Questions about problem solving and planning for a solution through software design.

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6
votes
3answers
193 views

System Decoupled in the Wrong Places: Meta-Problem? [closed]

At a meta level, I often find that when I grow a codebase organically, parts of the system that I eventually find need to know about each other (at least through some interface) have been mercilessly ...
0
votes
3answers
109 views

DDD Request Validation Handling

I stuck somewhere that I can't find a solution! There are plenty of validation questions here, but as far as I see, most of them were asking about entity validation. But what about request validation? ...
3
votes
3answers
224 views

Single Responsibility - is this class doing too much?

I'm redesigning one of my programs which performs certain actions on processes of interest (known as "Monitored Processes" in my program). Some actions I always need to do on those processes are: ...
1
vote
1answer
159 views

Design periodic batch notification system

Problem: I am trying to design a system which takes requests from customers in real time and log them in a database. For example - request to purchase an item. The customer then gets a unique ...
9
votes
1answer
299 views

Enum with a lot of boolean properties

I'm currently working on a webapp where we often need to condition some server logic based on the page that is going to be returned to the user. Each page is given a 4-letter page code, and these ...
4
votes
10answers
964 views

Standardized Data Structure Interface

I want to work with a variety of data structures (arrays, singly/doubly linked lists, sorted structures, etc.) on a plug-and-play basis. For example, I want to be able to easily swap in and out the ...
1
vote
2answers
139 views

Parameterization vs subclassing

Example taken from : Agile software development : principles, patterns and practices A new employee is added by the receipt of an AddEmp transaction. This transaction contains the employee's name, ...
3
votes
1answer
73 views

Synchronization of resource that has moved out of requests filter range

I have a RESTful API with corresponding clients. If a client request fetches a set of resources (Events) based on a filter, say events taking place between 2015-04-13 - 2015-04-19. If an event which ...
2
votes
2answers
103 views

How unit test service method that use repository method

For service methods that call repository methods to interact with database how could I unit test these service methods? For example, public function updateSlideshow($data){ // do some logic ...
2
votes
1answer
141 views

Making more than one instance of factory that is supposed to be singleton

However, there are some classes that should have only one instance. Sometimes they are factories, which you can use to create the other objects in the system. If more than one factory ...
2
votes
3answers
178 views

C++ Virtual destructors used only when there are virtual functions

This is from Effective C++ (Meyers): Classes not designed to be base classes or not designed to be used polymorphically should not declare virtual destructors I don't understand why ...
7
votes
1answer
287 views

Best design to create dynamic set of questions(controls ) in silverlight web application?

I have around 15 templates (this will grow) and each template will have around 10-15 questions. Each question can have answers in different format like text box, list box, dropdown, radio button etc. ...
3
votes
2answers
93 views

Is it a bad idea to put externally dependent logic in ORM classes?

Case in point in Entity Framework, but this is a design question which has applicability to any ORM. In the current application we have a couple of ORM data classes which do stuff not directly ...
6
votes
3answers
289 views

Alternative to Anemic domain objects (Simple example provided)

I want to model (TV)Events and Reminders and I’m wondering what’s ‘the best’ way to model this. The requirements are roughly When an Event has no Reminder, a Reminder can be created When an Event ...
26
votes
11answers
3k views

Given a herd of horses, how do I find the average horn length of all unicorns?

The question above is an abstract example of a common problem I encounter in legacy code, or more accurately, problems resulting from previous attempts at solving this problem. I can think of at ...
3
votes
2answers
384 views

Domain Driven Design - designing Aggregate Roots

Imagine you're designing an application for organizing Workshops. Workshop itself is quite complicated - it acts as a state machine with multiple possible states and transitions between them. We're ...
9
votes
2answers
437 views

Interface Segregation Principle: What to do if interfaces have significant overlap?

