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

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Should I expose a “computed” value as a property or a method?

I have a C# class that represents a content type in a web content management system. We have a field that allows a web content editor to enter an HTML template for how the object is displayed. It ...
0
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2answers
196 views

Factory Method vs. Factory Method design pattern

I am currently studying design patterns from the book (which, although I didn't try anything else, I find excellent) Head First Design Patterns. I'm confused about two concepts: The Factory Method, ...
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1answer
84 views

reloading singleton classes and dependency

I have a singleton object. It's a DAO that looks somewhat like this (pseudoish code): class UsersDAO { public usersDAO init(string sDSN){ variables.sDSN = sDSN; return this; } public ...
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3answers
114 views

When to use tools vs custom development? [closed]

To learn dependency injection in a current side-project, I am writing my own dependency injection container. But this has lead me to wonder, at what point is it worthwhile to use a third party ...
0
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1answer
129 views

Why can't the Factory Method pattern create a family of objects? [duplicate]

There are two main differences between the design patterns Factory Method and Abstract Factory. Difference 1 is that Factory Method is mainly based on inheritance. A class in a way uses it's subclass ...
3
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3answers
148 views

Why should one subclass instead of composite when using the Factory Method design pattern?

I'm currently learning about design patterns. I learned about the Factory Method pattern. This pattern means that in order to implement a factory to create objects, one should subclass the class that ...
5
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4answers
347 views

How much effort should I invest in creating loosely coupled designs?

I am currently learning about design patterns. I think most people would agree that these patterns are great tools, but should be used with moderation and not as the answer for everything. Using them ...
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1answer
178 views

Interface questions for using Command Pattern and Dependency Injection together

I have many projects that have essentially the same high level requirement: test all hardware on a device. Each device can have a different communication protocol, requires different test equipment to ...
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3answers
140 views

Does this in the Observer pattern count as composition?

In a classic implementation of the Observer design pattern, the subject has a list of references to all of it's observers, and each observer might have a reference to it's subject. Is this considered ...
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2answers
142 views

Java Method Returns Unbounded Type

I was reading this article, https://weblogs.java.net/blog/emcmanus/archive/2010/10/25/using-builder-pattern-subclasses, about subclassing a builder class. I understood the article but there was one ...
2
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1answer
319 views

xml serialization and deserialization complex situation

I'm considering passing xml back and forth for error messages but each error has different scenarios. one situation at hand is passing diffed text comparison while others are as simple as passing a ...
19
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8answers
2k views

Do Design Patterns Stifle Creativity

Many years ago, I was talking with an Economics professor about design patterns, how they were establishing a common language for programmers and how they were solving well known problems in a nice ...
0
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2answers
129 views

Best design pattern for library with data model

I am refactoring an old Codeigniter library to be php framework agnostic. There are these core parts: the connection object - this will come from the "user"; ie, the framework's connection, or their ...
-1
votes
1answer
182 views

How to create a some kind of value for sentences? [closed]

I want to identify most matching sentence using some pattern. That means by using java algorithm I want to create identical value for each sentences.Each sentence when entering to that algorithm can ...
1
vote
3answers
148 views

How do I evaluate if an Orchestration is the appropriate design pattern for a given problem?

Say that you're doing a code review, and you find yourself faced with an orchestration pattern: class OrchestrationClass { private Configuration _configuration; private DataStore1 _dataStore1; ...
3
votes
1answer
246 views

What is the difference between Repository Pattern and Facades Pattern?

I've always used the repository pattern in my applications. But I have seen that many people use facades instead of the repository for naming convention, but the operation is the same, I Think. Why is ...
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0answers
20 views

Composite repository with plugins for multitenant app

Im working on an app that has flexible storage configuration. For example: public class Repo1:IRepository { public void DoSomething(int tenantId, string someKey) { ... } } This ...
1
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2answers
98 views

How to build configurable forms?

I'm working on two separate projects now that are essentially just CMSs -- a bunch of forms for recording various bits of information. Each project is built to serve many clients, and each client ...
4
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2answers
239 views

How to decouple simple factory and default implementation?

I have a simple factory class (FileResources) with static factory methods providing a default implementation (DefaultFileResource). public final class FileResources { private FileResources() {} ...
2
votes
1answer
130 views

Does a repository belong in this project?

I have a project that gets all of its data from API calls. The server that hosts this API connects with it's own database (not even sure what DB it is, etc). More or less the idea of a repository is ...
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0answers
57 views

Is Factory method subclass of Abstract factory in essence [duplicate]

Is it correct to say that factory method is essentially just a particular case of the abstract factory which produces the only one object not a group? I know that classic realizations assumes the ...
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3answers
274 views

Global request context - anti-pattern?

I was talking today to a colleague of mine about Python web frameworks and our impressions about them. I told him I think Flask having a global request smells badly and is an anti-pattern. The docs ...
3
votes
2answers
164 views

Is it an acceptable practice to Get a property, that involve parsing binary, that might throw an exception?

I have a property that is loaded lazily, any time after the ctor is called. It is possible that the binary that my property relies on is invalid. If invalid I might have to throw an exception. ...
0
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0answers
65 views

Difference between class clusters and abstract factory in cocoa

I have read that Obj-C class clusters are an implementation of the abstract factory. Can anyone explain if there are any differences between the 2 as design patterns. I read somewhere that there are ...
0
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3answers
170 views

Is the Adapter the correct design pattern for this situation?

I have an instance of a class UntouchableClass of which I need to access the member variables to use in my DotLiquid template. Problem is, UntouchableClass has to inherit from Drop if I want to use it ...
4
votes
2answers
221 views

How is the publish-subscribe pattern different from gotos?

