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

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3
votes
2answers
843 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 ...
1
vote
0answers
39 views

If the externally callable interface of a class is called its API, what is “what can be overridden” called?

It's about what the class gives access to through inheritance. It has a three letter abbreviation but not API. I've seen this before but can't remember at the moment. The term is usually used in ...
1
vote
4answers
2k views

iOS chat application design, sending/relaying the message over to the end user

I have a design question. Let us say you were tasked with building a chat application, specifically for iOS (iOS Chat Application). For simplicity let us say you can only chat with one person at a ...
0
votes
3answers
53 views

Sacrifice server validation in pos of performance with Rich Client validation?

I recently started to work in a java enterprise project (~200 people) that uses a SWT rich client. In many cases I've found business rules not being validated in server side, because the widgets that ...
1
vote
1answer
29 views

Database + Java Design for a scenario

Overview A central web application to supports other web applications(A) for user and its role/permission management. Applications (A) call the central application via API to get the user ...
0
votes
1answer
17 views

Availability on updating, migration, etc

When you want to update, migrate or deploy-new-version of a large and/or critical system, absolutely, you can't shutdown the system and do your job, then start it!!! I want to know what's the ...
1
vote
2answers
221 views

Best approach for a server configuration data collection and reporting solution from a legacy script?

I have a project which involves collecting config data from windows servers in our (very large) server estate. My manager wants me to collect over 150 data items across all configuration areas ...
1
vote
1answer
44 views

How “close” should a IO class/logic be to a form or thread that controls the IO device?

I am having a difficult time determining where my IO logic should reside within my application. In this application there are multiple IO devices both USB and serial. I currently have the idea to ...
1
vote
3answers
107 views

Help me design this use case

I have following entities: Data: User_id Categories: Interests, Disinterests, Categories A, B C... Each categories have sub categories: Interests=Gaming, Physics, Programming etc.. Now each user ...
80
votes
14answers
11k views

How to stop thinking in terms of code? [on hold]

I am a C++ developer at a fairly large organization which has a huge codebase. During the last 6 months since I joined, my mentor has always told me this every time we met for design reviews or ...
1
vote
1answer
69 views

How to handle design changes for auto_ptr deprecation in C++11?

We are testing a library under C++11 (i.e., -std=c++11). The library uses auto_ptr and this pattern: Foo* GetFoo() { autoptr<Foo> ptr(new Foo); // Initialize Foo ...
0
votes
1answer
90 views

Is service layer obligatory? [on hold]

I am going to implement not big web application and it seems that there are not (or almost not) any business logic in it. Only CRUD operations + some filters + security. So the question is -Is it ok ...
4
votes
3answers
245 views

How can I add properties to subclasses and access them without casting from a superclass?

I'm trying to model a multi-dimensional point class in C#. I have about eight different types of points, and there may be more in the future. Right now, I have a superclass (PointBase) that holds all ...
2
votes
2answers
93 views

Depend in the direction of stability: How do I know what is more stable?

According to the Stable Dependencies Principle, the dependency should be in the direction of the stability But: if you don't know what types of changes are likely, it is best to wait and see ...
1
vote
3answers
57 views

How to reuse domain model logic in services?

I am trying to avoid anemic domain models as it's said to be an anti-pattern. But doing so leaves my services to duplicate some of the logic. class User { public $status; public function ...
2
votes
1answer
78 views

Integration between services in a SOA

Assume we have a Bounded Context for Inventory (InventoryBC) and another one for Shipments (ShipmentsBC). These 2 BCs need to communicate together. They are hosted on 2 different services on different ...
4
votes
1answer
558 views

Capturing mobile device system (output) audio

I'm trying to figure out a way to capture the system audio of an Android and/or Windows Phone. The idea is to provide a stream based on the music I'm currently playing on my phone. What I'm not sure ...
2
votes
3answers
610 views

can you have too many dto/bo - mapping method

I have a windows service, 2 web services and a web interface that need to follow the same path (data wise). So I came up with two ways of creating my solution. My concern is the fact that the ...
2
votes
1answer
69 views

Define an object with the interface as a type instead of class name [duplicate]

I try to practice with the design patterns and explore one of the possible implementations of the Observer Design Pattern in Java. I paid attention, that in this example the object is defined with the ...
0
votes
0answers
14 views

Integrating legacy application with new functionality

We have a legacy application with, among other things, the ability to create instances classes within VB6 DLLs dynamically and call methods with varying signatures. We have no way of accessing the ...
1
vote
2answers
162 views

Strategy for Website Talking to API on Same Server

I have a RESTful API that allows retrieval of data through requests such as GET http://example.com/users/id/1 (Coded following this tutorial). The code igniter controller looks like this: class ...
9
votes
9answers
3k views

Why don't RDBMSes return joined tables in a nested format?

For example, say I want to fetch a User and all of his phone numbers and email addresses. The phone numbers and emails are stored in separate tables, One user to many phones/emails. I can do this ...
2
votes
2answers
94 views

Final steps of wrapping up a Python script into a program

I finished building a Python script containing eight functions which download files, extracts them, manipulate and analyze their data and then produce graphs and export them into PNG files. The ...
3
votes
3answers
319 views

Object creation: when should I expose a factory vs wrapping class?

