.file.backup

Class BackupStrategyWrapper

java.lang.Object

com.elvishew.xlog.internal.printer.file.backup.BackupStrategyWrapper

All Implemented Interfaces:

BackupStrategy, BackupStrategy2

public class BackupStrategyWrapper
extends java.lang.Object
implements BackupStrategy2

Wrap a BackupStrategy to fit the BackupStrategy2 interface, and perform like a BackupStrategy with the old logic before v1.9.0.

Field Summary

Fields inherited from interface com.elvishew.xlog.printer.file.backup.BackupStrategy2

NO_LIMIT

Constructor Summary

Constructors

Constructor and Description
BackupStrategyWrapper(BackupStrategy backupStrategy)

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.
boolean	shouldBackup(java.io.File file) Whether we should backup a specified log file.

Methods inherited from class java.lang.Object

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

Constructor Detail

BackupStrategyWrapper

public BackupStrategyWrapper(BackupStrategy backupStrategy)

Method Detail

getMaxBackupIndex

public int getMaxBackupIndex()

Description copied from interface: BackupStrategy2

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 BackupStrategy2.NO_LIMIT.
With returning BackupStrategy2.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.

Specified by:

getMaxBackupIndex in interface BackupStrategy2

Returns:

the max index of backup

getBackupFileName

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

Description copied from interface: BackupStrategy2

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.

Specified by:

getBackupFileName in interface BackupStrategy2

Parameters:

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

backupIndex - the backup index, which will increase from 1 to BackupStrategy2.getMaxBackupIndex()

Returns:

the backup file name

shouldBackup

public boolean shouldBackup(java.io.File file)

Description copied from interface: BackupStrategy

Whether we should backup a specified log file.

Specified by:

shouldBackup in interface BackupStrategy

Parameters:

file - the log file

Returns:

true is we should backup the log file