DelegateDispatcher

DelegateDispatcher.md

DelegateDispatcher

Create an interface to receive delegate callback and dispatch to muitpule observer instances.

Usage

For example, we create an delegate called MyClassDelegate.

protocol MyClassDelegate {
    func myClassDosomething()
}

First, create a dispatcher with your delegate type.

class MyDispatcher {
    static let sharedInstance = MyDispatcher()
    private let dispatcher = DelegateDispatcher<MyClassDelegate>()
}

Second, pipe the original delegate into your dispatcher.

extension MyDispatcher: MyClassDelegate {
    func myClassDosomething() {
        for obj in dispatcher.getObservers() {
            obj.myClassDosomething()
        }
    }
}

Then, add your class to dispatcher observers.

class MyClass1: MyClassDelegate {
    
    func registerObserver() {
        MyDispatcher.sharedInstance.dispatcher.addWeakObserver(self)
    }
    
    func myClassDosomething() {
        // ...
    }
}

class MyClass2: MyClassDelegate {
    
    func registerObserver() {
        MyDispatcher.sharedInstance.dispatcher.addWeakObserver(self)
    }
    
    func myClassDosomething() {
        // ...
    }
}

DelegateDispatcher.swift

import Foundation

class DelegateDispatcher<T> {
    private let weakObservers = NSPointerArray.weakObjects()
    
    func addWeakObserver(_ observer: T) {
        let pointer = UnsafeMutableRawPointer(Unmanaged.passUnretained(observer as AnyObject).toOpaque())
        weakObservers.addPointer(pointer)
    }
    
    func compact() {
        weakObservers.compact()
    }
    
    func getObservers() -> [T] {
        weakObservers.compact()
        return (weakObservers.allObjects as? [T]) ?? []
    }
}