observer-pattern

My NSMutableDictionary contains simple keys (@"one", @"two", @"three") and complex keys (@"com.alpha", @"com.beta"). Is it possible to use observers for a complex key? Observers work well with simple keys, but didn't worked with complex keys. What is a solution? [self.dict addObserver:self forKeyPath:@"com.alpha" options:NSKeyValueObservingOptionOld | NSKeyValueObservingOptionNew context:nil]; -(IBAction) onChange:(id)sender { [self.dict setObject:@"newValue" forKey:@"com.alpha"]; } -(void) observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:

I'm building an application which contains a GUI and a Model. I'm using the Observer pattern (using java's built in interfaces) to update the GUI when fields in the model are changed. This is generally working fine, but I have a situation in which a particular String variable in the model (specifically the url of a file) can be changed by two separate JTextFields (swing) the contents of which actually reflects the value of the model variable in question. The issue I am having comes from the fact that an change in one of these JTextFields needs to cause an update to the state of the model, and

Say I have a factory method that churns out instances of type T, and I want an Rx observable sequence for events fired from all my instances originating out of the factory method. Is using Merge() as I have done below the correct and optimal way to achieve this? The other way I did this was to use a static event and make the observable sequence out of that, however I generally don't like using static events and am curious what any Rx experts think would be optimal in this situation? public T MakeFoo<T>() where T: Foo, new() { this.instanceOfObservable.Merge(new T()); return self; } public

There seems to be various ways to implement RecyclerView lists, some more logical than others. Going beyond a simple list to one where the data changes increases the complexity. Additional complexity comes from implementing the ability to view the details of the list items. Although I have had some success at implementing lists in this manner, I feel that what I've come-up with is not efficient and not what was intended when the framework was designed. Looking at the various methods I've used, I keep saying "this can't be the way they want me to do it". The basic application I wish to examine

I am currently using rails 3.0.7 and ruby 1.9.2 and making a rails App which contains a video being loaded from a database while being rendered by FlowPlayer. and a set of slides based on the video. Now, I wanted to synchronize the slides with the video. For the timings, I am asking the user to enter the timings of each slide. So, I was wondering if i could use observer pattern for this by making a sort of central time as the subject and the video and slides as the observers? While, the concept seems correct after going through a number of tutorials on the net, I am not able to proceed or ge

Recently I got into implementing a message dispatching system that uses the "Observer pattern": nothing special here. As I developed it I thought it would be nice to send "Message" objects from the "subject" that could be fundamentally different from each other and could be read from the many "observers". These different messages took the form of different message classes (for example, think about the "User Logout message", "Screen mode toogle" and "Volume level changed", all of these need different information) and soon I found that the "observers" needed not to know about every different

I have been trying to no avail to get the observer pattern working in a relatively simple application. I have 4 GUI classes StarterClass (contains a CompositeWordLists and a CompositeWordListData ) CompositeWordLists (contains many CompositeListItem /s and a CompositeWordListData ) CompositeListItem CompositeWordListData (Contains a DialogWordData ) DialogWordData Here is my Observable interface Observable<T> { void addObserver(T o); void removeObserver(T o); void removeAllObservers(); void notifyObservers(); } And I am creating Observers like this: public class Observers { private Observers()