From Agile Software Development, Principles, Patterns, and Practices: Pearson New International Edition: Sometimes, the methods invoked by different groups of clients will overlap. If the overlap ...
1
vote
1answer
80 views

Personal pages domains architecture

We're looking to add personal pages generator for our users, which is simple enough while all of them are on our domain. We also want to enable them to purchase their own domains through us, and serve ...
25
votes
6answers
3k views

Is there a design pattern to remove the need to check for flags?

I'm going to save some string payload in the database. I have two global configurations: encryption compression These can be enabled or disabled using the configuration in a way that either only ...
9
votes
2answers
220 views

Do we need to validate entire module usage or just arguments of public methods?

I've heard that it is recommended to validate arguments of public methods: Should one check for null if he does not expect null? Should a method validate its parameters? MSDN - CA1062: Validate ...
2
votes
1answer
283 views

Thoughts on having a generic, reusable grid viewmodel

I'm developing a wpf-based application and I'm currently struggling to find the best way of supporting a recurring scenario in it. This app uses grids a lot. There are a bunch of features I want in ...
9
votes
2answers
184 views

Programming to Data Oriented Interfaces

There is a portion of our codebase written in the following style: // IScheduledTask.cs public interface IScheduledTask { string TaskName { get; set; } int TaskPriority { get; set; } ...
4
votes
1answer
76 views

How does an product order payment works during a race condition?

This is a pretty generalized question which I am asking. Scenario 1 I have a product 'Pen' which has a quantity of 1. Now 2 users a and b has come to buy the product.User 'a' clicked on buy now and ...
5
votes
3answers
456 views

How to solve circular dependency?

I have three classes that are circular dependant to each other: TestExecuter execute requests of TestScenario and save a report file using ReportGenerator class. So: TestExecuter depends on ...
2
votes
2answers
514 views

Entity Component System Coupling

Lately I've been working on a small personal project which is basically an Entity Component System framework with autoupdated Systems. While I have a pretty good idea on the way the framework should ...
6
votes
2answers
258 views

Handling interface segregation in C++

I'm designing a "view" handling system for a game. The goal is to be able to have different "views" that can be shown in sequence or stacked on-top of each other. For example, the initial splash ...
18
votes
9answers
1k views

Good design: How much hackyness is acceptable? [duplicate]

Possible Duplicate: Prototyping vs. Clean Code at the early stages I'm right in front of a difficult decision. I have a problem in my codebase (it's in C++), which I could solve in two ...
17
votes
8answers
2k views

Refactoring a long method which is based on large number of switch cases [duplicate]

We are using Java as a backend development language. One year back, we wrote a method which uses switch cases based on Enums values. Since we are continuously adding enum members and according adding ...
-2
votes
1answer
56 views

Getting a button click from a circuit board to display in a table on a PC [closed]

I'm thinking of making a project in my free time whilst I'm away from university. The idea is that I am a swim coach and I want to record swimmer's times over 2 lengths. So I'll click start on my ...
15
votes
6answers
2k views

When is a circular reference to a parent pointer acceptable?

This Stack Overflow question is about a child having reference to its parent, through a pointer. Comments were pretty critical initially of the design being a horrible idea. I understand this is ...
3
votes
3answers
118 views

Deleting a domain object and ensuring any remaining references are subsequently unusable

If I have a domain class with an instance method Delete(). What is the best way to ensure that any leftover references to an instance that has "deleted itself" are subsequently unusable? This ...
6
votes
3answers
156 views

Overriding Equals in an unbrittle way

I have a class WorkflowItemSearchCriteria whose instances represent a set of values and references that will be used to return a filtered result set of workflow items based on the given search ...
21
votes
5answers
1k views

Implementing an interface when you don't need one of the properties

Pretty straight-forward. I'm implementing an interface, but there's one property that is unnecessary for this class and, in fact, shouldn't be used. My initial idea was to just do something like: int ...
12
votes
4answers
901 views

How does having too many instance variables lead to duplicate code?