My understanding is that Goto statements are generally frowned up. But the publish-subscribe pattern seems to be conceptually similar in that when a piece of code publishes a message, it performs a ...
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vote
5answers
633 views

How do I deal with global variables in existing legacy code (or, what's better, global hell or pattern hell)?

So... We have this fairly complex project (~10k LOC, but there's duplicated code so it's hard to tell) with hundreds of global variables. The project has more dependencies on other projects, and many ...
2
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3answers
327 views

Design for creating a menu based on user type

Problem I am building a PHP application which has a main menu, which in turn contains various "sections" or "subheadings" with various links. There are several user types such as SuperAdmin, Admin, ...
4
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4answers
258 views

Design pattern for bidirectional signals/events

This problem feels rather basic, yet I've never known a great solution. I'm looking for a way for components in an application to notify each other while being as decoupled as possible (both at ...
0
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2answers
148 views

Whats an Ideal way to pass rules/options to methods that build SQL

We're trying to come up with a way to handle code that builds dynamic SQL for our application, which is very database centric. Things like Linq to SQL and Entity Framework are out of the question, so ...
0
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3answers
172 views

“Property Container” design-pattern in-depth definition

Could anybody, please, explain what is a Property Container or at least where can I get information about that pattern on the Internet? I've found that it exists as one of the Fundamental patterns in ...
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2answers
145 views

Validating objects with each other - Design Pattern needed

I am running a zoo application. My zoo includes an abstract class of 'animal', and several deriving classes - 'zebra', 'elephant', 'orangutan', 'baboon' and so on. Of each class I have several ...
3
votes
1answer
224 views

Is it bad to have classes as properties of all other classes?

I've been making MVC programs for work (I'm an intern) and I feel like I'm doing a pretty good job at abstraction, single responsibility, etc. But I have this feeling about how I keep making objects ...
3
votes
1answer
157 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 ...
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2answers
169 views

Why does a monad use “return” or “unit” rather than “lift”?

This is partly genuine curiosity, and partly a check on my understanding. I'm probably missing the point. In Haskell, why does a monad use operations called return or unit to describe putting a type ...
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1answer
147 views

Web design pattern

I am building a small website, in PHP and I am using MVC design pattern for the UI. In the future I will need to add mobile support for my website. It will be in the sub domain "m" like everyone. All ...
2
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2answers
216 views

Pattern for multiple datasources

I've already read this question on CodeReview. I was hoping for general advice. I'm writing a service which will go to numerous data sources. Each source requires getting copious amounts of data ...
0
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3answers
170 views

Is it ok for services to reference one another?

I have a service that needs information implemented by another service in the same layer. Is it good practice for one service to take a dependency on another service in the same layer?
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0answers
29 views

DSL enabling users to reference forms and records to display?

There are three main "unique" components to my system: Visual form builder (AngularJS backed); generates an id CRUD automatically available for it at /form_type/id "Aggregate page"; with a form ...
0
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3answers
268 views

Software architecture which allows for growth, real life situation [closed]

I know of Interfaces, Abstract classes that serve as Base class, I've been reading up on loose coupling, ... But I can't come up with a decent solution when a property of a class changes, and the new ...
5
votes
2answers
197 views

Branch twice for unique condition

Consider an application that displays only Foobars belonging to themselves to normal users, and all Foobars to admins: -- Normal users: SELECT * FROM Foobar WHERE user_id=:user_id; -- Admins: SELECT ...
5
votes
1answer
243 views

Layers and layers of SOAP

I am designing the back-end to a SOAP web-service and have a question about how I am thinking of doing it. I am going to go with a simple layered design which consists of 3 separate layers. Layer 1 ...
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0answers
44 views

Putting together Data Mappers and Domain Objects inheritance

Currently, I have a system with a Data Mapper and multiple Domain Objects which inherit from the same class, let's say B and C that inherit from abstract class A. In order to retrieve data, I need to ...
0
votes
1answer
304 views

Migrating old Asp.net 1.1 project to mvc 3 or 4

we have to migrate a very old project that are having more than 500 web forms and 400 tables and it is hugely depends on stored procedures, the current specification is: Asp.Net : .NET version 1.1 ...
0
votes
1answer
215 views

sqlite trigger or application event?

I've have two event queues(table mapped queues) based on two different states of same data stored in two different tables. The events are generated on create/update/delete on both the tables. ...
1
vote
4answers
228 views

In MV* pattern where does non-business model goes?

I am passing Menu items to View from ViewModel. My menu definition is a model with properties title, image, hasChildren and isEnabled. But this model is meant for UI unlike business domain models like ...
0
votes
0answers
200 views

Javascript design pattern with jQuery Widget factory

I am using the jQuery widget framework for creating some graphical elements on a webpage, and I have a conseptual question about the overall structure of the code. I have 3 classes A, B and C which ...
2
votes
1answer
265 views

Javascript Implementation Patterns for Server-side MVC Websites

I'm looking for information on common patterns for initializing and executing Javascript page by page in a "traditional" server-side MVC website architecture. A few months ago, my development team ...
0
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0answers
165 views

Should you implement a repository pattern with an MVVM javascript framework?

When coding a MVVM pattern I use Dependency Injection (DI) and try and code against interfaces. One of the common patterns is a Repository pattern, so I can swap my data storage provider. If I'm ...
0
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2answers
294 views

Where should the ACL handler be called in a MVC architecture?

Thinking about Access Control Lists bound to a web MVC architecture, I have a doubt on where the verification should be done. Within Models? Controllers? FrontController? Imagine a multiple module ...