olbrichj

let op1 = Operation1()
let op2 = Operation2()


let adapter = BlockOperation() { [unowned op1, unowned op2] in
    op2.data = op1.data
}

adapter.addDependency(op1)
op2.addDependency(adapter)

olbrichj

import Foundation

class OperationObserver: NSObject {
    init(operation: AsyncOperation) {
        super.init()
        operation.addObserver(self, forKeyPath: "finished", options: .new, context: nil)
    }
    
    override func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey : Any]?, context: UnsafeMutableRawPointer?) {
        guard let key = keyPath else {

olbrichj

import Foundation

class HelloWorldOperation: GroupOperation {
    override init() {
        super.init()
        
        let op = TextOperation(text: "Hello")
        let op2 = TextOperation(text: "World")

        op2.addDependency(op)

olbrichj

import Foundation

class GroupOperation: AsyncOperation {
    let queue = OperationQueue()
    var operations: [AsyncOperation] = []
    
    override func execute() {
        print("group started")
        queue.addOperations(operations, waitUntilFinished: true)
        print("group done")

olbrichj

import Foundation

class TextOperation: AsyncOperation {
    let text: String
    
    init(text: String) {
        self.text = text
    }
    
    override func execute() {

olbrichj

import Foundation

class AsyncOperation: Operation {
    override var isAsynchronous: Bool {
        return true
    }
    
    var _isFinished: Bool = false
    
    override var isFinished: Bool {

olbrichj

let op1 = Operation()

op.completionBlock = {
    print("done")
}

olbrichj

precedencegroup OperationChaining {
    associativity: left
}
infix operator ==> : OperationChaining

@discardableResult
func ==><T: Operation>(lhs: T, rhs: T) -> T {
    rhs.addDependency(lhs)
    return rhs
}

olbrichj

let op = DemoOperation()
OperationQueue.addOperations([op], waitUntilFinished: false)

op.cancel()

olbrichj

let operationQueue: OperationQueue = OperationQueue()
operationQueue.maxConcurrentOperationCount = 1