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

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Is this the solution to static inheritance?

I've seen a lot of posts recently on why Singletons should be avoided. However, I can't see any of those problems with the following solution to a common problem: static inheritance. For example, I ...
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1answer
299 views

Pattern to use to relate multiple data sources to different user data widgets

I have an client x server intranet application the basically gets data from the server, format it and send that data to the client for display. At the server we are using ASP.NET C# running on IIS ...
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78 views

in trouble making a card game with pygame

I am designing a card game playable against the computer. The rule is very simple Both player and CPU gets 10 cards of 1 to 10. Player and CPU plays a single card at the same time, every round. The ...
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How to use one web page to create and edit database entries

My team and I are developing a java web application which allows our admins to create and edit "methods" which can later be viewed by other users. We are currently discussing the best way to ...
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2answers
78 views

Design Pattern - DLL per Strategy

I usually found myself designing my application in the following way: One DLL containing interfaces for a desired subsystem. For example, Company.Framework.Persistence.dll. One new DLL per each ...
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4answers
1k views

Avoid having an initialization method

I have this existing code where they have a class and an initialization method in that class. It is expected that once the object of the class is created, they need to call initialize on it. Reason ...
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1answer
113 views

Best solution to switch between new and deprecated code

We have a feature that is currently implemented, let's call it implA. ImplA works but can't do many things. So we have decided to rewrite it. But we can't just replace it right away, so we will need ...
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74 views

Middleware dependencies

I'm trying to convert a legacy PHP app to use the middleware paradigm, similar to connect/express.js. I've started porting the code into separate middlewares so that every feature is neatly self ...
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31 views

Command Pattern for Logging/Backup/Testing

I need your input guys on this concept I intend to implement: Use the Command Pattern to record everything in my app. It should encapsulate every single user action and micro-action as a Command and ...
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1answer
45 views

Design pattern for mapping data fields

I have seen this problem a few times and never can come up with a solution i like. System A Sales Order Entity order_id created line_items_count System B Sales Order ...
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1answer
66 views

Application development with fully dynamic controls and processes based on database

All software development projects are moving into separation of design, logic , data in patterns like MVC , MVVM and others. Strangely i got a very strange requirement for a new software; that is : ...
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3answers
210 views

Decorator design pattern in swift

Im reading "Head first design patterns" (here you can find exact example mentioned in book) While going through Decorator design pattern, everything was crisp and clear until i stumbled into this ...
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3answers
133 views

What is the most efficient way to find a set of locations within a radius of a certain point?

Imagine a dataset of all the restaurants in the US (similar to Yelp, etc), how would you return a set of restaurants within a certain range of a particular zip code. (Assuming you have already a ...
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56 views

Addicted to Interfaces - Good or bad? [duplicate]

After 2 years of programming, I usually found myself using the following design pattern: public interface ISomeInterface { void SomeMethod(); void OtherMethod(); } public abstract class ...
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1answer
92 views

Design pattern for ensuring the “signature” of generic lists is equal

I have an interface, Attribute, that is going to be implemented in various ways, class AttributeA implements Attribute{\\..} class AttributeB implements Attribute{\\..} Then I'm planning to have ...
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3answers
152 views

Design patterns for implementing optionally supported features

Here's the original problem. There are two classes: Protocol and, say, ProtocolUser (which actully uses the Protocol class instance). Now, I need to support multiple protocols, whose feature sets only ...
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1answer
56 views

Efficiently extracting data from pdf with a template system?

basically allow a user to label specific text in a pdf file. Use the label information to create a template, which a script uses to extract text from specific pdf. What would be a good pattern to use ...
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2answers
252 views

Sharing code logic between controllers, through the Model layer?

As I originally conceived my Model layer, it was only supposed to hold data and no code. I receive DTOs from web-services, they are mapped into my Model objects. Those model objects usually end up ...
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2answers
538 views

Is factory pattern a right pattern for the situation described here?

Is factory pattern a right pattern when we want to consolidate the related objects? Problem - In the Set-top box, I have a user-io, basically the interface to control the settop box - The user-io can ...
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4answers
1k views

How to force “program to an interface” without using a java Interface in java 1.6

In java 1.8 they have wonderful new "default interface methods". In 1.6 how close can we come? The goal: use code to keep clients from being able to tell that a class is not a java interface. If we ...
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2answers
89 views

How can I have objects interacting and communicating with each other without forcing a hierarchy?

I hope these ramblings will make my question clear — I'd totally understand if they wont, though, so let me know if that's the case, and I'll try making myself clearer. Meet BoxPong, a very ...
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4answers
17k 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 ...
2
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1answer
203 views

When do I reuse or create a new Builder

I've implemented a Builder Pattern in a project I'm working. I'm using this design pattern to created Fields and Components (div, tables, panel (boostrap)). So I have a Director Component class. It ...
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1answer
278 views

Change routing to comply with Law of Demeter

I have a Task, Owner and Plan. Charge values are kept in a plan, owner is on a particular plan and task knows its owner. A task needs to setup its charges based on the knowledge the owner has. Owner ...
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42 views

Android, access 1 activity from 2 cases, what design pattern is this?

