lazy-initialization

Quick question... Well I understand that all properties start out as nil in Objective-C and that sending a message to nil does nothing, therefore you must initialize using [[Class alloc] init]; before sending a message to a newly created property. However, what about if I'm not sending messages to this property or if I set the property using self.property = something? Do I need to alloc init in these cases as well? Also, do UI properties start out as nil as well, such as a UILabel property that you drag out from your storyboard? Do these need alloc init? Thanks to all who answer Jason C.

I would like to implement lazy field initialization (or deferred initialization) without an if statement and taking advantage of lambdas. So, I would like to have the same behavior of the following Foo property but without the if : class A<T>{ private T fooField; public T getFoo(){ if( fooField == null ) fooField = expensiveInit(); return fooField; } } Ignore the fact that this solution is not guaranteeing safe use for: 1) multi-threading; 2) null as a valid value of T . So, to express the intention that the initialization of the fooField is deferred until its first use I would like to declare

Is there a way to implement a singleton object in C++ that is: Lazily constructed in a thread safe manner (two threads might simultaneously be the first user of the singleton - it should still only be constructed once). Doesn't rely on static variables being constructed beforehand (so the singleton object is itself safe to use during the construction of static variables). (I don't know my C++ well enough, but is it the case that integral and constant static variables are initialized before any code is executed (ie, even before static constructors are executed - their values may already be

Would like to hear experts on best practice of editing JPA entities from JSF UI. So, a couple of words about the problem. Imagine I have the persisted object MyEntity and I fetch it for editing. In DAO layer I use return em.find(MyEntity.class, id); Which returns MyEntity instance with proxies on "parent" entities - imagine one of them is MyParent . MyParent is fetched as the proxy greeting to @Access(AccessType.PROPERTY) : @Entity public class MyParent { @Id @Access(AccessType.PROPERTY) private Long id; //... } and MyEntity has the reference to it: @ManyToOne(fetch = FetchType.LAZY)

I have something that really puzzles me, specifically the following code triggers a compiler error "unresolved identifier self", and I am not sure why this is happening, as lazy means that at the time the property will be used, the class is already instantiated. Am I missing something? Many thanks in advance. Here is the code class FirstClass { unowned var second: SecondClass init(second:SecondClass) { self.second = second print("First reporting for duty") } func aMethod() { print("First's method reporting for duty") } } class SecondClass { lazy var first = FirstClass(second: self) func

I am working on a project for a customer who wants to use lazy initialization. They always get "lazy initialization exception" when mapping classes with the default lazy loading mode. @JoinTable(name = "join_profilo_funzionalita", joinColumns = {@JoinColumn(name = "profilo_id", referencedColumnName = "profilo_id")}, inverseJoinColumns = {@JoinColumn(name = "funzionalita_id", referencedColumnName = "funzionalita_id")}) //@ManyToMany(fetch=FetchType.EAGER) - no exceptions if uncommented @ManyToMany private Collection<Funzionalita> funzionalitaIdCollection; Is there a standard pattern using JPA