According to Refactoring to Patterns: When a class is trying to do too much, it often shows up as too many instance variables. When a class has too many instance variables, duplicated code ...
1
vote
2answers
483 views

C# .NET MVVM software architecture and naming conventions

I am currently working on a software using C# .NET and WPF with the MVVM pattern. Though the software is almost done, I have been discussing our architecture for a long time and I would like to get ...
11
votes
4answers
290 views

Is it better to team up with a designer, or to piece out design work to a contractor?

I am clueless when it comes to design but I am proficient in programming. If you are a programmer who lacks visual design skills, what has worked best for you -- to pair up with a graphic designer or ...
0
votes
2answers
126 views

DAO design for writing big XML file on database

I am currently working on JavaEE application (Spring, Hibernate). I have to put a big XML file (more than 1 gigabyte) on a relational database (Postgres). The application does not use batch ...
215
votes
16answers
16k views

Project is nearly done, but procedural spaghetti code. Do I rewrite or just keep trying to ship it? [closed]

I'm a beginner web developer (one year of experience). A couple of weeks after graduating, I got offered a job to build a web application for a company whose owner is not much of a tech guy. He ...
2
votes
1answer
100 views

Pass request as argument to service client vs. pass service client as argument to request [closed]

I need a design recommendation: I have a class that send a http request via another class WebServiceHandler() I am hesitating between the following two implementations, which one to choose?which one ...
4
votes
1answer
129 views

What is the most efficient way to implement a RESTful client app?

I am working on a web application for ranking some products based on some factors. The user send a search query to 5 restful webservices which by their turn send a response in a JSON format and ...
4
votes
1answer
79 views

Mobile app architecture to improve speed and reduce data transfer

Business Context of the Problem Our iphone app allows users to pay merchants and earn rewards. Users can also do things like: View transaction history View their points and available rewards, or ...
2
votes
1answer
70 views

Persistence Strategies - Filling a cache strategy

Let's say I have an interface IDataAccessObject<TSource> with CRUD methods to access a data source. I have an implementation StrategyDataAccessObject<TSource>, which uses an strategy ...
26
votes
2answers
2k views

Is there a named anti pattern for historically grown software? [closed]

Is there an anti pattern that describes a historically grown software system where multiple developers just added new features to the system but no one really kept an eye on the overall architecture ...
1
vote
1answer
69 views

How can I create a client for a service without hiding the parameters needed for each endpoint?

I'm creating a client to a third-party soap web service in my application. Here is the way I'm thinking of doing it: Create a ClientFactory that makes a client based on the wsdl file, and sets ...
4
votes
2answers
1k views

How is intermediate data organized in MapReduce?

From what I understand, each mapper outputs an intermediate file. The intermediate data (data contained in each intermediate file) is then sorted by key. Then, a reducer is assigned a key by the ...
3
votes
1answer
104 views

Does my design break modularity and loose coupling?

I want to know if my implementation is modular and loosely coupled such that pieces can be replaced easily. Any concrete class that extends the abstract class HexGridLayout will be expected to ...
108
votes
17answers
22k views

Is premature optimization really the root of all evil?

A colleague of mine today committed a class called ThreadLocalFormat, which basically moved instances of Java Format classes into a thread local, since they are not thread safe and "relatively ...
2
votes
0answers
31 views

Should my application call statsd directly or should I call statsd based off logs?

I'm planning on incrementing counters in statsd based of various events within my application. I have logging in place for these events. So, from my viewpoint I have two options: Update the ...
0
votes
2answers
192 views

Limiting certain functionality to development environment only [closed]

I intuitively think that an application should be exactly the same in DEV, QA, and PROD environments. However, I have been asked to add a feature to an application that will only be available in DEV ...
4
votes
2answers
633 views

Python classes with only one instance: When to create a (single) class instance and when to work with the class instead?

Given a Python class which will be instantiated only once, i.e. there will be only one object of the class. I was wondering in which cases it makes sense to create a single class instance instead of ...