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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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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3answers
452 views

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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1answer
43 views

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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1answer
383 views

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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6answers
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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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1answer
119 views

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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680 views

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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1answer
128 views

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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0answers
64 views

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 ...
0
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1answer
277 views

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, ...
0
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1answer
95 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 ...
2
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2answers
180 views

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 ...
3
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1answer
102 views

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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3answers
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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 ...
2
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1answer
122 views

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 ...
3
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1answer
9k views

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 ...
0
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0answers
63 views

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 ...
0
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2answers
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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. ...
12
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4answers
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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 ...
2
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1answer
466 views

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 ...
0
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1answer
179 views

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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2answers
135 views

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? For example, where should I initialize an ArrayList? Initialized in ...
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1answer
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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 ...
0
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1answer
85 views

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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3answers
639 views

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 ...
0
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4answers
429 views

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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2answers
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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 ...
4
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3answers
250 views

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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1answer
210 views

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 ...
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1answer
70 views

How to manage coupling in model classes

I'm doing a class diagram for a game project, but I'm stuck on a coupling problem. Context The projet is a turn-based game. Two users are playing. They've got units on a map. They play until 1 ...
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5answers
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What does Dependency Injection mean by saying it can inject on runtime?

I understand that the dependency injection is something done by coding and its all done at compile time. And that Dependency injection coding is easily done now by helper tools like Ninject. However ...
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0answers
43 views

How to clean composition root from anything other than object construction?

I'm doing poor man's DI (manual injection) in my application. My (pseudo-) composition root looks something like this: var connectionSettings = new Settings(SqlParameters) var dataLoader = new ...
0
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1answer
167 views

IOC Between Presentation and Infrastructure Layer

Question: I would like to set forth dependency mapping from a *.config file from a project that has no reference to the project that contains the concrete class. Scenario: I'll be using terms from ...
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4answers
863 views

Acceptable placement of the composition root using dependency injection (DI) and inversion of control (IoC) containers

I've read in several sources including Mark Seemann's 'Ploeh' blog about how the appropriate placement of the composition root of an IoC container is as close as possible to the entry point of an ...
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1answer
96 views

Issues about static injection in Spring?

I use spring-boot with spring xml in my project. I wrapper the DAOs in a DataAccessService class to serve as a DB service layer, both the service and the DAOs are injected in spring xml and used by ...
3
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2answers
204 views

IoC as service locator

I have been wondering for quite some time on some issues while using dependency injection: In a layered application, I normally inject repositories into the application service using constructor ...
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3answers
217 views

Why does dependency injection encourage collaboration to be exposed via constructors?

The general approach to DI that I see in answers like So Singletons are bad, then what? encourages business objects that collaborate with other objects to (a) not directly create those instances and ...
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1answer
201 views

C# Dependency Injection Placement

This is my first time using Unity so bear with me for a moment. I have a sample Visual Studio 2012 project with 4 projects (but only two of these projects will be used with Unity). This is the ...
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0answers
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Am I following a good design thought process? Is the Abp framework overkill?

As I finish one project and start another, I have a small time window to come up with an architecture for the new. I am coming from the following design: Web applicationReceives domain models & ...
0
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1answer
73 views

Value Object: static factory or assisted injection?

First let assume that everybody agree that there is nothing wrong with injecting some value object into injectable object such as service. Indeed, a service can get another service injected, but could ...
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2answers
243 views

when using dependency injection, should I always pass an interface

When using depending injection, you generally pass everything around as an interface (perhaps with the exception of primitives and strings). That allows you to easily chance the behavior, without ...
14
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3answers
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I get dependency injection, but can someone help me understand the need for an IoC container?

I apologize if this seems like yet another repeat of the question, but every time I find an article regarding the topic, it mostly just talks about what DI is. So, I get DI, but I'm trying to ...
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2answers
167 views

Why do IoC containers provide public Resolve method(s)?

In my opinion it just inverses the inversion and could make new users (including myself) make incorrect assumptions about using IoC containers. It can be used for the Service Locator (anti-)pattern ...
5
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4answers
460 views

What complexity do DI frameworks add? [closed]

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% ...
1
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1answer
177 views

Should the Presenter depend on the View or the vice versa?

So far, I have used the MVP architecture pattern a few times. Every now and then, I wonder whether my Presenter should depend on my View or vice versa, that is the View depends on my Presenter. NOTE ...
18
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6answers
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Dependency injection ; good practices to reduce boilerplate code

I have a simple question, and I'm not even sure it has an answer but let's try. I'm coding in C++, and using dependancy injection to avoid global state. This works quite well, and I don't run in ...
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1answer
149 views

Ninject/DI: How to correctly pass initialisation data to injected type at runtime

I have the following two classes: public class StoreService : IStoreService { private IEmailService _emailService; public StoreService(IEmailService emailService) { _emailService ...
2
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2answers
227 views

Dependency Injection: where to store dependencies used by only one method?

I am developing a project integrated with Dependency Injection (just for reference, I'm using Unity). The problem is that I have some Manager classes with several methods and in many cases I have ...
4
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5answers
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Questioning one of the arguments for dependency injection: Why is creating an object graph hard?

Dependency injection frameworks like Google Guice give the following motivation for their usage (source): To construct an object, you first build its dependencies. But to build each dependency, ...
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How best to construct our test subjects in unit tests?

Some of our business logic classes require quite a few dependencies (in our case 7-10). As such when we come to unit test these the creation become quite complex. In most tests these dependencies are ...