observer-pattern | 易学教程

Magento event observer for bulk import for products

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问题 Is there any event for "bulk import of products/customers"? I intend to make a module for my vendors to upload their product information in xml/csv through the backend. When they upload, I need to update my Solr records. Thanx 回答1: You can override the Mage_Catalog_Model_Convert_Adapter_Product::saveRow() as: 1> in config.xml <global> <models> ... <catalog> <rewrite>  <convert_adapter_product>MagePsycho_Productimport_Model_Convert

Will observers automatically removed when observers become nil?

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问题 I'm uisng addObserver:selector:name:object: in viewDidLoad . And I'm using removeObserver:name:object: in viewWillDisappear:animated: to remove observer. What will happen if I failed to remove observer by passing wrong parameter to removeObserver:name:object: ? (For example, observer isn't removed if I pass wrong notification to parameter name or wrong object to object or Observer ) If the observer still not nil after calling removeObserver:name:object: , I can find out that removing observer

MVC vs. Observer Pattern

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问题 I've recently asked a question on StackoverFlow about the MVC: Can the MVC Design Pattern / Architectural pattern be used in Desktop Application Development? Based on the answer provided I started research on how this would be implemented in a Windows form Application. I came upon the following CodeProject article: http://www.codeproject.com/KB/cs/model_view_controller.aspx In the comments below the article, certain users argue that (although this is a good article) it is actually the

Observing value changes to an NSUserDefaults key

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问题 I'm interested in the value change of a particular key which I keep in NSUserdefaults. However, what I have is not working for me. observeValueForKeyPath does not get triggered. Update: I think I've discovered the issue. Rather than using a defined constant, if I use a string then it gets fired. [[NSUserDefaults standardUserDefaults] addObserver:self forKeyPath:kSomethingInteresting options:(NSKeyValueObservingOptionNew|NSKeyValueObservingOptionOld) context:nil]; } - (void

Choosing which base class to override method of

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问题 Given the following: class Observer { public: virtual void Observe(Parameter p) = 0; }; template<size_t Tag> class TaggedObserver : public Observer { }; class Thing : public TaggedObserver<0>, TaggedObserver<1> { public: virtual void Observe(Parameter p) override; }; Thing::Observe overrides both TaggedObserver<0>::Observe and TaggedObserver<1>::Observe . Is there a way to provide a different override for each base class? Rationale: I want the class to be able to observe two notification

Knockout's mapping breaks observable arrays

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问题 I'm experiencing a strange problem with Knockout's mapping plug-in. If I fill an observable array through mapping I can't iterate the array or get its length, even though the UI is updated correctly, the array seems empty. You can find a working jsFiddle here: http://jsfiddle.net/VsbsC/ This is the HTML mark-up: <p><input data-bind="click: load" type="button" value="Load" /></p> <p><input data-bind="click: check" type="button" value="Check" /></p> <table> <tbody data-bind="foreach: items">

Continue using subscription after exception

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I was trying out a "type-to-search" Reactive-Extensions sample which takes a string from a textbox (WPF app if it matters) and does a potentially-lengthy server-side search (simulated in my case with a Thread.Sleep) and displays the result(s) in a listbox. The key features of this particular "module" would be : async search; UI is not frozen while searching throttled; typing fast would not generate a server-side search for each keystroke distinct searching; after searching for "asd" and having the result(s) displayed typing fast [backspace], d (i.e. deleting the last character and retyping it

Making a JFrame and Observable Object

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问题 I have a class let's say MyJFrame which represent the GUI of my application. It implements the interface Observer and override the method update . public class MyJFrame extends JFrame implements Observer{ ... public void update(Observable arg0, Object arg1){ ... } } Now I want to make also my JFram an Observable object but I can't because it already extend the class JFrame . I tried to create a variable of type Observable in my class. public class MyJFrame extends JFrame implements Observer{

Problem Implementing Observer Pattern : “Member reference base type ________ is not a structure or union”

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问题 I've been implementing a barebones observer pattern and am stuck on a somewhat cryptic error: "Member reference base type 'Observer *' is not a structure or union". I assume this has something to do with my use of templates, with which I'm still fairly uncomfortable. Here is the offending code (most cons/destructors removed to simplify things): Subject interface: class Subject { public: virtual void notify(); private: list< Observer * > m_observers; }; Subject implementation: void Subject:

How do I know the generic object that the Observer class sends in Java?

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I am implementing the Observer / Observable pattern using Java. However, I am encountering a problem in the Observer portion of my code. Observable public class Model extends Observable { public void notify() { this.setChanged(); this.notifyObservers(new ArrayList<A>()); this.notifyObservers(new ArrayList<B>()); } } Observer public class View implements Observer { @Override public void update(Observable observable, Object object) { // TODO: If object is ArrayList<A>? System.out.println("A"); // TODO: If object is ArrayList<B>? System.out.println("B"); } } How would I fill in the TODO comments