DI, dependency-injection, is a design pattern where dependencies (instances of objects, properties) of a component are set through the constructor(s), methods or fields (properties)

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Pooling (Singleton) Objects Against Connection Pools

Given the following scenario A canned enterprise application that maintains its own connection pool A homegrown client application to the enterprise app. This app is built using Spring framework, ...
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Class Interfaces with Multiple Classes and Dependency Injection

NOTE ON QUESTION TITLE: I did not really even know how to phrase the title so if someone can edit and make it more articulate I would really appreciate it. QUESTION: Basically, what I'm trying to do ...
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Data serialization architecture, injection on construction vs. on function call

I am creating a data serialization/deserialization mechanism for essentially a persistent storage object. Due to the variety of systems this mechanism could run on, there needs to be a a variable ...
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Injecting collections as constructor dependencies

We are using constructor dependency injection in our application. Following that approach we inject everything using an injection container so we are able to replace any dependency with a Mock. Some ...
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Factory for creating a singleton instance

We have some legacy code that has a bunch of singletons all over the place (written in C#). The singleton is a fairly "classic" implementation of the pattern: public class SomeSingleton { ...
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Initialize in Field, Constructor, or Argument

If I know what a field will be initialized to, should I initialize it in the field, constructor, or receive it as a parameter? I am asking about best practices. All three options effectively provide ...
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How should dependencies be managed across a modular application?

Let's say that we have a structure like this: Application -- Modules --Module1 -- Controller -- PublicHelper --Module2 -- Controller ...
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Static console object or dependency injection?

For a current project I have created a Console class which wraps up C++'s usual cout, writes output to a file or uses Console::WriteLine depending on the environment. Currently I've setup my code base ...
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Can I use Dependency Injection without breaking Encapsulation?

Here is my Solution and projects: BookStore (solution) BookStore.Coupler (project) Bootstrapper.cs BookStore.Domain (project) CreateBookCommandValidator.cs CompositeValidator.cs IValidate.cs ...
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How to handle “circular dependency” in dependency injection

The title says "Circular Dependency", but it is not the correct wording, because to me the design seems solid. However, consider the following scenario, where the blue parts are given from external ...
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Dependency injection, but not into a controller [migrated]

I recently began experimenting with DI. I am using Unity Ioc to inject an EmailService from by Business Logic Layer into EmailServiceWrapper in the presentation layer which is then instantiated, my ...
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Dependency injection vs dependency lookup in a layered architecture

Given a layered architecture, where the business logic is isolated in a package from all other layers, like persistent storage, user interface, interfaces for various (vendor) remote services, etc, I ...
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Does Refactoring towards Looser Coupling, Smaller Functions, and Separate Classes affect System Performance? (and Should I Care)

In Computer Science field, I have noticed a notable shift in thinking when it comes to programming. The advice as it stands now is write smaller, more testable code refactor existing code into ...
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Transient life time and constructor injection

I'm working on a little light weight Dependency resolver found here https://github.com/AndersMalmgren/DuoCode.SimpleInjector Currently if you do var instance = container.Get<Foo>(); You ...
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What complexity do DI frameworks add?

The currently most upvoted answer to a very recent question states that DI containers are an "enterprise software" pattern, used when the object graph is very large and complex. I suspect that 95% ...
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Should one use Dependency Injection even if the class is used only once? [duplicate]

During a code review I have started having a bit of a dilemma as to whether use dependency injection or not. I would like to hear your thoughts, because this is kind of an ongoing theme and would help ...
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Pick dynamically the right Factory Class with Inversion of Control

I have a TreeView and I want to enable the context menu when clicking with the right mouse button. It is composed by items from different classes, but they all share the same base class. So, I was ...
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Hidden dependencies - why not?

Hidden dependencies: function __construct($dep_registry){ $this->db = $dep_registry->get('db'); $this->request = $dep_registry->get('request'); ... } Not so hidden: function ...
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Dependency Injection with EF - is mapping required?

I'm implementing the Repository pattern with using DI and EF6. I created the database (that inherits from DbContext) object with the Visual Studio wizard ADO.NET Entity Data Model I have a generic ...
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Multiple method calls in the constructor and dependency injection

I was asked to refactor some almost ureadable spaghetti code into object-oriented architecture. I have some doubts regarding a class that I designed. Here is the class' skeleton: require_once ...
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Rich Domain Models, Encapsulation, and the Problem of Constructor Over-Injection

I am refactoring an e-commerce web-application, currently working on the UserBasket class, which will have to handle adding or removing items, changing their quantity, getting total amount, total ...
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Sharing state with dependencies - Object-Oriented Design

Suppose that I define two interfaces below: public interface IReader { void Read(string bookName); } public interface IWriter { void Write(string bookName); } Now I want to implement ...
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What are the best practices to use NHibernate sessions in asp.net (mvc/web api)?

I have the following setup in my project: public class WebApiApplication : System.Web.HttpApplication { public static ISessionFactory SessionFactory { get; private set; } public ...
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Is Functional Programming a viable alternative to dependency injection patterns?

I have recently been reading a book entitled Functional Programming in C# and it occurs to me that the immutable and stateless nature of functional programming accomplishes similar outcomes to ...
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What does the Spring framework do? Should I use it? Why or why not?

