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

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Should you register other services in ViewModelLocator in MVVM light?

I'm new to MVVM Light and SimpleIoC. My question is, should all the registration of view models and other services be done in the ViewModelLocator class? Or should ViewModelLocator be used only for ...
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36 views

What is the best way to initialize a child's reference to its parent? [duplicate]

I'm developing an object model that has lots of different parent/child classes. Each child object has a reference to its parent object. I can think of (and have tried) several ways to initialize the ...
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155 views

Should I have an object as attribute or primitive id? [duplicate]

I am wondering which principle should I use. Here is my situation. I have a class named TravelOffer. This class looks like this: public class TravelOffer { private final long id; private ...
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115 views

Controllers passing Request objects to backend logic that forward Request data: Good or Bad?

Currently working on a server-side front-end Scala Play app that does a lot of grabbing of HTML snippets and JSON from many other web apps before piecing everything together and sending it in a ...
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241 views

Does this diagram give a good representation of the MVVM pattern?

I am having a really hard time understanding the basic structure of the Model, View, View Model pattern. I have honestly been pretty ignorant of design pattern conventions until recently. My formal ...
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151 views

Pitfalls of combining dependant traits and exceptions in same file as interface in php

What are the potential pitfalls of combining related class like objects (interfaces, traits, custom exceptions) in the same source file? For code reuse and only loading what I need I always separate ...
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265 views

Best Practices For Temporary Scripts (Python)

I am running two separate programs which are similar enough that they share a lot of code. I run these programs often and after I evaluate the output. This is a very fluid process and everytime is ...
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2answers
489 views

Confused about javascript module pattern implementation

I have a class written on a project I'm working on that I've been told is using the module pattern, but it's doing things a little differently than the examples I've seen. It basically takes this ...
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58 views

Extending database model of ORM in subproject

I have a maven project which contains some entities which are stored in a database. The purpose of this project is to manage personal information, users, locations, etc. This project can work on its ...
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2answers
460 views

Effective Repository in C# - Where to put methods?

I'm trying to build a new application using the Repository pattern for the first time and I'm a little confused about using a Repository. Suppose I have the following classes: public class Ticket { ...
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54 views

Modeling Associations

I am working on the design phase of a paper folding project. I have a few queries in this. Part of the problem statement says " A web can contain one or more ribbons in it. It can also contain a ...
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266 views

Encapsulate multiple properties into a single class to use as a custom DependencyProperty

My application is a WPF project implemented in C# .NET (4.5) using an MVVM architecture with no code-behind in the View. In order to eliminate the coupling between the View and the ViewModel I'm ...
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2answers
333 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 ...
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14 views

Select design pattern - user stage [duplicate]

I'm struggling to point a finger into the right design pattern. I have a web site which user can register and interact with the system. I want to add the following abilities to a user: Each user ...
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1answer
157 views

Why is the “app” folder now a (more) common pattern in web projects?

It might be related to the Yeoman project, or they might have adopted this from somewhere else, but it seems to be the default for all of their generators. Aside from Yeoman generators I've also ...
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132 views

How to cleanly write a multi step process with user feedback and multiple callback

When you have some process that has several steps and you multiple entry points the code gets ugly pretty fast. I encountered this with Facebook integration in my mobile app: User wants to share ...
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116 views

does class reference itself static anti pattern in prism

I have an application and my desing approach look like this: class Manager { public int State; static Manager _instance = null; public static Manager Instance { get { return ...
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1answer
314 views

Does my use of the strategy pattern violate the fundamental MVC pattern in iOS?

I'm about to use the 'strategy' pattern in my iOS app, but feel like my approach violates the somehow fundamental MVC pattern. My app is displaying visual "stories", and a Story consists (i.e. has ...
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1answer
220 views

Can this argument be enough?

We have two C++ classes named Important and Small The class Small use a few methods and attributes from the class Important, but not all. Since our application is performance critical, instead of ...
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1answer
554 views

Implementing a strategy pattern with dependency injection

Okay, so the goal here is to implement a strategy pattern that can be tested using any sort of automated testing tool. I've been struggling with this problem conceptually for a few weeks now and I ...
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1answer
61 views

Is it fine for a class that creates objects to delegate them?

I have a large list of intercommunicating components; so I decided to have one class create all of them and then subsequently delegate them to other classes to facilitate finer tweaking and wiring ...
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0answers
104 views

Looking for design pattern to represent shared state in music sequencer

I like to give lots of context, but also to state the basic question up top as concisely as possible. Feel free to read a little or a lot. I'm working on a music sequencer, and have been happy so far ...
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69 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
196 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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96 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 ...
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1answer
279 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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334 views

Which interface allows you to use a design pattern that is characteristically changed with the instantiation of objects?

