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

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0
votes
3answers
133 views

Storm topology to handle “dating website”-like workloads

suppose im writing a dating website, similar to okcupid. there are profiles, and i need to compute the (N^2) "match" table - given every 2 profiles whats the match between them? I was thinking this ...
-3
votes
1answer
73 views

Class refactoring [on hold]

I have many rows in databases that are in fact classes, eg: 1-2 3-4 .. 10+ Something Now there are 2 options. One is to create class per table row (Something.class etc.), or to create single class ...
2
votes
4answers
223 views

Which design pattern for a single class accessing an object representing a data structure?

Which design pattern should I use when I have a class representing a data structure (aka C-style struct) and I wish to have only a single class to be able to access it. I was thinking of simply ...
1
vote
1answer
114 views

How to optimize the application with huge number of database requests per minute

I have to provide free demo of some service to end users in my application. Free demo could be of 30 mins, 1 hours, 5 hours etc. (predefined time) for a new user for one time only. User can also ...
0
votes
1answer
21 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 ...
1
vote
2answers
88 views

Dependency injection vs dependency lookup in a layered architecture

Given a layered architecture, where the business logic is isolated in a package from all other layers, like persistent storage, user interface, interfaces for various (vendor) remote services, etc, I ...
3
votes
3answers
320 views

Best approach for tracking dependent state

Let's pretend I work on a project tracking application. The application is a database backed, server hosted, web application. In this application there are Projects which have many Activities which ...
1
vote
1answer
36 views

What's the best way to store class/type info in a plugin system in your software?

There are lots of applications like 3ds Max, Maya, etc that allows you to use plugins, where even the default nodes are created as plugins. This is all good but if the developer changes the ...
3
votes
1answer
64 views

Consistent snapshot

Suppose process A has a consitent snapshot of some entities. And it is constantly receiving updates for this enteties. Now client B connecting to A and it should receive the consistent snapshot of ...
-1
votes
1answer
52 views

Pathfinding in a 3d world with obstacles?

What are some methods for pathfinding in a 3d world? Object X needs to move from Point A to Point B but it might have to avoid things like asteroids, planets or gas pockets that makes the object ...
1
vote
1answer
49 views

Rich object model in the context of a good REST API and of an existing rich object model on the server-side

First off, let's frame this question in the context of a good REST API and an existing rich object model on the server-side, as well as modern web architecture (MVC frameworks like angularjs). I'm ...
0
votes
1answer
141 views

Full screen command line app that user cannot close in any way [on hold]

All I'd like user to see is a "full screen" command line interface running my program. Users can enter certain input when prompted to, but they shouldn't be able under any circumstances to stop the ...
3
votes
0answers
95 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 ...
-2
votes
0answers
22 views

Arduino Bluetooth Programming [closed]

I'm part of a group where we need to make a boat that can do several tasks, and I have been put in charge of programming. I have an Arduino, and it has to control a water pump and a motor that will ...
1
vote
1answer
143 views

MongoDB Embedded vs Reference Private info

I have searched extensively for a similar Mongo schema design and can't find relevant examples. I have a store (with public info), each store has an account (with private account info). // store ...
1
vote
2answers
492 views

Is there a better way to organize my module tests that avoids an explosion of new source files?

I've got a neat (so I thought) way of having each of my modules produce a unit-test executable if compiled with the -DTESTMODULE flag. This flag guards a main() function that can access all static ...
2
votes
1answer
86 views

Ambiguity of seemingly clear method names in APIs

(The question is language-agnostic, but to illustrate the point, I wrote the examples in C#.) Say I'm trying to model the behavior of "components" that communicate via "ports". I might model this ...
0
votes
0answers
81 views

Java server side : Is this a good design/layered approach? [on hold]

We are in the process of designing an application using AngularJS, RESTful service (Jersey) and JPA for CRUD operations.The RESTful layer might call other external services to get data. There could be ...
1
vote
1answer
100 views

Does Go implicitly discourage getters and setters and encourage direct member access?

As the title says, is accessing public struct fields more idiomatic in Go than getters and setters? Wouldn't that lead to violation of data encapsulation, also public fields in other OO languages like ...
2
votes
2answers
160 views

Archive Without Adding Dependencies [closed]

We're going back and forth on this problem and I'd like to have oppinions: We have a library calculating stuff and some module with GUI logic using it. We want to add some kind of archiving to the ...
-1
votes
1answer
62 views

How to make variables inherent to an object or system

How can one make variables inherent to an object or system? For example, when creating a web browser, each option that is created for the user to have control over (i.e. how a window opens, if ...
2
votes
3answers
253 views

Repetitive code over multiple classes. Best way to centralize code?

I'm working with 3D arrays that I flatten into a 1D arrays with the following index calculation: index = x + WIDTH * (y + DEPTH * z) I'm starting to notice that I'm using the calculation all over ...
2
votes
1answer
91 views

Is it OK to deprecate methods that need to be public due to the packaging model but are not to be used outside the codebase in Java?

