Let we assume that we have several information on the Ethereum Blockchain and we want to realize some kind of a governance. For the first run, we want to collect and monitor the information who had access to some of the critical data and when. The easiest way is to implement an event type for logging. It provides both the possibility to log into a specific storage area and the possibility that the event is raised online on the client side (for instance in a javascript UI).
Triggering the events can be done the best by modifiers, like one for read and one for write.
Lat but not least, the functions that are critical, like access to the critical variable in this example can be extended by the modifiers.
Certainly, the pattern works much better with inheritance, like implementing the modifiers in an ancestor smart contract and simply using them in a descendant contract. It is important to note that Ethereum is a public Blockchain. As a consequence, in this example even if getVariable is explicitly logged, there is a little bit hacking way to read out the information from the ledger itself without using getVariable.
