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Questions tagged [design]

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

42
votes
12answers
11k views

Dealing with bad/incomplete/unclear specifications? [duplicate]

I'm working on a project where our dev team gets the specifications from the business part of the company. Both the business management and the IT management require estimates and deadline projections,...
53
votes
12answers
5k views

Develop fast and buggy, then correct errors or be slow, careful for each line of code? [duplicate]

Possible Duplicates: Frankly, do you prefer Cowboy coding? Prototyping vs. Clean Code at the early stages Good design: How much hackyness is acceptable? Does craftsmanship pay off? Which is ...
104
votes
10answers
16k views

Are design patterns really essential nowadays?

I was reading "Coders at Work" and have faced the fact that some of the professionals interviewed in the book are not so enthusiastic about design patterns. I think that there are 2 main reasons for ...
128
votes
10answers
16k views

Is this a violation of the Liskov Substitution Principle?

Say we have a list of Task entities, and a ProjectTask sub type. Tasks can be closed at any time, except ProjectTasks which cannot be closed once they have a status of Started. The UI should ensure ...
197
votes
17answers
51k 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 ...
69
votes
7answers
73k views

When to use abstract classes instead of interfaces with extension methods in C#?

"Abstract class" and "interface" are similar concepts, with interface being the more abstract of the two. One differentiating factor is that abstract classes provide method implementations for derived ...
55
votes
12answers
28k views

Is catching general exceptions really a bad thing?

I typically agree with most code analysis warnings, and I try to adhere to them. However, I'm having a harder time with this one: CA1031: Do not catch general exception types I understand the ...
35
votes
9answers
3k views

Design for future changes or solve the problem at hand [closed]

While writing the code or during design do you try to generalize the problem at the first instance itself or try to solve that very specific problem. I am asking this because trying to generalize the ...
160
votes
16answers
86k views

Is it wrong to use a boolean parameter to determine behavior?

I have seen a practice from time to time that "feels" wrong, but I can't quite articulate what is wrong about it. Or maybe it's just my prejudice. Here goes: A developer defines a method with a ...
77
votes
7answers
23k views

Should I use Dependency Injection or static factories?

When designing a system I am often faced with the problem of having a bunch of modules (logging, database acces, etc) being used by the other modules. The question is, how do I go about providing ...
21
votes
6answers
19k views

Understanding “programming to an interface”

I have come across the term "programming to an interface instead of an implementation" a lot, and I think I kind of understand what it means. But I want to make sure I understand it's benefits and it'...
107
votes
14answers
62k views

What is the ideal length of a method for you? [closed]

In object-oriented programming, there is of course no exact rule on the maximum length of a method , but I still found these two quotes somewhat contradicting each other, so I would like to hear what ...
17
votes
5answers
14k views

What to plan before starting development on a project? [closed]

Say I've received the specifications for a project from a client, and now its time to start developing it. Normally, I just start with the first module (usually user registration) and then go from one ...
6
votes
1answer
893 views

Derive from a base class but not include a condition in the base class's method

The current code looks like this: public class Details { Public void Populate() { WriteChapterDetails(); } public void WriteChapterDetails() { if ( ...
62
votes
11answers
5k views

Clarify the Single Responsibility Principle

The Single Responsibility Principle states that a class should do one and only one thing. Some cases are pretty clear cut. Others, though, are difficult because what looks like "one thing" when ...
49
votes
9answers
13k views

Code Smell: Inheritance Abuse [duplicate]

It's been generally accepted in the OO community that one should "favor composition over inheritance". On the other hand, inheritance does provide both polymorphism and a straightforward, terse way of ...
15
votes
6answers
8k 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 ...
22
votes
4answers
3k views

Legitimate “real work” in a constructor?

I am working on a design, but keep hitting a roadblock. I have a particular class (ModelDef) that is essentially the owner of a complex node tree built by parsing an XML schema (think DOM). I want to ...
26
votes
8answers
4k views

When do you rebuild an application or keep on fixing the existing one [duplicate]

Possible Duplicates: When is a BIG Rewrite the answer? Have you ever been involved in a BIG Rewrite? I am at a customer where I have been tasked to fix a number of issues they have in their ...
13
votes
1answer
3k views

Is wrapping a third party code the only solution to unit test its consumers?

I'm doing unit testing and in one of my classes I need to send a mail from one of the methods, so using constructor injection I inject an instance of Zend_Mail class which is in Zend framework. Now ...
33
votes
6answers
57k views

Pros and Cons of holding all the business logic in stored procedures in web application [duplicate]

In some organization I worked for web applications are developed basing all the business logic in Database stored procedures. For example, use html for view and servlet as controllers to divert the ...
23
votes
8answers
797 views

How does one decide if a data object type should be designed to be immutable?

I love the immutable "pattern" because of its strengths, and in the past I have found it beneficial to design systems with immutable data types (some, most or even all). Often when I do so, I find ...
9
votes
6answers
1k views

Significant amount of the time, I can't think of a reason to have an object instead of a static class. Do objects have more benefits than I think? [closed]

I understand the concept of an object, and as a Java programmer I feel the OO paradigm comes rather naturally to me in practice. However recently I found myself thinking: Wait a second, what are ...
8
votes
2answers
2k views

How is it possible to write the compiler of a programming language with that language itself [duplicate]

Possible Duplicate: How could the first C++ compiler be written in C++? You probably heard that Microsoft released a new language called TypeScript which is a the typed superset of JavaScript. ...
45
votes
9answers
14k views

Are classes with only a single (public) method a problem?

