#ENQUEUE AND DEQUEUE IN JAVA CODE#

This does make sense to me - the enqueuer knows what it's adding, the dequeuer only finds out what it gets after doing the dequeue. Nowadays, stack-like behavior is supported by the primitive 'Enqueue at Opposite End' which places the enqueued element directly at the front of the queue.Įxactly *why* the change was made I cannot say, but I can notice that it shifts *responsibility* for choosing stack-like behavior from the dequeue side over to the enqueue side.

I'd venture that the 'Remove from End' parameter was an early attempt to support optional stack-like behavior.

#ENQUEUE AND DEQUEUE IN JAVA CODE#

If you can't figure it out, you could just post the old code so we could see it. Personally I'd recommend trying to determine what led the original programmer to think this was a good idea, and either switch to a data structure that makes more sense for the use case or find a different way to deal with whatever the last element of the queue was needed for. You'll also have to be certain you don't have any other operations running in parallel that might insert another item in the queue while you're doing it, so you might need to add a Semaphore or other control mechanism like it to lock down the queue during the improvised 'remove from end' that you've just added.

If you DO want to use this, the closest way is to use 'Flush queue' to remove all the elements as an array, remove the last element, and then enqueue the rest all over again in the same order. Taking things from the opposite end means you either should have used the 'enqueue element at opposite end' function, or that your code is doing some sort of screening or modification of the queue elements, which you should solve by having multiple parallel queues or a different data structure entirely. A queue is for any number of locations to write things to, which are then run in order by one and just one section of code. Well at a guess it probably said something like 'we removed this because it's missing the point of using a queue entirely'.

Enqueue and dequeue in java