note 57316 deleted from language.oop5.patterns by danbrown

Note Submitter: rashkatsa ---- Hi there, As Singleton patterns are used for years in Java, today we tend toward overriding 'new' operator (as singleton returns always the same instance for every 'new' that you call...). In order to do this, we use IoC (http://www.martinfowler.com/articles/injection.html). With lightweight container, you delegate the 'new' to a specific factory which decides if it has to return a new instance on each call or always the same instance. You homogenize your code as you don't have "new MyClass()" and "MyClass2::getInstance()" but always the same call : Component::get(MyClass) and Component::get(MyClass2). [PHP implementation hint : You can choose the parameter of the get method : class, classname, ...]. It's the component which decides if it has to return a new instance or not. If you take a look at Java Spring framework (which use getBean(Class) method) or PicoContainer (which use getComponentInstance(Class) method - see 2 minutes tutorial on their site), you can configure the behavior for your class in an XML file (choosing that ClassA is a singleton and ClassB is not). With this configuration, you don't need to pollute your class code with _instance field but you just create a standard class (non invasive pattern). when you would have a PHP generic component (class) factory, you can go further and build a complete PHP IoC (if it not already exists :)) and then the component factory injects dependencies itself (choose through constructors or mutators). regards, rashkatsa.