I am currently working on a software project that performs compression and indexing on video surveillance footage. The compression works by splitting background and foreground objects, then saving the ...
27
votes
3answers
7k views

What is the principle of least astonishment?

In programming what is called Principle of Least Astonishment? How is this concept related to designing good APIs? Is this something applicable to only object oriented programming or does it permeate ...
18
votes
8answers
4k views

Is perfectionism a newbie's friend or enemy? [duplicate]

Possible Duplicate: Where do you draw the line for your perfectionism? I see that the development community is very focused on doing things the right way and personally I would like to do the ...
29
votes
3answers
4k views

Does TDD lead to good design? [duplicate]

I'm in transition from "writing unit tests" state to TDD. I saw as Johannes Brodwall creates quite acceptable design from avoiding any of architecture phase before. I'll ask him soon if it was real ...
10
votes
6answers
3k views

What are the practical ways to implement the SRP?

Simply what are the practical techniques people use to check if a class violates the single responsibility principle? I know that a class should have only one reason to change, but that sentence is ...
47
votes
3answers
50k views

Which is a better practice - helper methods as instance or static?

This question is subjective but I was just curious how most programmers approach this. The sample below is in pseudo-C# but this should apply to Java, C++, and other OOP languages as well. Anyway, ...
22
votes
4answers
4k views

Architectural differences between dynamic and static languages

Are there any major architectural differences when designing applications that will be built on static languages (such as C# or Java) and dynamic languages (such as Ruby or Python)? Which are the ...
8
votes
9answers
799 views

Internationalization : What things to think about?

I was listening to Jon Skeet's talk at the last StackOverflow Dev Days and he piqued my curiousity regarding internationalization. Suppose I have a waffle-making program, either complete, or still in ...
12
votes
6answers
10k views

Are Get-Set methods a violation of Encapsulation? [duplicate]

Possible Duplicate: When are Getters and Setters Justified In an Object oriented framework, one believes there must be strict encapsulation. Hence, internal variables are not to be exposed to ...
2
votes
2answers
572 views

Law of Demeter and its applicability

Let's say I'd like to perform the following command: house.getFloor(0).getWall(WEST).getDoor().getDoorknob(); To avoid a NullPointerException, I'd have to do the following if: if (house != ...
27
votes
3answers
42k 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 ...
12
votes
4answers
2k views

How much design to do first? [duplicate]

I have never worked with a professional software development team. As such, analyzing and thinking about each and every aspect of my software does not come naturally to me. Whenever I strike an idea ...
69
votes
4answers
7k views

Why were Java collections implemented with “optional methods” in the interface?

During my first implementation extending the Java collection framework, I was quite surprised to see that the collection interface contains methods declared as optional. The implementer is expected ...
13
votes
7answers
2k views

Should a surrogate key ever be exposed to a user?

Often in a table that has no natural key, it is still useful for users to be able to have a uniquely generated identifier. If the table has a surrogate primary key (and in such a case you would ...
1
vote
3answers
2k views

Compiler/OS Design - Where to start [closed]

I have a fairly strong background in C and Assembly and I am starting to look into basic compiler and operating systems design, but my biggest problem is where I should really start, seeing as both ...
5
votes
4answers
610 views

Passing compound object for parameters

I have different data modules, which take a couple of parameters from a configuration list. Do you think it's ok to pass a configuration object as a whole module1(config) and let the module pick what ...
14
votes
0answers
4k views

Design and Development Methodologies for the single developer

At my work, typically the developers here all work separately, we may share projects but often only do so when another isn't working on it (for reference, we're a consulting company. So someone may ...
12
votes
4answers
1k views

Is a common library a good idea?

I've always thought that a "common library" was a good idea. By that I mean a library that contains the common functionality that is often needed by a few different applications. It results in less ...
21
votes
6answers
5k 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 ...
66
votes
7answers
149k views

Designing a REST api by URI vs query string

Let's say I have three resources that are related like so: Grandparent (collection) -> Parent (collection) -> and Child (collection) The above depicts the relationship among these resources ...
71
votes
4answers
19k views

Why do many software developers violate the open/closed principle?

Why do many software developers violate the open/closed principle by modifying many things like renaming functions which will break the application after upgrading? This question jumps to my head ...
36
votes
11answers
6k views

Concurrency: How do you approach the design and debug the implementation?

I've been developing concurrent systems for several years now, and I have a pretty good grasp on the subject despite my lack of formal training (i.e. no degree). There's a few new languages that have ...
27
votes
9answers
5k views

How do you organize highly customized software?

I'm working on a large software project which is highly customized for various customers arround the world. This means that we have maybe 80% code which is common between the various customers, but ...
47
votes
6answers
5k views

Business logic: Database vs code [duplicate]

I'm a student of systems engineering, and all my teachers and friends (that actually work in the area) say that it is better to have as much logic as possible implemented in the database (queries, ...
35
votes
3answers
20k views

Should I use a config file or database for storing business rules?

I have recently been reading The Pragmatic Programmer which states that: Details mess up our pristine code—especially if they change frequently. Every time we have to go in and change the code to ...
59
votes
16answers
6k views

How do I deal with analysis paralysis?

Very frequently, I am stuck when choosing the best design decision. Even for small details, such as function definitions, control flow, and variable names, I spend unusually long periods perusing the ...