Wait for all Operations in queue to finish before performing task

Question

I have an Operation subclass and Operation queue with maxConcurrentOperationCount = 1.

This performs my operations in a sequential order that i add them which is goo

Answer 1

My solution is similar to that of https://stackoverflow.com/a/42496559/452115, but I don't add the completionOperation in the main OperationQueue but into the queue itself. This works for me:

var a = [Int](repeating: 0, count: 10)

let queue = OperationQueue()

let completionOperation = BlockOperation {
    print(a)
}

queue.maxConcurrentOperationCount = 2
for i in 0...9 {
    let operation = BlockOperation {
        a[i] = 1
    }
    completionOperation.addDependency(operation)
    queue.addOperation(operation)
}

queue.addOperation(completionOperation)

print("Done