Array queue is a bounded lock-based FIFO queue using an array. It uses 2 separate locks for head and tail.

Course: Concurrent Data Structures, Monsoon 2020
Taught by: Prof. Govindarajulu Regeti

enq():
1. Lock tail.
2. Try enq.
3. Unlock tail.

deq():
1. Lock head.
2. Try deq.
3. Unlock head.

tryEnq():
1. Ensure queue is not full
2. Save data at tail.
3. Increment tail.

tryDeq():
1. Ensure queue is not empty.
2. Return data at head.
3. Increment head.

## OUTPUT
Starting 10 threads with sequential queue
2: failed enq
5: failed deq
6: failed deq
7: failed deq
8: failed deq
1: failed deq
4: failed deq
9: failed deq
1: dequeued 0/1000 values
2: dequeued 0/1000 values
4: dequeued 0/1000 values
5: dequeued 698/1000 values
6: dequeued 0/1000 values
7: dequeued 0/1000 values
8: dequeued 0/1000 values
9: dequeued 0/1000 values
Was LIFO? false

Starting 10 threads with array queue
Was LIFO? true

See ArrayQueue.java for code, Main.java for test, and repl.it for output.

references

• The Art of Multiprocessor Programming :: Maurice Herlihy, Nir Shavit