A design pattern is a general reusable solution to a commonly occurring problem in software design.

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2answers
375 views

Choosing the right Design Pattern

I've always recognized the importance of utilizing design patterns. I'm curious as to how other developers go about choosing the most appropriate one. Do you use a series of characteristics (like a ...
0
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3answers
146 views

Doesn’t active record violate SRP and OCP?

I have watched the active record classes in our project grow into large, do-it-all classes. When you need anything about a user, for example, you should go to the Person class. While this makes ...
7
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3answers
331 views

How to decompose / model a chessboard

As someone new to programming, I am building a chess web application in JavaScript, both for fun and to learn more about design patterns. I keep running into a wall, which is how to decompose the ...
3
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4answers
256 views

Testing all combinations

I need to do some performance measurements inside my application. I want to measure, change some parameters, measure again. There are different algorithms I want to test, and there are various ...
0
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2answers
126 views

Best way to display domain object summary information efficiently and in an OO way from a large inheritance tree?

I've provided only simplified code as it's more of an abstract design question. So I have many, many nested business/domain event objects, e.g. public class Event { //bunch of properties and ...
3
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2answers
317 views

Design pattern for overlapping actions and animations?

Is there a design pattern for dealing with overlapping UI actions and animations? A few examples: Let's say I have an interactive table row that expands to reveal an extra control when the user ...
0
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1answer
134 views

Practical Use of Depency Injection (IoC) Container

I am creating a MVC-ish framework in PHP. I am trying to implement a DI Container to allow the creation of controller objects (among others). My MVC framework is pretty typical. Each module (or ...
3
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1answer
1k views

Opensource showcase for MVC in Java Swing [closed]

I've allready created small desktop CRUD applications using Java/Swing. In hindsight I'm not quite sure if the overall design of these applications is good. I've also done some reading on MVC and ...
5
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2answers
225 views

Is Convention Over Configuration “Knowledge in the World” or “Knowledge In Your Head”?

In Don Norman's seminal work "The Design of Everyday Things", the author coined the phrases and explains the difference between "Knowledge in the World" and "Knowledge In Your Head"; an example of ...
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0answers
54 views

Design of a custom query result array with lazy loading

I have a database that generates a query result array, each position of the array being a hash like object. Since each array item must be mapped into a well defined class, I decided to implement an ...
0
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1answer
86 views

What is the shortcoming of custom factory comparing to generic factory [closed]

I have a factory method as given below public class AutomobileFactory { Dictionary<string, ICar> internalFactory = new Dictionary<string, ICar>(); public AutomobileFactory() { ...
1
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1answer
291 views

Creating a online database creator

I've been thinking of creating an online database creator (think DabbleDB, Zoho Creator, Intuit Quickbase, etc.). I've been thinking of a couple solutions: Have 4 database tables: Tables, Rows, ...
3
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4answers
225 views

How to handle affinities?

Assume we have an abstract class having several concrete classes which interfaces publish an information under several equivalent forms, with the difference that each class has a preferred form which ...
0
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1answer
150 views

Design and write my own logger engine [closed]

I know that in this way I could reinventing the wheel, but my logging needs are quite unusual and I don't know how to achieve this unusual result with log4net, last (but not the least) I would catch ...
-1
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1answer
134 views

Naming convention of getters and setters [closed]

Given a string variable variable, for example, the convention to expose it is: public class SomeClass { public String variable = ""; public String getVariable() {return variable;} public void ...
27
votes
7answers
4k views

Is dependency injection essential for unit testing?

Is using dependency injection (DI) essential for unit testing? I can't think of another alternative for isolating code so it can be tested. Also, all the examples I have ever seen use this pattern. ...
4
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3answers
199 views

Designing a fitness / weight lifiting routine database

I'd like to create an app similar to Barbell Pro for Android, for practice / interest / educational purposes really. Or even as another example for database purposes, Fitocracy The problem is, I ...
1
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4answers
177 views

available methods change with object state

I'm programming a graph object which can be in either a mutable or immutable state. In both states, it has a get method, but only in the mutable state is the set method allowed. The transition occurs ...
2
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1answer
214 views

DI or Factory Pattern ? Both ? or a different apprach?

Lets say we have an abstract class called BaseSwitch, inherited by concrete implementations Switch A and Switch B, Each Switch representing a real-life switch (A telephony tool which among its ...
215
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13answers
49k views

So Singletons are bad, then what?

There has been a lot of discussion lately about the problems with using (and overusing) Singletons. I've been one of those people earlier in my career too. I can see what the problem is now, and yet, ...
1
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3answers
205 views

Pattern for costly precondition check before acting

Let's say I have a method DoTheThing() which requires the precondition-check CanTheThingBeDone() to return true. The latter method is time consuming as it accesses the database. I'm finding it hard ...
9
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2answers
3k views

Understanding the bridge design pattern

I do not understand the "bridge" design pattern at all. I have gone through various web sites, but they haven't helped. Can anybody help me in understanding this?
1
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1answer
99 views

Factory method - when objects need information to get initalized

Lets look on a simple example: assume that I have three classes implemeting IPersonRepository: SQLPersonRepository, WebPersonRepository, InMemoryPersonRepository. I also have PersonRepositoryFactory ...
3
votes
3answers
279 views

Why should a builder be an inner class instead in it's own class file?

Many Builder Pattern examples make the Builder an inner class of the object it builds. This makes some sense since it indicates what the Builder builds. However, in static a static type language we ...
0
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2answers
146 views

How to remove redundant code that enables button. Or “if” statement

I got probably "micro optimization" problem. I got "History number", "Next Number", "Reset" buttons, as well "label" for text. Every time I click At "Next number" button I would like to show random ...
22
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7answers
7k views

Self-Executing Anonymous Function vs Prototype

In Javascript there are a few clearly prominent techniques for create and manage classes/namespaces in javascript. I am curious what situations warrant using one technique vs. the other. I want to ...
5
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1answer
426 views

Is there already a commonly known name for the 'ensure pattern'?

