AssociatedObjectOwnerの利用
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| class TestClass {
}
extension TestClass: AssociatedObjectOwner {
private static var test1Key = 0
var test1: TestClass {
get { getAssociatedObject(key: &TestClass.test1Key, initialObject: TestClass()) }
set { setAssociatedObject(key: &TestClass.test1Key, object: newValue) }
}
private static var test2Key = 0
var test2: String {
get { getAssociatedObject(key: &TestClass.test2Key, initialObject: "" ) }
set { setAssociatedObject(key: &TestClass.test2Key, object: newValue) }
}
}
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AssociatedObjectOwner定義
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| protocol AssociatedObjectOwner: AnyObject {
func getAssociatedObject<T>(key: UnsafeRawPointer, initialObject: @autoclosure () -> T) -> T
func setAssociatedObject<T>(key: UnsafeRawPointer, object: T?)
}
extension AssociatedObjectOwner {
func getAssociatedObject<T>(key: UnsafeRawPointer, initialObject: @autoclosure () -> T) -> T {
if let object = objc_getAssociatedObject(self, key) as? T {
return object
}
let object = initialObject()
objc_setAssociatedObject(self, key, object, .OBJC_ASSOCIATION_RETAIN_NONATOMIC)
return object
}
func setAssociatedObject<T>(key: UnsafeRawPointer, object: T?) {
objc_setAssociatedObject(self, key, object, .OBJC_ASSOCIATION_RETAIN_NONATOMIC)
}
}
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