PexQueue v0.1.0 PexQueue View Source

A Queue that uses the First In, First Out (FIFO) method, unless provided with a function to prioritise items.

An example of using the prioritise function might be to order from highest to lowest numbers, regardless of when they are added to the queue. For example, we have this queue:

{:ok, pid} = PexQueue.start_link(fn first, second -> first < second end)
PexQueue.enqueue(pid, 2)
PexQueue.enqueue(pid, 7)
PexQueue.enqueue(pid, 5)

Queue state: [7, 5, 2]

When we add 6 to the queue, it results in:

PexQueue.enqueue(pid, 6)

Queue state: [7, 6, 5, 2]

This is in contrast to a queue with a provided prioritisation function, which would return items in the order they were added.

{:ok, pid} = PexQueue.start_link()
PexQueue.enqueue(pid, 2)
PexQueue.enqueue(pid, 7)
PexQueue.enqueue(pid, 5)

# Queue state: [2, 5, 7]

PexQueue.dequeue(pid) # 2
PexQueue.dequeue(pid) # 5
PexQueue.dequeue(pid) # 7

Link to this section Summary

Functions

count(pid)

Returns the length of the queue

dequeue(pid)

Removes an item from the queue

enqueue(pid, item)

Adds an item to the queue

peek(pid)

Returns the first item in the queue, without altering the queue state

start_link(prioritise \\ fn _, _ -> true end)

Start a new Priority Queue

Link to this section Functions