In my application I have many classes. Most of these classes store quite some data, and it is important that other modules in my application are also 'updated' if the content of one of the data classes changes. The typical way to do this is like this: void MyDataClass::setMember(double d) { m_member = d; notifyAllObservers(); } This...
Below is my code config.xml <?xml version="1.0"?> <config> <global> <models> <shipmentsave> <class>Company_Shipmentsave_Model</class> </shipmentsave> </models> </global> <adminhtml> <events> <sales_order_shipment_track_save_after> <...
Now that I learned to use Observers two questions came to my attention: 1 - Is it common to use Observer Pattern to notify just one object about changes? 2 - When just one object need to be updated it's better to use an observer or an event? Or there are cases when just one notification is needed that Observers are more recommended? ...
I write a Mozilla Jetpack based add-on that has to run whenever a document is loaded. For "toplevel documents" this mostly works using this code (OserverService = require('observer-service')): this.endDocumentLoadCallback = function (subject, data) { console.log('loaded: '+subject.location); try { server....
I'm not sure if the title is the best way to describe this question. This book - http://apress.com/book/view/9781590599099 - illustrates an implementation of the Unit of Work pattern. It goes a little something like this. class UoW(){ private array $dirty; private array $clean; private array $new; private array $delete; ...
I'm trying to develop an application where in the people will get notified if there is any change in the PartNumber. Its a Spring based application. Following is the code snippet. I've abstracted the storing mechanism here in SaveSubscriptionIF. The actual details of storing and retrieving are in the implementation class of this interfa...
I am having some trouble with implementing my own observer in Java on the Android platform. I have created a class call NetworkPathJni that uses an Observer interface class called NetworkPathJniObserver to notify other objects of changes. Here is the code for NetworkPathJni.java public class NetworkPathJni { NetworkPathJniObserver ...
Guys, Is there a way to setup a callback in ROR that would trigger at a specific time? Lets say I'm running a contest that expries at a certain time. Lets say Monday July 28th at 9:00. I'd like to set up an observer that ran a function at Monday July 28th at 9:00. Does rails have a method to do this? ...
Hi, In my application delegate I have an NSString which can be modified by a class. What I want to do is to have another class observe this NSString and to react whenever this NSString is changed. Does anybody know how I can do this? Best regards, Paul Peelen ...
I'm running into an error when I try to split the dm-observer class into a separate file from my model class. Previously it worked fine if I put it all into a single file. # test_observer.rb require 'dm-observer' class TestObserver include DataMapper::Observer observe Test before :create do # does funky stuff end end ...
I need send an email alert when the price of a product changes. Is it possible do this with ActiveRecord::Observer or do I need use programming logic in the edit form? ...
Okay this is a design question. I, like many, are still learning Objective-C and Cocoa, and am a little rusty to boot. Anyway, here is the question: Assume I have a ViewController class 'A'. Assume I have a "Camera" class 'B', which is a singleton. Assume I have a UILabel class 'C'. The ViewController 'A' has knowledge of the "Camera" ...
I want to implement the observer pattern and I want class X to observe updates in classes A and B. X is derived from the abstract base class XObs which has the update() function taking an enum as parameter of what has happened. The logical problem here is that X needs to know which of A and B sent the update and X cannot determine th...
i would like to add some Products after the Checkout I have an observer and it's listening on 'checkout_onepage_controller_success_action' when i try $this->_getCart()->addProduct($product, $params); and save the cart the success page will be loaded but no new products in the cart. Any idea what's wrong? ...
I have an NSArrayController linked to a Core Data object, set to Auto Rearrange Content and filtered by a predicate. All is well until I try to nullify a relationship and assign another. At that point, my application crashes and I receive the following error: Cannot remove an observer for the key path "career.type" from Object...
Hi Stackoverflow, I was thinking about implementing a logic similar to observer pattern on my website, for implementing hooks. What I am looking for is something similar to this http://stackoverflow.com/questions/42/best-way-to-allow-plugins-for-a-php-application However the code there is too limited, as I cant attach multiple hooks t...
It seems to me that the Observer design pattern as described in GOF is really the same thing as Listeners found in various toolkits. Is there a difference between the concepts, or are Listeners and Observers really the same thing. (I'm not looking for any specific computer language implementation, I just want to understand the differen...
Hi, I want to set up an observer (using Prototype) which will be triggered when any AJAX call (to the server) is being made. ...
Hey there! I'm relatively new to both GWT and java programming (or OOP for that matter), so apologies for the beginner questions/mistakes in advance. I've been trying to create some kind of observer pattern, but the development mode console keeps dropping error messages and sadly, they're far from helpful. So here's what I'm trying to a...
Hi gentlemen, How do we ususaly deal with a vector whose elements are pointers to object? My specific question is the comment at the end of the code supplied below. Thanks. class A { public: virtual int play() = 0 ; }; class B : public A { public: int play() {cout << "play in B " << endl;}; }; class C : public A { public: int...