I use a pattern that I call "ensure" extensively in my repository layer. In short, it does the following when I call an Ensure(...) method: It uses the arguments in the method to attempt to ...
1
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2answers
309 views

Why does java.util.Calendar use static factory methods?

It is considered better to have a separate factory class than having static methods in same class. See this question. But the standard API uses both approaches. Separate factory: ...
3
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3answers
374 views

Why is inheritance only defined at compile-time?

I found this statement from the gang of four's "Design Patterns" particularly odd; for some context, the authors are comparing inheritance versus composition as reuse mechanisms [p. 19]: "...you ...
3
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1answer
233 views

State pattern vs Inheritance

In the following image for the State Pattern from Applying Domain-Driven Design and Patterns: With Examples in C# and .NET I'm trying to persist the SalesOrder entity into the database. Normally I ...
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8answers
19k views

Web Developer interview questions

I read an article today that listed some basic questions about web development: Describe how POST data was submitted to a server by a browser. Explain a number of HTTP status codes (except maybe 404 ...
0
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1answer
194 views

Anemic domain models - what sort of methods a domain object might need?

This question might seem strange, but it's something I've faced sometimes. I've been trying to adopt DDD, however I'm always facing the problem of anemic domain models. The problem is that when I ...
0
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3answers
204 views

Are design patterns essential for good code? [duplicate]

Are design patterns (e.g. factory pattern, observer, etc...) required to be known to write good code? I often have no idea of what people mean when they talk about inserting pattern name here pattern ...
0
votes
1answer
168 views

Need an OOP pattern or strategy for “pluggable” property

I'm using OOP and MVVM in a WPF c# application. The goal is for the resulting object (data-bound to user interface) to accurately represent a product. One specific area of the product is highly ...
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1answer
170 views

Notifying multiple listeners

I am building an Android guitar application and I need a way for GuitarString objects to notify multiple listeners that it has just been played. This includes the current Activity and all instances of ...
6
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3answers
4k views

How to make an ASP.NET MVC site modular

I'm in the planning stage for an employee intranet system to be built with ASP.NET MVC 4. We'd like the site to consist of separate "modules", each of which provides a different feature: messaging, ...
1
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1answer
241 views

Creating a System Sequence Diagram from an [extended] use case

As I have been taught - one controller = one use case. But I have: OutsiderController SupplierController (which extends OutsiderController) SubContractorController (which also extentds ...
1
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2answers
229 views

What design pattern (in python) to use for properly seperate runtime infos with core code?

I am not sure if this is a clear question. I work on a python project that is based on terminal(console), for which I am planning to implement a GUI. I am not major in CS so I really have no idea ...
0
votes
1answer
112 views

detect if a combination of string objects from an array matches against any commands

Please be patient and read my current scenario. My question is below. My application takes in speech input and is successfully able to group words that match together to form either one word or a ...
0
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2answers
105 views

How does one design his various architecture/business models?

I'm currently learning about various application design approaches and there's one thing I can't really get my head around. Let's say I have a physical device in my network, an IP surveillance ...
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4answers
7k views

How to avoid big and clumsy UITableViewController on iOS?

I have a problem when implementing the MVC-pattern on iOS. I have searched the Internet but seems not to find any nice solution to this problem. Many UITableViewController implementations seems to ...
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votes
1answer
1k views

Singleton: Is Singleton an Anti-Pattern [duplicate]

Was reading an interesting blog post on Singleton design pattern which is so widely used. If it's stupid or as in some quora posts, its an anti-pattern why is it so widely used even in frameworks. ...
1
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1answer
137 views

Optimizing mindmaps by finding the least amount of redundancy

When using mindmaps, you order them based on how you think it fits best. So for instance (tab means subtree) requirements dinner food forks spoons breakfast food forks this ...
1
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2answers
162 views

Modeling an extensible Domain Driven Design project

Say that we are developing an application with modules (Sales, Accounting, Purchasing, etc). An example case here is : Sales module is the basic / primary module available, and Accounting module is ...
2
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2answers
2k views

Should angularjs directive directly interact with services or is it considered an anti-pattern?

Which one is considered better: having a directive that interacts with services directly or having a directive that exposes certain hooks to which controller may bind behaviour (involving ...
1
vote
3answers
117 views

How to conceptually consider and implement user interface rules for numerous controls and data inputs?

I have a user interface with numerous controls and data inputs on it. Buttons, text fields, and checkboxes, etc. Imagine the following "rules" exist for a sample UI with 2 of those controls: B2 ...
3
votes
2answers
153 views

What are the advantages of dynamically binding a method to class instance?

I came across Instagram's API client written in Python. In their class InstagramAPI, they bind the methods to a function in bind.py. When called, the function returns an instance of the class ...
4
votes
1answer
542 views

Design patterns for multi-threaded messaging server

I'm designing an instant messaging server as a personal exercise to improve my understanding and application of multi-threading and design patterns in Java. I'm still designing, there's no code yet. ...
0
votes
2answers
624 views

Designing application flow

I am creating a web application in java where I need to mock the following flow. When user trigger a certain process (add product to cart), I need to pass through following steps Need to see in ...
0
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2answers
311 views

Why separate class CommandHandler with Handle() instead of handling method in Command itself

I have a part of CQRS pattern implemented using S#arp Architecture like this: public class MyCommand { public CustomerId { get; set; } // some other fields } public class ...