I'm developing an Android app, encounter this case. There are 2 ways we can enter an activity (named activityB): either from activityA or from notification. 1st case: ActivityA -> activityB 2nd ...
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5answers
992 views

Amateur question about corrupt software [on hold]

I was hoping someone here could help a non-coder with just a few questions to give some realism to a no-budget film. I am currently writing a screenplay in which the main character's analytic ...
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2answers
101 views

Are the Repository Pattern and Active Record pattern compatible?

Currently I am developing a webapp where I have defined models implementing the Active Record pattern. Each model also is defined by an interface that specifies the Entity properties and makes it easy ...
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2answers
126 views

Designing Message class in Java

I'm writing a class for Message. Message comes with Header and Payload. Header has following fields: Version Type For Type "XYZ", the following Payloads are allowed. Configuration Metafile ...
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2answers
81 views

What is the better way of getting different outputs for two very simmilar related workflows

I have a very concrete scenario but I think it would be quite frequent. I'm trying to come up with a solution that it's "better" by better meaning more scalable, reusable and not smelly. I'm working ...
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3answers
102 views

Would implementing a “Throwable Event System” be abusive?

I have been thinking for a couple years now about using Throwable events and implementing a sort of event system that uses throw to dispatch an event, or let a different method handle it with throws. ...
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4answers
483 views

Is Visitor Pattern valid in this scenario?

The goal of my task is to design a small system which can run scheduled recurring tasks. A recurring task is something like "send an email to administrator every hour from 8:00 am to 5:00 pm, Monday ...
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2answers
85 views

In javascript, should object properties be declared on top of the function?

I learned that it's good practice to declare variables before they are used. For example: function myFunction() { var i; var j; } Does the same thing go for object properties, and is there a ...
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0answers
35 views

Which patterns to apply for “User Manager” [closed]

I developing a social application and I neeed to create a User Manager that is responsible for managing certain types of user. A user who enters in to the system will be a new user or an existing ...
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1answer
47 views

File validation rules

I have an application that can accept CSV files to run some operations. The files look like: CREATE USER:username,last_name,first_name,age user1,Smith,John,23 user2,Poppins,Mary,257 There are a ...
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1answer
308 views

What is better repository design?

I have tables that I insert, delete and update, but I read from views. At times, I may read from the tables as well. What is a better generic interface for a Repository: public interface ...
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1answer
382 views

Which patterns/architecture to apply for “Import Data, Process Data, Export Result”

I was wondering which architecture/patterns to choose for the following problem divided into three steps: Import TestScript Description from File (e.g. .xls, .txt) Process Described TestScript ...
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2answers
626 views

Repository pattern implementation that knows nothing about the database table and column names

I've seen around the Internet and Github, implementations for the design pattern Repository that knows about database table and column names. I was think, if I want to work with the database as a ...
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1answer
115 views

Differences in design/thought process for OO in Java and JavaScript [duplicate]

Despite sharing a similar name and syntax, Java and JavaScript are quite different. However, they both have Object Oriented features. As a JavaScript novice, the main differences that I can see ...
54
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3answers
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What is the “Free Monad + Interpreter” pattern?

I've seen people talking about Free Monad with Interpreter, particularly in the context of data-access. What is this pattern? When might I want to use it? How does it work, and how would I implement ...
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1answer
67 views

Encapsulating mutable objects with special structure in Python

I am writing a library for working with special types of trees, called Foo trees. A Foo tree has very special structure. There some operations, called bar and baz, which only make sense on Foo trees. ...
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2answers
200 views

which one is recommended object-oriented design? [closed]

I made simple object-oriented prgram, and think about design. I wonder which one of belows is recommended object-oriented design. Most left side class is "Main" class. Black arrow means they are "Has ...
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1answer
63 views

how can the presenter or view interact with the model in the MVP pattern?

I'm learning the MV* patterns. MVP in this case. I'm trying to refactor an old android application into the MVP pattern to make things less tightly coupled, but I'm struggling one one concept. I know ...
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2answers
191 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 ...
6
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1answer
441 views

Can Test-Driven development work in legacy projects?

So here is a question for you, having read some great answers to questions such as Test-Driven Development - Convince Me. So my question is: "Can Test-Driven Development be used effectively on ...
3
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3answers
158 views

Design suggestions for converters in Java

I'm trying a set of converters which will convert an object to some older form. And there are different objects which are converted. By older form I mean changing the values of some fields and in case ...
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1answer
48 views

Generic PHP web interface for handling concurrent updates optimistically

I'm looking in to writing a new PHP based CMS which handles concurrent edits optimistically like source version control rather than pessimistic locking like Wordpress. I want to be able to write some ...
1
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1answer
100 views

DI container with multiple instances of same object

I'm looking for idea to make a DI container that can store multiple instances of the same object. Usually, a DI container should store either a single instance of the object, or create new object each ...
3
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3answers
342 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 ...
11
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4answers
2k views

Create a behavior/Component based system for games

Background I do game development as a hobby, and am looking for a better way to design them. Currently, I am using a standard OOP approach (I have been doing enterprise development for 8 years so it ...
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1answer
264 views

Where and how to reference composite MVP components?

I am learning about the MVP (Model-View-Presenter) Passive View flavour of MVC. I intend to expose events from view interfaces rather than using the observer pattern to remove explicit coupling with ...