chaining

问题 I'm new to RxAndroid and trying to chain responses. I'm using this github API to retrieve data. Along with each issue there are comments link and events link associated with it which I want to fetch and update existing object with list of comments and events to form something like this. [ issue: { comments: [ { . . }, { . . } ] events : [ { . . }, { . . } ] ] ] I could retrieve initial response with following code GitHubService gitHubService = ServiceFactory.createServiceFrom(GitHubService

问题 I'm new to RxAndroid and trying to chain responses. I'm using this github API to retrieve data. Along with each issue there are comments link and events link associated with it which I want to fetch and update existing object with list of comments and events to form something like this. [ issue: { comments: [ { . . }, { . . } ] events : [ { . . }, { . . } ] ] ] I could retrieve initial response with following code GitHubService gitHubService = ServiceFactory.createServiceFrom(GitHubService

问题 Is there any merit in promisifying synchronous operations so that by design they can be chained in onSuccess or onError callbacks? Eg: function loadSettings(path) { if (fs.existsSync(path)) { return Q(fsJson.loadSync(path)); } return new Q.defer().reject('No local settings!'); } doingSomethingFirst() .then(loadSettings, obtainSettings) .then(doSomethingWithSettings) .done() What's best? 回答1: No, moreover, it gives the false impression that these methods are async so you or other developers

问题 I would like to perform a query like SELECT * FROM ( SELECT * FROM products ORDER BY price ASC ) AS s GROUP BY item; which return the cheapest of all products for each item. Using this subquery is good because it can run in O(N logN) time. So I can find this with find_by_sql, but it would be nice to be able to chain it with other scopes for Product. Anyone know how to either write this as a scope or chain scoped and find_by_sql? 回答1: You should be able to do something like Product.from("

问题 I consider myself (at best) a mid-level JavaScript guy...and of course...I want to understand HOW some things are accomplished so I can write better code. As such, I've been looking under-the-hood of jQuery trying to uderstand it a little more about how certain things are accomplished. For example: jQuery handles the case where IE and Opera return items by name instead of ID by doing the following: // HANDLE: $("#id") else { var elem = document.getElementById( match[3] ); // Handle the case

问题 Consider a class MyClass with: a member function myClass& myFunction1(int) that modifies the object and returns *this a member function int myFunction2() const that does not modify the object Does the C++11/14 standard guarantee that: myclass.myFunction1(myclass.myFunction2()).myFunction1(myclass.myFunction2()); is equivalent to: myclass.myFunction1(myclass.myFunction2()); myclass.myFunction1(myclass.myFunction2()); 回答1: No. The compiler can first call myclass.myFunction2() twice and then do

问题 In C# how does one implement the ability to chain methods in one's custom classes so one can write something like this: myclass.DoSomething().DosomethingElse(x); etc... Thanks! 回答1: Chaining is a good solution to produce new instance from existing instances: public class MyInt { private readonly int value; public MyInt(int value) { this.value = value; } public MyInt Add(int x) { return new MyInt(this.value + x); } public MyInt Subtract(int x) { return new MyInt(this.value - x); } } Usage:

问题 The output of this program: #include <iostream> class c1 { public: c1& meth1(int* ar) { std::cout << "method 1" << std::endl; *ar = 1; return *this; } void meth2(int ar) { std::cout << "method 2:"<< ar << std::endl; } }; int main() { c1 c; int nu = 0; c.meth1(&nu).meth2(nu); } Is: method 1 method 2:0 Why is nu not 1 when meth2() starts? 回答1: Because evaluation order is unspecified. You are seeing nu in main being evaluated to 0 before even meth1 is called. This is the problem with chaining. I

问题 Today I'm working on a pet project using chained function calls, and I'm curious how I might detect when the last function in the chain is executed. For example: func1('initial data').func2().func3().func4(); And after func2-4 have finished working on 'initial data' I'd like to detect when func4 is done. Since func4() isn't always the last function in the chain, aka it could end at .func3() or .func5() for example, or I could mix my function calls up depending on what I'm trying to do, I'm

问题 I'm trying to understand Promises from the MDN documentation. The first example demonstrates the then and catch methods: // We define what to do when the promise is resolved/fulfilled with the then() call, // and the catch() method defines what to do if the promise is rejected. p1.then( // Log the fulfillment value function(val) { log.insertAdjacentHTML('beforeend', val + ') Promise fulfilled (<small>Async code terminated</small>)<br/>'); }) .catch( // Log the rejection reason function(reason