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PriorityQueue

Framework with data structure and protocol to serve elements in order by priority

Overview

The PriorityQueue is a prioritized element collection. It provides quick access the highest priority element. An element with high priority is served before an element with low priority. If two elements have the same priority, they are served according to their order in the queue.

The PriorityType data structure is backed arrays that hold alike priority elements together. The number of arrays is equal to 3 corresponding to the number of cases of in Priority enum. This adds the ability to add like priority elements by index and have like elements being served in a specific order as well.

// PriorityQueue class internal collections
var highPriorityCollection = [PriorityType]()
var defaultPriorityCollection = [PriorityType]()
var lowPriorityCollection = [PriorityType]()

The PriorityQueue elements must adhere to PriorityType which adds an associated "priority" to each element.

Requirements

Xcode 8

Swift 3.1

iOS 8.0+

Code Example

Creating a queue

let priorityQueue = PriorityQueue()

Adding an element

let foo = Foo(priority: .high, value: 0)
priorityQueue.add(item: foo)

Create an element that adheres to the PriorityType protocol

struct Foo: PriorityType {
    var priority: Priority
    let value: Int
}

Insert an element

let foo = Foo(priority: .high, value: 0)
priorityQueue.insert(item: foo)

Insert an element at a specified position in its corresponding priority collection.

let foo = Foo(priority: .high, value: 0)
priorityQueue.insert(item: foo, at: 2) // inserted at index 2 in the collection of high priority alike elements

Remove all elements from the queue

priorityQueue.removeAll()

Get top item

let top = priorityQueue.getTopItem() // returns a PriorityType object

Get top object (casted)

let topFoo: Foo? = priorityQueue.getTopObject() // returns Foo object

Installation

@available(iOS 8, *)

Swift Package Manager

import PackageDescription

let package = Package(
    name: "YourProject",
    targets: [],
    dependencies: [
        .Package(url: "https://github.com/lostatseajoshua/PriorityQueue.git",
                 majorVersion: 1)
    ]
)

Manually

To use this library in your project manually do the following.

Add the PriorityQueue.framework to your project by downloading the framework from the releases

Contributors

Joshua Alvarado - Twitter

License

This project is released under the MIT license.