observer-pattern

I've been looking over the internet for examples of implementing the observer pattern in jquery. I would like to have it like this observer1.observe(subject); observer2.observe(subject); Define some custom event callbacks for the observers observer1.bind('customEvent', function(contextData) { //Some code }); observer1.bind('anotherCustomEvent', function(contextData) { //Some code }); observer2.bind('customEvent', function(contextData) { //Some code }); The following line would then trigger the customEvent callbacks of both observers subject.trigger('customEvent', contextData); while the

Greetings, in Magento I want to trigger an event, once an order has been set to processing (by gateway confirmation or manually) that, example: If a general customer (id 1) spends over 100$ and the payment has been confirmed, set his group id to 4 (silver VIP, which by promotion rule gets 2% discount globally) I would give a bounty to this, but I'd like the answer before 2 days O_o EDIT : the answer I received so far is only a partial answer, also I find the links very confusing, I'm not clear on what is the minimal setup, what do i have to configure create etc... Also I'm trying to find out

I am learning Observer pattern, I want my observable to keep track of a certain variable when it changes it's value and do some operations, I've done something like : public class Test extends MyChildActivity { private int VARIABLE_TO_OBSERVE = 0; Observable<Integer> mObservable = Observable.just(VARIABLE_TO_OBSERVE); protected void onCreate() {/*onCreate method*/ super(); setContentView(); method(); changeVariable(); } public void changeVariable() { VARIABLE_TO_OBSERVE = 1; } public void method() { mObservable.map(value -> { if (value == 1) doMethod2(); return String.valueOf(value); })

i thought about using observers or callbacks. What and when you should use an observer? F.e. you could do following: # User-model class User << AR after_create :send_greeting! def send_greeting! UserNotifier.deliver_greeting_message(self) end end #observer class UserNotifier << AR def greeting_message(user) ... end end or you could create an observer and let it watch when users becomes created... What dou you recommened? A callback is more short lived: You pass it into a function to be called once. It's part of the API in that you usually can't call the function without also passing a callback

We recently began a compliance push at our company and are required to keep a full history of changes to our data which is currently managed in a Rails application. We've been given the OK to simply push something descriptive for every action to a log file, which is a fairly unobtrusive way to go. My inclination is to do something like this in ApplicationController : around_filter :set_logger_username def set_logger_username Thread.current["username"] = current_user.login || "guest" yield Thread.current["username"] = nil end Then create an observer that looks something like this: class

I've noticed that my dependency injected, observer-pattern-heavy code (using Guava's EventBus ) is often significantly more difficult to debug than code I've written in the past without these features. Particularly when trying to determine when and why observer code is being called. Martin Oderski and friends wrote a lengthy paper with an especially alluring title, "Deprecating the Observer Pattern" and I have not yet made the time to read it. I'd like to know what is so wrong with the observer pattern and so much better about the (proposed or other) alternatives to lead such bright people to