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)

learn more… | top users | synonyms

2
votes
3answers
291 views

Dependency injection and ease of use

I'm writing a handy library (we'll call it Thinger) that goes off and fetches an XML document, does some X-Path query on it and does something helpful with the result of that. (What I'm actually doing ...
1
vote
0answers
232 views

Single write, multiple read of stateful objects

Scenario: One data input feed (call this Source) Multiple objects (call these Layer1) read this Source, and analyze the feed. This analysis is stateful. Layer1 objects have configuration parameters. ...
0
votes
1answer
117 views

How to 'convert' a Static Access style project to IoC/DI style?

Are there any best approaches for refactoring a programming project that has previously been written with the static reference anti-pattern (the majority of classes refer at some point to a static ...
2
votes
1answer
291 views

Is it a bad design to specify default bindings when using Inversion of Control (IOC) containers and dependency injection (DI)?

I'm using Ninject, but this is not a Ninject-specific question. I'm wondering if the advanced and flexible capabilities of the IoC container are giving me enough rope to hang myself with a bad ...
8
votes
4answers
1k 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 ...
9
votes
2answers
1k views

What's the practical difference between the styles of dependency injection?

I'm new to dependency injection and I have a few questions about which style I shouldI use in my applications. I've just read Inversion of Control Containers and the Dependency Injection pattern by ...
37
votes
6answers
9k views

Should I use Dependency Injection or static factories?

When designing a system I am often faced with the problem of having a bunch of modules (logging, database acces, etc) being used by the other modules. The question is, how do I go about providing ...
6
votes
5answers
420 views

When to use DI and when to create yourself in Java

I've a decent amount of OOP with various languages but am pretty new to Java. I'm reading through a lot of tutorials where large numbers of objects are created within the code of a class, and I'm ...
5
votes
1answer
842 views

Explanation of Object-parameter-coupling as mentioned in Code Complete book

I have been reading up on the seminal and excellent book Code Complete. It discusses about the various kinds of couplings that can happen between modules(which may be classes as well as methods): ...
5
votes
2answers
1k views

Dependency Injection - Dependency Chain Pattern

On my last large project, I used dependency injection really heavily. I started out using constructor injection but even two or three dependencies resulted in really ugly code. public MyClass( ...
0
votes
2answers
2k views

1 Interface 2 Implementations and an EJB exception

In my JavaEE project I have an interface like this: @Local public interface DataAccess { ... } And two stateless beans implementing it: @Stateless public class DataAccess_Online implements ...
8
votes
4answers
7k views

How to use Dependency Injection in conjunction with the Factory pattern

Consider a module that is responsible for parsing files of any given type. I am thinking of using the strategy pattern to tackle this problem as I have already explained over here. Please refer to the ...
1
vote
0answers
540 views

ASP.NET Mvc3 - application/request lifetime and dependency injection

I thought of asking on SO, but it seems this is more of a "concept" type question than a "problem" type question. If it needs to be moved, please do so. Anyway, I'm having a tough time finding ...
4
votes
3answers
1k views

Is it a good idea to register views and view models as singletons in an IOC container?

I understand the benefits of injecting dependencies into objects, but have not found much guidance on the types of objects to inject and when to make them singletons. If we take as as example an ...
4
votes
2answers
1k views

How to program object-oriented with a DI framework? [duplicate]

Possible Duplicate: Does “Inversion of Control” promote “Anemic Domain Model”? My impression is that projects using a DI framework like Spring or Guice tend to lose their object orientation ...
2
votes
2answers
3k views

Unit of work/repository pattern with dependency injection advice

I'm developing a series of repository classes and a UnitOfWork class (plus its IUnitOfWork interface of course). I'm using Castle Windsor, which injects dependencies via constructors. My business ...
3
votes
2answers
413 views

Desktop application, dependency injection

I am thinking of applying a real dependency injection library to my toy C#/GTK# desktop application. I chose NInject, but I think this is irrelevant to my question. There is a database object, a main ...
19
votes
3answers
17k views

What is constructor injection?

