Support of Periodic Reloading 
Use
The SAP Logging API provides options for dealing with log assignment (additive) with periodic reloading. This section covers only the general behavior, not the technical details.
The use of an optional ‘+’, for example:
com.sapmarkets.foo.logs = + log[Console] |
· The general rule of thumb – with the presence of a new log(s) configuration, without the ‘+’, the logs of the log controller that are already assigned are discarded, while with the ‘+’, the new logs are added to the existing list of logs.
Configuration Unchanged
When the configuration remains unchanged (which is typical once a stable configuration has been defined), the use of ‘+’ is not significant. No further action is done and the objects that were already attached are still attached. This avoids the loss of state of the attached objects.
Configuration Changed
The typical configuration updates include: changing the log destination, adding a log destination and modifying the properties of an existing log. The first two cases are straightforward (see Change Output Logs / Filters).
If you have already assigned logX to a location, to change the destination to logY in the next reloading, proceed as follows in the configuration file:
com.sapmarkets.foo.logs = logY |
logX is removed.
To add to the existing logX:
com.sapmarkets.foo.logs = + logY |
Both logX and logY persist.
The last type of modification (changing properties) mainly applies to the FileLog as it has a number of attributes. The FileLog is identified by its ‘pattern’, therefore, a new pattern means a new log. This has a behavior similar to changing log destination and adding log destination. The ‘+’ is important.
If the changes are on the other attributes, for example limit or cnt, the ‘+’ is not significant, no new FileLog will be created. The existing FileLog remains and will be modified with the corresponding new attribute values.
Do not use the ‘+’, or use it for all occurrences of the log assignments.