BlockingDeque
The BlockingDeque interface in the java.util.concurrent class represents a deque which is thread safe to put into, and take instances from. In this text I will show you how to use this BlockingDeque.
The BlockingDeque class is a Deque which blocks threads tring to insert or remove elements from the deque, in case it is either not possible to insert or remove elements from the deque.
A deque is short for "Double Ended Queue". Thus, a deque is a queue which you can insert and take elements from, from both ends.
A **BlockingDeque **could be used if threads are both producing and consuming elements of the same queue. It could also just be used if the producing thread needs to insert at both ends of the queue, and the consuming thread needs to remove from both ends of the queue. Here is an illustration of that:
A thread will produce elements and insert them into either end of the queue. If the deque is currently full, the inserting thread will be blocked until a removing thread takes an element out of the deque. If the deque is currently empty, a removing thread will be blocked until an inserting thread inserts an element into the deque.
- LinkedBlockingDeque The LinkedBlockingDeque class implements the BlockingDeque interface. Read the BlockingDeque text for more information about the interface. The word Deque comes from the term "Double Ended Queue". A Deque is thus a queue where you can insert and remove elements from both ends of the queue. The LinkedBlockingDeque is a Deque which will block if a thread attempts to take elements out of it while it is empty, regardless of what end the thread is attempting to take elements from.
BlockingDeque<String> deque = new LinkedBlockingDeque<String>();
deque.addFirst("1");
deque.addLast("2");
String two = deque.takeLast();
String one = deque.takeFirst();