I am having some problems trying to figure out when to use a factory or to wrapper class. This question is slightly geared towards C# I guess, so I'm not sure if this is the correct place to ask. Say ...
8
votes
1answer
531 views

Maintaining separation of concerns

I'm making my first C# app and I am having a bit of difficulty with separation of concerns. I understand the concept, but I don't know if I'm doing it right. I have this as a quick example to ...
0
votes
1answer
55 views

What is the best way to organize RESTful endpoints [closed]

Let's say I have two types of resources I want in my API: person and class. These two have a many-to-many relationship. As such, would I expect to be able to interact with the following endpoints: ...
0
votes
3answers
320 views

i++ vs i+=1 in cycles, why evaluate? [closed]

Why do most programmers use i++ in cycles? Doesn't it mean evaluate and increment. I find more logical to use just an increment i+=1, because that's all I want. WriteLn(i++); would evaluate i and ...
2
votes
2answers
200 views

private method that uses no instance members - better static? [duplicate]

I have a private helper method that uses no instance variables or methods, I feel it would be less confusing if it was static (this way, it's given fewer points it can access). I am a bit unsure if ...
1
vote
1answer
108 views

What is an Application Core? [closed]

I have read Patterns For Large-Scale JavaScript Application Architecture by Addy Osmani, and I was suddenly hit by a question about an application core. What is an application core? What makes it? ...
1
vote
1answer
104 views

Best architecure approach to develop iOS app

I'm trying to create a calendar app similar to this design: Calendar Design I'm currently using this calendar framework: CVCalendar and it's working great, but my question is, what do you think is ...
1
vote
1answer
546 views

MVC URL structure with URI parameters

When creating routes for your MVC web application I have seen two possible ways to pass variables to a controller method: With the first approach the variable is passed to a parameter of the ...
4
votes
3answers
227 views

Fine grained search over a large dataset

I have roughly 4 million records per day and have to keep 7 years worth online, so we are looking at 10.2 billion records that I need to be able to search through. The users are expecting that the ...
0
votes
1answer
49 views

Multiple different versions of similar apps in one project

I need some help to improve the architecture of a site I've built. What I want to achieve within a single Django project is the following: I want a site that comes in several versions (one per ...
1
vote
2answers
83 views

Efficient way to handle foreign keys

I am building a script that checks a large network of sites for invalid links. The idea is to flag links that continuously show as not available so that they can be cleaned by the administration team. ...
2
votes
3answers
130 views

Performing data operations that involve separate applications and data sources

I'm designing an enterprise application that produces output based on some input data from another application. In this case, I happen to have also built and thus do control the source application ...
1
vote
1answer
32 views

How to model table and column objects and their relation

I'm working on a small application where I need to model tables and columns from a relational DB. I've been reading some material on nested classes, which is recommended to be used sparsely. However ...
3
votes
3answers
125 views

Returning a Flag Indicating Success

Whenever I'm writing code, I always stub out my methods like this (not necessarily using generics): public T MyMethod() { T result = default(T); // or null return result; } This always ...
7
votes
1answer
136 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 ...
4
votes
4answers
119 views

Instantiating class that contains methods to check some of the settings and also return values from my app.config file

I am writing a console application and have a class called ApplicationConfiguration that contains methods to check some of the settings and also return values from my app.config file. For instance ...
1
vote
1answer
90 views

Database Design: Rules for students and student groups

I am new to databases. I am using MySql. What I have is a student system which stores rules for students in a school. Each student may or may not be a part of a group (Soccer, Guitar, etc). ...
8
votes
5answers
1k views

Best-practice to manage concurrency into a basket in a e-commerce website

What is the best practice to manage the case where two customers add in the same time a product whose the stock was only 1 ? Must there be a check in the code of the basket to avoid one of these 2 ...
0
votes
0answers
34 views

Design for local text storage (70 000 words) in iOS

I would like to code an interactive story app for iOS devices. There will be a large amount of words locally stored.(70 000, 35 000 for each language as the text will be available in two languages). ...
0
votes
1answer
90 views

Moving methods to a MasterClass so it can be overridden, is there a better way?

I'm looking at a very large object within the application I'm working on, which is there to basically hold all the data together at a large level. Recently, we have started moving some methods out of ...
12
votes
9answers
651 views

Inheritance gone wrong

I have some code where a good inheritance model has gone downhill and I am trying to understand why and how to fix it. Basically, imagine you have a Zoo hierarchy with: class Animal class Parrot : ...
1
vote
1answer
45 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
3answers
106 views

Unit testing text output

I have recently become responsible for a legacy tool that analyses code and provides a log as output. As part of the JUnit suite for this, there are ~100 tests that rely on successfully matching the ...
0
votes
2answers
122 views

Testable design in Swift

I've been searching for so long about how to design testable classes in Swift but every information site just describe basic stuff like how to test, how to assert, why is testing good... My current ...
0
votes
2answers
48 views

Built-in the separate thread execution inside of the method or wrap the method by the thread

Let assume, I have some resource and time-consuming code, which I want to arrange as a separate method. In order to optimize the performance, this code should be executed in the separate thread. Now ...
25
votes
6answers
30k views

Difference between a service class and a Helper class [closed]

I would like to know what differentiates a Service class from a utility class or a helper class? A class only with underlying methods calls the dao's is a service? Doesn't the usage of Helper ...
0
votes
0answers
26 views

Event-handling in WinForms MVC-Implementation

I am trying to implement sort of an MVC-Pattern (Passive View) for a winforms-application to clean up the code. The basics are quite clear and I did implement some views of the application in ...