I can't find my answer to this question: Which interface allows you to use a design pattern that is characteristically changed with the instantiation of objects? I found something related to ...
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1answer
170 views

Several interdependent models, each with several data sources — how to avoid hell and nightmare

I'm currently working on a project that requires a complicated model structure and I'm struggling with picking the right architecture. First of all, there are several interdependent models. Change in ...
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1answer
332 views

Design pattern for configuring objects

Context In a Cocoa application I am developing, I need to load a data model that is defined in plist files. So, I have something like: root (Array) ---- item (Dictionary) -------- name : "objects" ...
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1answer
169 views

Boolean properties in Class A control availability of members in Class B: Design Pattern?

Given the following code: class AnimalDescriptor { String species; boolean hasLegs; boolean hasTeeth; boolean hasHair; public AnimalDescriptor(String species, boolean hasLegs, ...
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177 views

Algorithms or patterns for a linked question and answer cost calculator

I've been asked to build an online calculator in PHP (and the Laravel framework). It will take the answers to a series of questions to estimate the cost of a home extension. For example, a couple of ...
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714 views

Syncing client and server CRUD operations using json and php

I'm working on some code to sync the state of models between client (being a javascript application) and server. Often I end up writing redundant code to track the client and server objects so I can ...
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1answer
93 views

How are the forwarding of requests normally managed in the Chain of Responsibilty pattern? [closed]

I was just experimenting with the Chain of responsibility design pattern, implementing my own version. I'm currently reading Design Patterns, but I'm not really sure whether DP tells to stop the ...
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293 views

How should Object Model wrapper classes behave when underlying objects are deleted?

I'm currently building an object model library for use in a project. It wraps our internal concepts - Servers, Folders, Items - in an object hierarchy (IFolder, IItem, etc), and we have several ...
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100 views

Design decision for implementing the cache re-arrange logic

I'm working on a webapp which has an existing framework to cache values from the database. I have a requirement which needs multiple values from the database and the values have to be ...
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1answer
327 views

Design pattern for locking asynchronous operations in Objective-C

I'm writing my first Objective-C Class. It's responsible for interaction with an HTTP SSO authentication service. The process requires multiple HTTP transactions in order to complete. The Class acts ...
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0answers
214 views

Do multiple 'helper' classes conflict with the accepted Apple design scheme?

I have a social location based application and I'm in a bit of design conflict that I can't seem to solve or find good information on. Realizing that I have multiple controllers that will similarly ...
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1answer
136 views

Architecture for writing add-ins for closed-source software

currently I'm designing an add-in for the modelling tool Enterprise Architect. The general architecture is shown in the picture below. Basically every action where the add-in can react to is ...
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330 views

Online stores service design [duplicate]

I am designing an online store service app with rails. Everyone who wants to make his/her own store can do it with this app by just signing up and choosing a domain. I want to make it as SaaS as it ...
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1answer
311 views

iOS object instance accessible from three separate classes, or load 3 nib files with one class?

I've got three nib files in my project, each of which is driven by its own class (.h and .m files). Each nib has a stylized design with a full screen background image and a few overlay images acting ...
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1answer
4k views

Implementing a ILogger interface to log data

I have a need to write data to file in one of my classes. Obviously I will pass an interface into my class to decouple it. I was thinking this interface will be used for testing and also in other ...
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1answer
300 views

Designing classes containing the same objects but different amount of them

I am creating a main object, MACHINE, which will contain a diversity of several other objects -- AXIS, AMPLIFIER, ENDEFFECTOR, etc. The number of contained objects will vary depending on the MACHINE ...
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1answer
136 views

Why use the Singleton pattern over class functions and fields? [duplicate]

I'm going to start by saying that I understand that programming in mostly class functions and variables can be harmful to object-orientation, and that most of the time an instance is preferred. I'll ...
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2answers
2k views

What are the current problems involved in software engineering programming patterns? [closed]

can someone suggest me the current problems in software engineering and the research links for it? i have some knowledge on MVVM being a pattern but i would like to know more about others and also ...
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1answer
87 views

How to compute data for charting?

I'm building a charting component that displays data directly from the raw data records. It should be able to filter data (subset) and then perform some rudimentry maths on the data (sum, avg, etc). ...
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1answer
192 views

Geographically Distributed (Data & App) Architecture

Is there any design patterns (or best practices) for implementing a geographically distributed system (mostly a database)? Description: There is a network of warehouses and a central office. Now I ...
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3answers
411 views

Which Design Pattern Is Best Suited?

I have been studying Design Patterns and I am looking to implement them into my latest project. I am working on a Windows Service that regularly checks a database table for a new entry. Depending on ...
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votes
3answers
119 views

What design pattern is this? [duplicate]

I'm struggling to come up with the name of a design pattern that I need to write about. I've been lead to think it was abstraction but apparently not. Let's say I had a driver class which has a Drive ...
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2answers
487 views

Generics vs IoC [closed]

One of the "Service Locator" pattern drawbacks is that a caller can be misleaded about dependencies of a callee. Ok, but what if I put dependencies as generic parameters at a class level: class ...
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3answers
179 views

How to design a solution that needs dynamism using Inheritance [closed]

I have below code/classes/interfaces: An Interface: public interface Animal<A extends Animal<A>>{ void fight(A otherAnimal); } 2.Tiger class which is implementing Animal ...