Consider the following example
class ClassA {
func createAnInstanceOfAnotherClass() -> AnotherClass {
return AnotherClass()
}
func callMeA() {
}
}
class ClassB {
func createAnInstanceOfAnotherClass() -> AnotherClass {
return AnotherClass()
}
func callMeB() {
}
}
class AnotherClass {
func doSomethingAndReturn() {
return
}
}
class MethodChain {
func methodChainTest() {
ClassA()
.createAnInstanceOfAnotherClass()
.doSomethingAndReturn() //return to ClassA
.callMeA() // call classA callMe
ClassB()
.createAnInstanceOfAnotherClass()
.doSomethingAndReturn() // return to ClassB
.callMeB() // call ClassB callMe
}
}
Is it possible for the class AnotherClass to return the instance of the class that created it? In this example I want to use the class method doSomethingAndReturn when method chaining with both ClassA and ClassB and then contione the method chain with methods from either ClassA or ClassB
You could make AnotherClass generic with a type parameter Creator, which stores the type of its creator.
class ClassA {
func createAnInstanceOfAnotherClass() -> AnotherClass<ClassA> {
return AnotherClass(creator: self)
}
func callMeA() {
}
}
class ClassB {
func createAnInstanceOfAnotherClass() -> AnotherClass<ClassB> {
return AnotherClass(creator: self)
}
func callMeB() {
}
}
class AnotherClass<Creator: AnyObject> {
// weak to avoid retain cycles!
private weak var creator: Creator?
init(creator: Creator) {
self.creator = creator
}
func doSomethingAndReturn() -> Creator {
// assuming you always do method chaining,
// and not do something weird with the intermediate results,
// this should be safe to unwrap forcefully
creator!
}
}