Question

The customer wants us to ‘log’ the ‘actions’ that a user performs on our system: creation, deletion and update, mostly. I already have an aspect that logs the trace, but that works at a pretty low level logging every method call. So if a user clicked on the button ‘open medical file’ the log would read:

1. closePreviousFiles(‘patient zero’)
2. createMedicalFile(‘patient zero’) –> file #001
3. changeStatus(‘#001’) –> open

while the desired result is:

1. opened medical file #001 for patient zero

I’m thinking of instrumenting the Struts2 actions with log statements, but I’m wondering… is there another way to do that? I might use AspectJ again (or a filter) and keep the logic in just one place, so that I might configure the log easily, but then I’m afraid everything will become harder to understand (i.e. ‘the log for this action is wrong… where the heck should I look for the trouble?’).

Answer 1

Sounds like your client wants an audit trail of the user’s actions in the system.

Consider that at each action’s entry point (from the web request) to start an audit entry with an enum/constant on the action. Populate it with information user has provided if possible.

At exit/finally, indicate in the audit if it is successful or failed. An example in pseudocode:

enum Actions {   OPEN_MEDICAL_FILE   ... }  void handleRequest(...) {   String patient = ...;   Audit audit = new Audit(OPEN_MEDICAL_FILE);   audit.addParameter('patient', patient);   try {      ... more things ..      audit.addParameter('file', '#001');      ... more things ...      audit.setSuccess();   } finally {     audit.save();   } } 

What is important here is that all user actions are saved, regardless of success or failure. Also, the client really really need to know all relevant information along with the action.

Since we are logging action constants and data, the presentation of the audit to the client can be seperately coded. You gain flexibility too, since a change of presentation string (eg. ‘opened medical file #001 for patient zero’ to ‘patient zero #001 medical file opened) is not determined at the time of the action, but later. You don’t have to remassage the audit data.