design-patterns

问题 So in the Data transfer Object there should be only setters and getters.. However what about handling also inserting and deleting objects from the Data transfer Object? public class dto{ setters and getters... .. .. public void delete(){ CustomreDao.delete(this.ID); } } Would it be against the DAO pattern itself? Thanks in advance. 回答1: Ask yourself this: "how hard would it be to update the DAO's delete method?" If you have a lot of DTOs and suddenly need to change the DAO, then that's a lot

问题 I have 3 classes, Account , CappedAccount , UserAccount , CappedAccount , and UserAccount both extend Account . Account contains the following: abstract class Account { ... /** * Attempts to add money to account. */ public void add(double amount) { balance += amount; } } CappedAccount overrides this behavior: public class CappedAccount extends Account { ... @Override public void add(double amount) { if (balance + amount > cap) { // New Precondition return; } balance += amount; } } UserAccount

问题 Wrote a library that, depending on the input data; creates classes and uses them inside a main class. To make the code more maintainable and readable, I've moved the class generation logic into a separate file that exports a factory function. Code was written in ES2015. Now I'm migrating to TypeScript. Here is a pseudo example: factory.ts export default function (foo:string) => { class A { value:string = foo + '-A'; } return { A }; }; Main.ts import factory from './factory'; export default

问题 Wrote a library that, depending on the input data; creates classes and uses them inside a main class. To make the code more maintainable and readable, I've moved the class generation logic into a separate file that exports a factory function. Code was written in ES2015. Now I'm migrating to TypeScript. Here is a pseudo example: factory.ts export default function (foo:string) => { class A { value:string = foo + '-A'; } return { A }; }; Main.ts import factory from './factory'; export default

问题 I have asked another question, which was closed as Too Broad. Now, I will try to specify. Again, I would like to simulate a 1-dimensional point process in R. So far, I've only been working on 2-dimensional simulations and would need a bit of help. My goal is a simulation like in the picture But, I only need the real line with the random points on it. I use spatstat and have already found out that I can generate random points on a 1-dim Line with: rpoisppOnLines(lambda, L, lmax = NULL, ...,

问题 I am currently facing a problem for which I am pretty sure there is an official name, but I don't know what to search the web for. I hope that if I describe the problem and the solution I have in mind, somebody is able to tell me the name of the design pattern (if there is one that matches what I am going to describe). Basically, what I want to have is a job queue: I have multiple clients that create jobs (publishers), and a number of workers that process these jobs (consumers). Now I want to

问题 A developer at work recently started using a class pattern instead of enums in places where enums would usually fit. Instead, he uses something similar to that below: internal class Suit { public static readonly Suit Hearts = new Suit(); public static readonly Suit Diamonds = new Suit(); public static readonly Suit Spades = new Suit(); public static readonly Suit Clubs = new Suit(); public static readonly Suit Joker = new Suit(); private static Suit() { } public static bool IsMatch(Suit lhs,

问题 A developer at work recently started using a class pattern instead of enums in places where enums would usually fit. Instead, he uses something similar to that below: internal class Suit { public static readonly Suit Hearts = new Suit(); public static readonly Suit Diamonds = new Suit(); public static readonly Suit Spades = new Suit(); public static readonly Suit Clubs = new Suit(); public static readonly Suit Joker = new Suit(); private static Suit() { } public static bool IsMatch(Suit lhs,

问题 Basic pubsub architecture question. At a high level, when designing pubsub, I sometimes face a choice between two architectures: Publish mutations or "new-state". Some DB state is mutated, and publishers notify of that change via pubsub. But they include enough information in the message so that the subscriber doesn't need to do a look-up on the DB. Imagine the subscriber has a cache of the DB. It could receive the mutations or new-state, and update its cache without doing a look-up.

问题 Original promise based code I'm trying to rewrite: parentPromise .then((parentResult) => { childPromise1 .then(child1Result => child1Handler(parentResult, child1Result)); childPromise2 .then(child1Result => child2Handler(parentResult, child2Result)); childPromise3 .then(child1Result => child3Handler(parentResult, child3Result)); }); I'm trying to figure a way how to avoid the nested subscriptions anti-pattern in the following scenario: parent$ .pipe(takeUntil(onDestroy$)) .subscribe(