So, I'm starting a brand-new project in Java, and am considering using Spring. Why am I considering Spring? Because lots of people tell me I should use Spring! Seriously, any time I've tried to get ...
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Understanding dependency injection

I'm reading about dependency injection (DI). To me, it is a very complicated thing to do, as I was reading it was referencing inversion of control (IoC) as well and such I felt I was going to be in ...
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Where should I put bindings for dependency injection?

I'm new to dependency injection and though I've really liked it so far, I'm not sure where bindings should go. I'm using Guice in Java, so some of what I say might be specific to just Guice. As I see ...
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When NOT to apply Dependency Inversion?

I am currently trying to figure out SOLID. So Dependency inversion means that any two classes should communicate via interfaces, not directly. E.g. if class A has a method, that expects a pointer to ...
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Does merely parameterizing a dependency meet the requirements for Inversion of Control?

When I find a concrete dependency inside an extension method, I have been attempting to remove the (concrete) dependency by parameterising it like so // original implementation public static ...
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Gradual approaches to dependency injection

I'm working on making my classes unit-testable, using dependency injection. But some of these classes have a lot of clients, and I'm not ready to refactor all of them to start passing in the ...
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Is circular Dependency Injection a good practice?

I'm trying the Dependency Injection pattern in some new classes, more specifically in a Transaction System and stumbled into a dilemma. I have a Person class with a create_new_transaction method, and ...
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Is this pattern of optional dependency injection sound? [duplicate]

A lot of the time when working on legacy code bases, I find it hard to move manually created dependencies to the constructor parameters, because of a variety of reasons. Sometimes it's because the ...
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120 views

What is a good practical example demonstrating an architectural advantage in interface dependency injection

I need help (preferably by way of a practical example) to understand why/if the following implementation of IoC/DI (in this case using Ninject) provides an architectural advantage: using (IKernel ...
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How can I avoid tight coupling when practically every decision-logic has to check lots of distributed state?

As the senior developer in our company, I am currently starting to move our commercial php-mysql e-commerce solution (which takes data from a specific ERP-system) from procedural spaghetti-code which ...
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Creating variables in methods/functions

In how far do we create variables in our methods or functions? Do we only create one when we're using the result of the variable more then one time like this? function someFunction(SomeClass ...
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Injecting dependencies (DI) in c++ applications

I am playing with dependency injection, but i am not sure I am doing it right. Especially, I am not sure what should be the correct way to build classes with injected dependencies. Say I have a class ...
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Inject it or create a new instance

suppose i have an interface in some language with two simple methods interface IConverter{ String toString(Object o) Object fromString(String s) } this interface is implemented by many ...
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Difference between spring setter and interface injection?

I know how constructor and setter injection works in spring. Normally I use interfaces instead of classes to inject beans using setter and I consider it as interface injection, but in case of ...
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Are prototype beans with constructor parameters an anti-pattern?

Reading on this, Misko Hevery has said “Newables can ask for other Newables in their constructor, but not for Injectables” Now it appears to me that requesting a prototype be instantiated at run-time ...
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Why would I choose Unity over Autofac [closed]

I'm looking to start a new application and I want to use Dependency Injection. I have a lot of "Microsoft is the only way to go guys" in our shop so of course Unity is the way they wanted to go. ...
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This way I'm writing this code is testable, but is there something wrong with it I'm missing?

I have an interface called IContext. For the purposes of this it doesn't really matter what's it does except the following: T GetService<T>(); What this method does is look at the current DI ...
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Organising data access for dependency injection

In our company we have a relatively long history of database backed applications, but have only just begun experimenting with dependency injection. I am looking for advice about how to convert our ...
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Simple Injector in Onion Layer Architecture

I'm trying to find a good resource, advice, etc in a project I've taken on for myself at work. Background When I started here we had a application that was part MVC part Webform (separate projects ...
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Passing a Context around with dependency injection

In the project I'm working on, I'm using Guice and trying to do as much as possible with Dependency Injection. However, there's one little snag; many of my objects rely on an object Context. This is ...
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What is a relation between Dependency Injection, single instance, and singletons?

I read So Singletons are bad, then what? which was a great explanation of dependency injection as the solution for inversion of control. The asker assumed singleton and single instance were synonyms, ...
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Is the architecture of my project a common one? What's its name?

I am responsible for a software project for a few years now (a Java desktop application, which is mostly event-driven). I started it from scratch, and at the beginning of this project I made some ...
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Is it bad to use DI to inject constructor parameters at runtime?

These are two classes, the first one I inject an instance of type IEngine while the second one I inject owner's name, tickets and engine. Version 1: public class Car { public Car(IEngine ...
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Domain-Driven-Design - external dependencies in the Entity problem

I'd like to start Domain-Driven-Design, but there are several problems I'd like to solve before starting :) Let's imagine I have a Groups and Users and when user wants to join a group, I'm calling ...
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Reducing dependency cycles and reducing coupling

I'm trying to learn how to produce quality object-oriented code and have been studying concepts like SOLID. I'm currently working on an entity-component-process system for a small game engine. ...
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When to use packages or Repositories in Laravel?

I'm a Laravel (PHP) developer, and new with DI, Packages (workbench) and Repositories (Pattern). I want to know about the best concept/methodology for a more flexible design; ie. the project can grow ...