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

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0
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1answer
37 views

Include system timer in use case diagram

Here in my use case diagram, an sms will be sent to a referenced person by the applicant automatically by the system when an applicant fills up and submits a form. Here as the SMS sending is ...
1
vote
2answers
85 views

Class design for JSON serialization

I've been stuck for some time on a circular reference issue with JSON serialization. I have a card game that I'm pickling to a redis store. As I retrieve the Game state from redis I'm trying to ...
1
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3answers
54 views

Representing a “Belongs to” relationship in an API endpoint

Consider the following pseudo code models: class Post int Id string Title int CategoryId Category Category class Category int Id string Name Note that Post belongs to ...
-1
votes
1answer
85 views

Are there any problems with implementing deleted usernames this way? [closed]

I have a requirement to implement usernames for an application for login purposes. The requirement specifies that the registry associated with the user/username in the database must not be deleted. ...
2
votes
2answers
71 views

Optional Member Data

I am creating a strong binding of an XML specification and I am essentially trying to "flatten" the specification as much as possible, so that it won't feel like you are manipulating an XML tree. ...
4
votes
4answers
202 views

Filling the gap between Conception and Unit Test

I am stuck trying to do TDD. I'd rather seek the counsel of others who have gone before rather than waste time with trial and error. QUESTION: What diagrams / exercises / development processes can ...
6
votes
4answers
185 views

Best way to analyse a large class before refactoring it into smaller classes?

Foreword I'm not looking for a way to refactor a large spaghetti code class, that topic has been covered in other questions. Question I'm looking for techniques to begin to understand a class file ...
7
votes
2answers
237 views

Java System class implementation

The Java System class contains various data members and methods that make perfect sense being there. For instance: System.in (variable) System.err (variable) System.out (variable) System.exit(int) ...
5
votes
4answers
253 views

Two Database Architecture : Operational and Historical

I thought about an uncommon database structure and wonder if anyone has seen it in use before. It's basically using 2 databases: First database hold only the data that is currently valid Second ...
0
votes
2answers
161 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 ...
2
votes
2answers
76 views

How do you maintain protocol of function return value in dynamic language?

In dynamic programming language like Python, Javascript, it's very easy to make a function return an object: def make_vector2(a, b): return {"x": a, "y": b} The 'signature' of the returned ...
1
vote
3answers
292 views

Use interface or abstract class?

Now the title might seem like the question has been asked before but let me explain my situation and you'll see why I am asking this question. Let's consider this interface : public interface ...
0
votes
1answer
64 views

How to create good positive and negative images for opencv to distinguish smiling from not smiling? [closed]

My goal is to create an opencv haar classifier xml that distinguishes between me smiling and not smiling. I created images, cut them, showing me smiling and as negatives not smiling. About 5000 ...
4
votes
2answers
267 views

What is the correct approach for creating an application around a library?

I have a library that defines messages. In my particular instance, it's autogenerated code from an XSD using JAXB (Java). The messages can be very complex, with some members as objects and those ...
-1
votes
1answer
27 views

Extracting client specific code. refactoring possibilities required

I am facing a Design problem. I have a set of classes which writes data in XML,JSON or HTML formates for different clients. I have a class which receives Data and a XML, JSON or HTML writer as it ...
1
vote
1answer
168 views

Is SICP still relevant? [closed]

Today, I came across this book entitled:The Structure and Interpretation of Computer Programs I read the Table Of Contents and it really interests, me. It seems to be exactly what I've been looking ...
2
votes
2answers
210 views

Don't repeat yourself vs do only one thing in a method

I am currently writing some test cases in python. I often end up calling the same two or three lines of code at the start of a test case in order to get the program I am testing going. For example: ...
4
votes
4answers
263 views

Why use an enum to determine node type in a parse tree?

The Sun Compiler Tree API uses an interface called Tree as the parent of all the different kinds of parse tree nodes (assignments, if-statements, class declarations, etc.). A part of this interface is ...
0
votes
1answer
101 views

2 Classes that share similar behaviours but unrelated.

I'm working on something at the moment and am a little confused. I'm working on an enquiry system in PHP (it's Opencart Based, so MVC). An enquiry comes in and depending on what form it was ...
1
vote
2answers
78 views

Building CMS from components

I have a design decision problem and would like to have some thoughts on it. I'm building a CMS to use for my projects and want to incorporate existing components in it, like Doctrine, Monolog and ...
1
vote
2answers
143 views

Implementing an anti-corruption layer with domain logic

I'm building an application that compiles a single PDF document from multiple source PDF documents as follows: it takes the first page of each source document, stamps certain information on top of ...
0
votes
2answers
125 views

Object oriented Classes and single responsibility [duplicate]

I'm reading a book that explain that it is a good thing that classes have a single responsibility, that is, that they do a single thing. I can understand how to implement this in some cases I ...
5
votes
5answers
312 views

Should the method describe its side effects? [duplicate]

I was reading Clean Code by Bob Martin and there's one particular code smell, related to naming, that looks interesting to me: N7: Names Should Describe Side-Effects Names should describe ...
14
votes
5answers
2k views

If Else - Repeated Code Logic

My boss gave me a project with a particular logic. I have to develop a web page which has to lead the navigator through many cases until he/she arrives at the product. This is the path scheme of the ...
1
vote
1answer
91 views

Running an algorithm against a large dataset

We have a python application which does a DFS search against data in a database. Right now, that data is small so I can hold everything in a python container but the data is going to grow and there ...
1
vote
1answer
124 views

Does Separation of Concerns applies to GUI components?

