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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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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963 views

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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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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416 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 ...
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374 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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335 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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40 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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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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182 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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57 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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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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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 ...
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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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803 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
39 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 ...
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182 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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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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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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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 & ...
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58 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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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 ...
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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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3answers
681 views

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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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 ...
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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% ...
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1answer
155 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 ...
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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
90 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 ...
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2answers
190 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 ...
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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 ...
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242 views

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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1answer
357 views

Decoupling when constructors have non-contractual parameters

By non-contractual parameters, I mean parameters that are not interfaces or service dependencies, something like class Person(string name). I am writing a webpage scraping application, and so far ...
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417 views

Recommendations on integrating DI/IoC container into an existing application

I am now faced with integrating an inversion of control (IoC) container into an existing application, and I'm looking for some recommendations on how that can most easily be accomplished with the ...
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1answer
53 views

Are the required parameters of a function called dependencies?

I'm studying dependency injection and I want to know if required function parameters can be considered dependencies. I'd just like to make sure before I go around referring to them dependencies and ...
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How should one implement the dependency-injection for a geocoding client that aggregates different coordinate provider implementations?

I am new to DI and I would like to know how DI might be used to help resolve this problem. If I have an ILatLongLocation which implements a Latitude and Longitude, then given two of these I can ...
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Save database changes in service layer or controller mvc .net

I have recently been using a service layer to abstract away alot of the business logic of my application. However I've come into an issue where I'm not sure what is best practice on doing the actual ...
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1answer
143 views

How can I use guice to replace code dependent on service locator implementation?

Consider I have a service called FileSystem, and that this FileSystem is used by various classes throughout the application. Typically, the service is acquired via some static class method ...
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1answer
169 views

Showing a View from another View in MVP

This question is regarding MVP triads. Lets say I have two triads and first one has View1, Mode1 and Presenter1. Second triad has View2, Model2 and Presenter2. Now what I trying to do is, I just want ...
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3answers
398 views

Do dependency injection frameworks pose a dependency risk?

I have been refactoring an existing system to use dependency injection, and that work has been going smoothly. After a while I noticed that a large number of in-house libraries became dependent upon ...
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1answer
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What are Dependency Injections and why are they useful? [closed]

I have heard of ninject and I have to build a lot of apps that have to integrate with other tools. SO i was wondering what this was and how it is used.
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3answers
3k views

How does dependecy injection increase coupling?

On the Wikipedia page on dependency injection, the disadvantages section tells us this: Dependency injection increases coupling by requiring the user of a subsystem to provide for the needs of ...
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How to properly handle conditional dependencies in a factory?

Let's say you have a string $action run-time, that specifies which type of $object needs to be created: $dbobject, $memcacheobject, $fileobject, $xmlobject, etc. Assume also, that creation of an ...
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172 views

Passing a dependency to a controller class

I'm looking for an approach to the following problem: I have a reusable library. It contains a controller class, in the MVC sense. Let's say it's called UserAdministrationController, and it's for ...
2
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1answer
170 views

How to handle passing multiple dependencies in a module hierarchy

So I have my application consisting of a number of modules in a module hierarchy. Furthermore let's also assume each module is a class and we have a tree of classes where the classes at the top are ...
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204 views

Applying DDD to a simple app with a configuration twist

I’m using the light-weight PHP Fat-Free Framework as a base to form a simple MVC based app with DDD philosophy for the Model layer. I’m aware that DDD is most suitable or enterprise solutions and that ...