Normally, when the log file is rolled the file name extension is not preserved.
For example, file.log is rolled to file.log.1 or file.log.yyyy-MM-dd.
However, this may not be desired in all cases and it may be necessary to preserve the log file name extension when the log file is rolled. Most notably, this feature is useful for maintaining file associations under Windows so that all log files can be associated with a particaular text viewer.
For example, file.log is rolled to file.1.log or file.yyyy-MM-dd.log.
This patch adds an additional boolean property PreserveLogFileNameExtension to the RollingFileAppender class which is used to toggle this behavior.