Systems and methods for web store events. A web store event occurs
whenever an item is accessed. When an item is accessed, both synchronous
and asynchronous events can fire. If a synchronous event fires, then an
event object that has registered for the synchronous event is called and
executed before the transaction involving the item is allowed to
complete. The synchronous event also has the ability to either commit or
abort the transaction. Importantly, the synchronous event has complete
control over the item. An asynchronous event is called and executed after
the transaction involving the item is already committed to the store and
after any synchronous events have executed. Because more than one event
object can register for a web store event, synchronous event objects are
called according to their priority. Synchronous events fire before
asynchronous events and synchronous event objects execute before
asynchronous event objects.