control-flow

I am working on a java web application and I have a few questions regarding design. Basically in its current version, it relies heavily on catching exceptions to determine the flow of control . For instance in one of my spring service classes, I have the following method that checks whether an email given as a parameter exists in the database. @Override public boolean validateEmailAddressDoesNotExist(String accountEmailAddress) { try { return !dao.checkIfEmailAddressAlreadyExists(accountEmailAddress); } catch (NoResultException re) { log.error("NoResultException", re); } catch

I have an SSIS package that the first task executes a stored procedure to verify that the run date is not a holiday. If it is a holiday, then it returns a record set with a count of 1. I want to be able to stop the SSIS if the recordcount is 1 but continue to run if the recordcount is zero. I don't know the best way to implement this. What control flow item should I add to the package? I am relatively new to SSIS so I don't know what item to add. Any help would be great. Well one way is to create an Execute SQl task to use that you use to set the value of variable @Holiday. Then change the

I'm looking to be able to yield from a number of async coroutines. Asyncio's as_completed is kind of close to what I'm looking for (i.e. I want any of the coroutines to be able to yield at any time back to the caller and then continue), but that only seems to allow regular coroutines with a single return. Here's what I have so far: import asyncio async def test(id_): print(f'{id_} sleeping') await asyncio.sleep(id_) return id_ async def test_gen(id_): count = 0 while True: print(f'{id_} sleeping') await asyncio.sleep(id_) yield id_ count += 1 if count > 5: return async def main(): runs = [test

The current version of the Pipes tutorial , uses the following two functions in one of the example: stdout :: () -> Consumer String IO r stdout () = forever $ do str <- request () lift $ putStrLn str stdin :: () -> Producer String IO () stdin () = loop where loop = do eof <- lift $ IO.hIsEOF IO.stdin unless eof $ do str <- lift getLine respond str loop As is mentinoed in the tutorial itself, P.stdin is a bit more complicated due to the need to check for the end of input. Are there any nice ways to rewrite P.stdin to not need a manual tail recursive loop and use higher order control flow

I have an IEnumerable<T> . I want to do one thing for each item of the collection, except the last item, to which I want to do something else. How can I code this neatly? In Pseudocode foreach (var item in collection) { if ( final ) { g(item) } else { f(item) } } So if my IEnumerable were Enumerable.Range(1,4) I'd do f(1) f(2) f(3) g(4). NB. If my IEnumerable happens to be length 1, I want g(1). My IEnumerable happens to be kind of crappy, making Count() as expensive as looping over the whole thing. Since you mention IEnumerable[<T>] (not IList[<T>] etc), we can't rely on counts etc: so I

So, I've tried break , next and return . They all give errors, exit of course works, but that completely exits. So, how would one end a case...when "too soon?" Example: case x when y; begin <code here> < ** terminate somehow ** > if something <more code> end end (The above is some form of pseudo-code just to give the general idea of what I'm asking [begin...end was used with the hope that break would work]. And, while I'm at it, is there a more elegant way of passing blocks to case...when ? What's wrong with: case x when y; <code here> if !something <more code> end end Note that if !something

I've used caolan's async module which is very good, however tracking errors and the varying way of passing data through for control flow causes development to sometimes be very difficult. I would like to know if there are any better options, or what is currently being used in production environments. Thanks for reading. I use async as well. To help tracking errors it's recommended you name your functions, instead of having loads of anonymous functions: async.series([ function doSomething() {...}, function doSomethingElse() {...}, function finish() {...} ]); This way you'll get more helpful