I am currently working on a semi-large project that has several packages. There are 3 main packages, a "client" package, a "server" package and a "common" package. There are two jars, one for the ...
-3
votes
0answers
28 views

Application to generate reports from boiler plate text [closed]

I write long complex reports for a living. Much of the content of these reports could be generated automatically from boiler plate text. I would like to develop a stand-alone application which would ...
0
votes
0answers
330 views

Online stores service design [duplicate]

I am designing an online store service app with rails. Everyone who wants to make his/her own store can do it with this app by just signing up and choosing a domain. I want to make it as SaaS as it ...
7
votes
6answers
463 views

Many small requests vs. few large requests (API Design)

I'm currently working on a project with an organization as follows: Client - Gets data from the main server via REST api. Server - Requests data from various other servers via third-party APIs ...
2
votes
2answers
175 views

Designing entities that should be mutable through the GUI but protected from programmer error

I have a set of entities, for now represented by very simple classes (further simplified for this example): public class Item { public string Name { get; private set; } public double ...
2
votes
2answers
67 views

Creating an auto-patching system for Spring Hibernate Application

I have this question for few months now. We have a web application which has monthly changes and weekly bug fixes if any. Usually we just build the new war, undeploy the old ones and redeploy new ...
4
votes
1answer
201 views

Would SQLite be less useful without accepting inserts of non-numeric values into numeric columns?

In SQLite the following statement would be successful and the string would be inserted/updated into the SALARY column which is of type INTEGER: update employee set salary='TOO MUCH' where emp_id=1; ...
3
votes
2answers
156 views

IoC invalidation

I have a bunch of services that get registered as singletons by my IoC container on startup, all of these services have a constructor which takes in a connection string which is used by the underlying ...
1
vote
1answer
956 views

Erlang chat app design?

I have a chat app made in node/socket.io. Scalability factors have made us choose Erlang/Ejabberd/xmpp and it will replace node/socket. I have a few questions: Currently using MySql for chat ...
6
votes
2answers
227 views

Should HTTP Request/Response objects be immutable?

I think it's safe to say that most web applications are based on the request/response paradigm. PHP has never had a formal abstraction of these objects. One group is trying to change this: ...
-1
votes
1answer
1k views

What is meant by Distributed Systems Coding interview questions [closed]

I was told that I will be asked coding questions in my interview and that the context will be related to Distributed Systems (I took ONE Distributed Systems course and I don't even remember much from ...
5
votes
2answers
366 views

Why should ViewModel route actions to Controller when using the MVCVM pattern?

When reading examples across the Internet (including the MSDN reference) I have found that code examples are all doing the following type of thing: public class FooViewModel : BaseViewModel { ...
1
vote
1answer
46 views

Are Serverlet Containers' Characteristics Against Scalability and Fault-Tolerance of a Web Application?

We most likely deploy a JVM-based Web application (e.g., Scala) on a container (e.g., TOMCAT, Jetty, etc.). Does the following points about a serverlet container goes against us to create a scalable ...
0
votes
2answers
69 views

Content delivery design

I'm designing a system where users can access files stored in an external content storage service such as AWS's S3. Here's a simple diagram: ------ ------------ ----------------- | User ...
4
votes
1answer
105 views

Parking Simulation Software Design

I've been requested to develop a quite well known problem for a job interview. The Parking Simulation which an example can be found here. I came up with some ideas for which design pattern should I ...
3
votes
2answers
645 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
4answers
1k 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 ...
1
vote
3answers
169 views

Avoid opt(options) in javascript [closed]

A lot of frameworks, most like jQuery plugins uses the "optional" parameter. Basically a dictionary (or key/value structure) with a bunch of additional parameters instead of send in the parameter's ...
1
vote
2answers
167 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 ...
3
votes
2answers
65 views

Changing a design later down the track seems time consuming for its value

(For those who don't code, don't be intimidated by the code snippets in this question, they question is about approach to changing a design rather than the code design itself). Recently I put ...
4
votes
1answer
132 views

Should I always throw the most specific or should I try to generalize exception types?

Say you normally have FooException. /** * @throw FooException If Foo is invalid for searching. */ public bool exists(Foo a) But at some point you need to have two more specific exceptions for ...
2
votes
2answers
101 views

Too specific of namespacing/packaging

I'm about to start building a C# library for English and French morphology as a side project. The library will be later merged with other linguistic aspects (phonology, sentence parsing, etc). for ...
3
votes
2answers
104 views

What kind of base for Decorator: interface, abstract class, non-abstract

What should be at the top of inheritance tree of Decorator design pattern? I mean the base for both components and decorators non-abstract class: has data fields, implements methods abstract class: ...
1
vote
1answer
140 views

How to decide if object should request or receive data?

Deciding whether an object should request data (by calling a function) or receive data (by having a function called from another object) is probably dependent on the exact situation. So how do I ...
1
vote
1answer
143 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 ...
3
votes
2answers
255 views

implementing dynamic query handler on historical data

EDIT : Refined question to focus on the core issue Context: I have historical data about property (house) sales collected from various sources in a centralized/cloud data source (assume info ...
1
vote
1answer
92 views

How to evaluate the performance of a Data Access Layer b/w two ORM's?

I am currently working on a project where I am going to replace the Data Access Layer from a custom ORM to Entity Framework.(The product is almost complete and mostly any changes that will follow ...
2
votes
1answer
431 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 ...