conceptual

问题 A class TaskGroup mainly contains a list of Task s. I want to collect certain tasks ta1 , ta2 , tb3 , ... from various groups ga , gb , gc , ... and use this list in a display window/class. The choice of tasks for the collection is of no concern for this question. (As the question is rather conceptual than technical, the examples are mostly pseudo code. Since I'm using Qt in this particular case, I'll be using Qt classes, but the question shouldn't be limited to this case.) class Task; class

问题 This is a conceptual question and I haven't been able to find the answer in SO, so here I go: Why instance variables are used to connect controllers and views? Don't we have two different objects of two different classes (Controller vs Views). So, when the view is rendered we are in a different context, but we are using instance variables of another object? Isn't this breaking encapsulation in somehow? How does Rails manage to do that matching from one object to another? Does it clone all the

问题 Stephen Toub blogged that Both SynchronizationContext and TaskScheduler are abstractions that represent a “scheduler”, something that you give some work to, and it determines when and where to run that work. There are many different forms of schedulers. For example, the ThreadPool is a scheduler: you call ThreadPool.QueueUserWorkItem to supply a delegate to run, that delegate gets queued, and one of the ThreadPool’s threads eventually picks up and runs that delegate. Your user interface also

问题 I'm confused. How can one or many Task run in parallel on a single thread? My understanding of parallelism is obviously wrong. Bits of MSDN I can't wrap my head around: The async and await keywords don't cause additional threads to be created. Async methods don't require multithreading because an async method doesn't run on its own thread. The method runs on the current synchronization context and uses time on the thread only when the method is active. .. and: Between starting a task and

问题 In Java, Do objects encapsulate data so that not even other instances of the same class can access the data? Only when the keyword "private" is used? What are "accessor methods" in Java - methods like getName()? Thanks 回答1: I don't tend to think of it in terms of one object having access to another, but rather what code has access to what data within an object. In Java (and C#, btw) code within a class has access to the private members of any object of the same class. Then you've got package

问题 In Java, Do objects encapsulate data so that not even other instances of the same class can access the data? Only when the keyword "private" is used? What are "accessor methods" in Java - methods like getName()? Thanks 回答1: I don't tend to think of it in terms of one object having access to another, but rather what code has access to what data within an object. In Java (and C#, btw) code within a class has access to the private members of any object of the same class. Then you've got package

问题 I was watching wwdc videos this afternoon and I heard the word Bonjour . So I just want to know what is Bonjour in Apple . This is just to clear the concept . Thanks 回答1: In computing, Bonjour (formerly Rendezvous1) is Apple Inc.'s trade name for its implementation of Zeroconf, a service discovery protocol. Bonjour locates devices such as printers, other computers, and the services that those devices offer on a local network using multicast Domain Name System service records . More about

问题 I'm try to design "Network Connection" for easily use to retrieve data from server. However, I facing a design problem. My NetworkUtil Class which I'm going to use was designed as class NetworkUtil public NetworkUtil(URL, resultType); // resultType might be XML or RAW public setListener(listener); // listener will notice when result has arrive public addPostData(key, value); public connect(); // connect start new thread, so result will shown in listener interface NetworkUtilListener1 public

问题 Since I got some negative comments on my system design on this question (concerning the implementation of such system), I hope that if I present the problem I could get some better suggestions. I am trying to design a modular application to be used for feature matching in video frames (e.g. matching on very close frames of a movie or a video, like "the product" in this article by Sivic, Zisserman). The idea is to allow for an easy switch between different feature detection algorithms as well

问题 I want to get the value of an unknown number in equation containing modulus % in Java For example: x % 26 = y if I have the value of y how can I get x 回答1: The problem is that there are either zero solutions (if Math.abs(y) >= 26 ) or an infinite 1 number of values of x that satisfy that equation for a given y . The general answer is: x = 26 * k + y for any integer value of k . You can pick whatever k you want. 2 1 In practice, the range will be limited by the range of integer values you are