I'm trying to wrap my head around different concurrency solutions to several threads iterating over the same collection but I'm having difficulty coming up with good realistic (but preferably easy to model) scenarios to  code against. I'm looking for realistic scenarios for:A scenario where several threads can iterate over a collection simultaneously and lock      each item as it comes to it and do some modification, item's can't be visible in a partially updated stateA scenario where different threads try to iterate over a collection but only one at a time should be allowed toA scenario where several threads might iterate over a collection for reading, but only one thread might iterate for writingAny other nice concurrency iterating scenarios you might come up with are welcome as well :) thanks!
Examples of concurrent iterating scenarios needed
multithreading;parallelism;concurrency