Command, callback and observer patterns have different semantics: callback – notifies a single caller that some operation finished with some result observer – notifies zero to n interested parties that some event (for example a finished operation) happened command – encapsulates a operation call in an object thus making it transferable over a wire or … Read more
I don’t have any firsthand experience but judging from the API you can just write your own class that implements the Application.ActivityLifecycleCallbacks interface and register that class on the provided Application class instance getApplicaton().registerActivityLifecycleCallbacks(yourCustomClass); This class will receive the same callbacks as your individual activities. Good luck. PS. This is API level 14 btw, so … Read more
I strongly prefer the first way for several reasons: Representing concepts/functionality via interfaces/class hierarchies makes the code base less generic, flexible, and then more difficult to mantain or scale in the future. That kind of design imposes a set of requirements on the type (the type implementing the required functionality) which makes it difficult to … Read more
You can call Model._save_callbacks to get a list of all callbacks on save. You can then filter it down to what kind you need e.g. :before or :after like this: Model._save_callbacks.select {|cb| cb.kind == :before} Works the same for Model._destroy_callbacks etc.
This is a more general answer for future viewers. Callback types There are a few different types of predefined callbacks: final VoidCallback myVoidCallback = () {}; final ValueGetter<int> myValueGetter = () => 42; final ValueSetter<int> myValueSetter = (value) {}; final ValueChanged<int> myValueSetter = (value) {}; Notes: VoidCallback is an anonymous function that takes no arguments … Read more
Using ‘&?’ returns undefined if the attribute has not been set. ‘&’ = callback function is defined always. ‘&?’ = callback function is defined only when attribute is defined in html template. bindToController: { callback: ‘&?’ }, controller: function() { if (this.callback === undefined) { // attribute “callback” was not defined } } Note: Works … Read more
From the Meteor.call documentation: On the client, if you do not pass a callback and you are not inside a stub, call will return undefined, and you will have no way to get the return value of the method. That is because the client doesn’t have fibers, so there is not actually any way it … Read more
Edit 2014-01-28: New readers, make sure you check out Zac’s answer below. He has a much neater solution that will let you define and instantiate a scoped function in the class definition using the fat arrow syntax. The only thing I will add is that, in regard to option 5 in Zac’s answer, it’s possible … Read more
You can set the on_failure proc in the omniauth initializer in an even cleaner fashion: OmniAuth.config.on_failure = UsersController.action(:oauth_failure)
There is indeed a hint in the docs: callback should complete immediately since otherwise the thread which handles the results will get blocked. The callbacks are handled in the main process, but they’re run in their own separate thread. When you create a Pool it actually creates a few Thread objects internally: class Pool(object): Process … Read more