In an application I developed with C#, I use a webbrowser control, it should navigate to some websites, then I would like to extract some contents from the webpages. I do it by manipulation of DOM and ...
0
votes
0answers
35 views

python: area mapping using trigonometric circle

I have a car controlled by a raspberry pi, I would like to create maps to each place it visits. The solution I came up with is simple. Lets say you tell the car to go forward and then after 5 minutes ...
-1
votes
3answers
138 views

What do design and implementation mean?

The words "design" and "implementation" have been used widely. But I am not sure that I understand them. What do design and implementation of a computer-related system (e.g. a computer system, an ...
1
vote
3answers
240 views

Should code comments explain the control flow?

Should comments explain how the application control flow works? For example, the relationships between classes, how this function is used by other functions, and what we are trying to do with these ...
5
votes
2answers
192 views

How to organize predefined queries with Entity Framework?

I have some queries that I use all the time (like get rows only of some specific type, or count something etc.). I'd like to organize them somehow (better then I currently do). Currently I have them ...
3
votes
2answers
135 views

Design, how to utilize The Hardware (multiple threads and/or GPU) while indexing (via a database) a very large set of binary files

Problem How can design my file parser to maximize the hardware when processing (creating meta data for) a large file (i.e. how to avoid being blocked by IO and running out of memory) preferably ...
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 ...
2
votes
5answers
300 views

Why use a bool over more domain specific abstractions

Booleans are often used to model domain specific dichotomies. The most common example I can think of is the success or failure of an operation. It seems to me that a boolean must be interpreted in the ...
3
votes
1answer
116 views

Nested REST urls and parent id, which is better design?

Okay, we have two resources: Album and Song. Here is API: GET,POST /albums GET,POST /albums/:albumId GET,POST /albums/:albumId/songs GET,POST /albums/:albumId/songs/:songId We know that we hate ...
4
votes
4answers
384 views

What architecture/design to adopt when consuming a RESTful API? (iOS App)

TL;DR Part 1) I want to refactor the biggest part of the app on which I work - and it is pretty much spaghetti. It's a single class that makes the requests to the server, parses the JSON and saves ...
0
votes
2answers
51 views

What are some ways to get application settings from users into class objects that also follow proper design principles? [closed]

I'm really confused how to enable the user to apply application settings for an application they are using (that get consumed by to a class object) AND the method I need to use to get the settings ...
4
votes
3answers
87 views

Sets of pair parameters

I have the following class, this class like many rely one parameters coming in as a pair. Originally for convenience, I set them as params Object[] values and check if there is an even number of them ...
0
votes
0answers
29 views

Product Development Design - Customer specific changes [duplicate]

We are developing a web based product that will require customization for various customers. Customers tend to have different rules and nomenclatures, hence the customization requirement. The ...
1
vote
4answers
242 views

How to make one test depend on the results of another test?

Let's say there is a utility class that provides some common static methods used everywhere in your code by many other classes. How would you design your unit tests for the consumers of the utility ...
1
vote
1answer
152 views

Problems with OO design for application with pluggable components

I'm trying to refactor an ugly code and make it easly extendable in the future. The application should be nothing else but a series of components that have input(s) and output(s). The components ...
25
votes
6answers
3k views

When NOT to apply Dependency Inversion?

I am currently trying to figure out SOLID. So Dependency inversion means that any two classes should communicate via interfaces, not directly. E.g. if class A has a method, that expects a pointer to ...
1
vote
0answers
56 views

Should all public API POCO value-type properties be nullables?

I use nullable value types a lot when designing classes that have properties which may remain null, i.e. when the object is being persisted. For example: public int? MyProperty { get; set; } My ...
0
votes
2answers
108 views

Should a “secret access code” use the same security as a normal password? [closed]

Obviously, when you store a password, you should use something similar to bcrypt before you store it in in the database. But I have a client who wants to add the ability to add a "secret code" to ...
7
votes
6answers
475 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
92 views

Free Standing Functions in Global Namespace

When writing non-member, free functions, can they be placed in the global namespace so long as the signature specifies a namespace-scoped object? For example, in the code below, is "Example 2" ...
30
votes
10answers
6k views

Is it reasonable to assume that any physical quantity can be represented by a 64-bit integer without overflow or underflow?

The original binary search algorithm in the JDK used 32-bit integers and had an overflow bug if (low + high) > INT_MAX ...
1
vote
2answers
110 views

Caveats of using String.hashCode() on a switch on java < 1.7

There are several cases when I want to switch over a String input. I decided for implementing something like: public Object doStuff(String param) { switch (param.hashCode()) { case 1234546: ...
2
votes
5answers
271 views

Is it bad or good to wrap mutable objects in immutable containers?

If I have parts of code that need to mutate the underlying data structure but then others that consume, not mutate the structure, is it good practice to create a wrapper which does not expose mutation ...
1
vote
2answers
95 views

How is a dictionary better than a big switch, when mapping data to action? [duplicate]

Often times we see stuff like that in code: void myFunction(string someValue) { if (someValue == "a") { // ... } else if (someValue == "b") { // ... } else if (someValue == ...
0
votes
1answer
45 views

Separate Drawable objects and their Data

I am looking for a way to design my application. Suppose you had a car drawing thing. Car has multiple parts.Some are going to be visible some are not.For example battery should be drawn. So someone ...