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

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What design pattern best suits managing handles to objects, without passing handles or Manager around?

I'm writing a game in C++ using OpenGL. For those that don't know, with the OpenGL API you make a lot of calls to things like glGenBuffers and glCreateShader etc. These return types of GLuint which ...
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5answers
341 views

Separate interface for mutation methods

I've been working on refactoring some code, and I think I may have taken the first step down the rabbit hole. I'm writing the example in Java, but I suppose it could be agnostic. I have an interface ...
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4answers
188 views

Design Pattern for retry and error handling

I'm trying to find a good design pattern, or perhaps series of patterns, for injecting error handling and retry handling when getting data from a webservice. For instance, I have: do { //get the ...
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3answers
138 views

Nested POJOs, exposing collections, detecting changes

I have a couple plain object classes to represent data read from a file. They look something like this: public class Command { private String name; private List<Message> messages; } ...
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1answer
97 views

When applying the interface segregation, should you separate interfaces for regular setters and mathematical operations?

When applying the interface segregation, should you have separate interfaces for a straightforward setters and interfaces that perform an operation before setting? For example, say you have a class: ...
5
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1answer
189 views

PHP: Injecting the same database connection into multiple objects

Suppose that there are two classes that define objects of vastly different function such that in the datastore, the information they require is divided into two separate databases. For example, the ...
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2answers
88 views

Efficient way to handle foreign keys

I am building a script that checks a large network of sites for invalid links. The idea is to flag links that continuously show as not available so that they can be cleaned by the administration team. ...
2
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2answers
175 views

Has-A or Is-A or some strategy pattern?

I am developing a web based application which is about tracking Fleet units. Actually i have already developed the system but in the last six years things changed a bit. Ordinary the software ...
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40 views

What sort of design pattern should I be using here - Tabs Generation

I am fairly new with design patterns, I have been studying them but no practical experience so this is going to be my first try, Graphical representation of GUI is shown in this diagram, Points ...
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1answer
110 views

Expandable alternative to Visitor pattern for tree traversal?

I have a tree containing various subtypes of the my base node class. I now want to traverse this tree and do something with the nodes depending on their type. The most straightforward idea is to just ...
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1answer
87 views

OO Design: Algorithm changing State (Information Flow Question)

I have a class Context, which contains an instance of an abstract class State, which has multiple concrete subclasses (this is an implementation of the State Pattern). Each State subclass executes a ...
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0answers
32 views

Adding fields a good use case for EAV? [duplicate]

Is being able to add fields quickly to a system a good use case for EAV? What would be the frequency or number that would justify using an EAV model?
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2answers
119 views

WCF service with methods to fetch data

I'm planning on building a WCF service that will fetch data entities from a Sql Server database. And I'm currently struggling with best practices issues. The thing is that there's a few different ...
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63 views

What's the best pattern to validate a conditional entity? [duplicate]

I'm developing an ASP.NET MVC 5 website and I have a view with a grid. In this grid I have a column which represents an URL property. This url is a link to download some files, but this url should be ...
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0answers
66 views

Whats the best way to implement DataMapper design pater and lazy loading (ghost object)

I'm doing a small project and I wanted to keep it simple to mantain. It is a renting management software. To keep it clean I decided to implement the data mapper patern, to keep the domain objects in ...
4
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4answers
173 views

Using a one-shot class to store not-quite-global variables

I sometimes find myself writing classes (in Python, in my case) that are used like this: MyClass(some_args).go() In other words, there's only one method in the class that any external code would ...
2
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1answer
178 views

Injection, strategies and OO

I'm working on refactoring a project. The business logic looks very much like using the Strategy pattern would be very beneficial, because depending on the values of three properties (let's say age, ...
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6answers
701 views

What are the most used pattern to manage a lot of interconnected parameters?

I recently start to work on an application that drive different measurement device. Before the user start a measure, she sets the parameters of it. Actually, considering all measurements type there ...
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2answers
194 views

A Factory could be replaced by a key on the web.config? How would be the trade-offs of each approach?

The Problem We had a Environment class which would choose whether or not to use a webservice (it was set by a web reference) for our authentication methods by reading the host environment and if it ...
2
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2answers
146 views

Abstract Property In Base Class To Force Programmer To Define It

I'm coding with a state pattern for an embedded device. I have a base/abstract class called State and then each discrete(concrete) state class implements the abstract State Class. In the State Class ...
4
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3answers
158 views

Should dependency inversion be used only with Adapters everywhere?

As I understand the purpose of DI is that I can easily swap a lower level implementation. But it forces the lower level abstraction to be defined inside the higher level. A lower level becomes ...
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0answers
30 views

Graph curve and actual curve plotted on screen implementation patterns

I'm implementing a graph plotter. There are Curve objects, that contains points of actual XY data. When I plot to screen, I need to calculate the XY points on screen, resulting a PlottedCurve. This ...
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2answers
433 views

Class becoming God Object what pattern to use

I am developing Android app and my MainActivity is becoming God Object. By the way native Activity class implementation is some sort of God Object already. The problem is that my activity class is ...
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2answers
179 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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3answers
187 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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1answer
154 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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59 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
131 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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3answers
239 views

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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4answers
401 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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86 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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2answers
264 views

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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2answers
105 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 ...
3
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3answers
169 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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136 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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3answers
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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 ...
2
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1answer
174 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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0answers
47 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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2answers
262 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
173 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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3answers
113 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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2answers
111 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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1answer
66 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 ...
9
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4answers
578 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 ...
1
vote
1answer
133 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 ...
3
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1answer
86 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
210 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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2answers
202 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 ...
3
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3answers
170 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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2answers
57 views

Module based project vs Normal project [closed]

I am writing code on top an established Enterprise application. I see that the application has 4 modules as shown below. -Srk -SrkEJB -SrkUtils -SrkWeb I have gone through the code and I see that ...