I have been looking at the terms constructor injection and dependency injection while going through articles on (Service locator) design patterns. When I googled about constructor injection, I got ...
3
votes
4answers
410 views

Representing complex object dependencies

I have several classes with a reasonably complex (but acyclic) dependency graph. All the dependencies are of the form: class X instance contains an attribute of class Y. All such attributes are set ...
0
votes
1answer
345 views

What are some books that explain low level stuff like com interfaces, dll injection etc? [closed]

What are some books that explain low level stuff like com interfaces, dll injection etc? Basically low level windows programming. Searching on amazon gives me hacking books/10+ year old books which is ...
4
votes
6answers
1k views

How to do dependency Injection and conditional object creation based on type?

I have a service endpoint initialized using DI. It is of the following style. This end point is used across the app. public class CustomerService : ICustomerService { private IValidationService ...
8
votes
5answers
619 views

How to TDD test that objects are being added to a collection if the collection is private?

Assume that I planned to write a class that worked something like this: public class GameCharacter { private Collection<CharacterEffect> _collection; public void Add(CharacterEffect e) ...
4
votes
4answers
375 views

Are injectable classes allowed to have constructor parameters in DI?

Given the following code: class ClientClass{ public function print(){ //some code to calculate $inputString $parser= new Parser($inputString); $result= ...
5
votes
2answers
376 views

Can higher-order functions in FP be interpreted as some kind of dependency injection?

According to this article, in object-oriented programming / design dependency injection involves a dependent consumer, a declaration of a component's dependencies, defined as interface contracts, an ...
2
votes
2answers
296 views

Is functional intellisense and code browsing more beneficial than the use of dependency injection containers

This question is really based on PHP, but could be valid for other dynamically typed, interpreted languages and specifically the methods of generating code insight and object browsing in development ...
4
votes
2answers
638 views

DI and hypothetical readonly setters in C#

Sometimes I would like to declare a property like this: public string Name { get; readonly set; } I am wondering if anyone sees a reason why such a syntax shouldn't exist. I believe that because it ...
4
votes
3answers
269 views

In dependency injection, is there a simple name for the counterpart of the injected object? [closed]

In tutorials and books, I have never seen a single word describing the object that the injected object is injected into. Instead, other terms are used, like "injection point" which don't denote the ...
4
votes
2answers
258 views

Dependency injection and IOC containers in a closed project

Does it make sense to assemble my project with dependency injection containers if I am the only one who will use the code of that project? The question came up when I read this IOC Article ...
6
votes
2answers
436 views

How to use DI and DI containers

I am building a small PHP mvc framework (yes, yet another one), mostly for learning purposes, and I am trying to do it the right way, so I'd like to use a DI container, but I am not asking which one ...
13
votes
1answer
4k views

Dependency Injection/IoC container practices when writing frameworks

I've used various IoC containers (Castle.Windsor, Autofac, MEF, etc) for .Net in a number of projects. I have found they tend to be frequently abused and encourage a number of bad practices. Are ...
9
votes
2answers
7k views

Dependency injection with n-tier Entity Framework solution

I am currently designing an n-tier solution which is using Entity Framework 5 (.net 4) as its data access strategy, but am concerned about how to incorporate dependency injection to make it testable / ...
3
votes
1answer
13k 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 ...
7
votes
1answer
565 views

Who should initialize dependencies in a TDD application?

I'm trying to learn implementing TDD with mocking/fake objects. One of the questions I have is how to initialize a dependency in an application which implements TDD? An example from this article ...
13
votes
5answers
1k views

Does following TDD inevitably lead to DI?

I learned to do Test Driven Development (TDD), Dependency Injection (DI) and Inversion of Control (IoC) all at the same time. When I write code using TDD I always end up using DI in my class's ...
4
votes
1answer
330 views

DI: Can a stable dependency have a volatile dependency?

I've recently been reading through Mark Seemann's Dependency Injection in .NET and have been attempting to apply some of what I've learned in a new project I'm working on, and I'm stumped on a ...
19
votes
6answers
8k views

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 ...
3
votes
2answers
289 views

When is using DI and optionally a IoC framework a step too far?

Consider a logging system - used absolutely everywhere in your codebase. (note - logging is just an example, don't take it too literally and point me at your favourite logging system). public ...
2
votes
2answers
2k views

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 ...
0
votes
1answer
1k views

How to make Ninject inject an MVC view model?

How do I configure Ninject so it injects an instance in a view model? PS. It is an abstracted service to help with validation, so I am not trying to burden the model with too much responsibilities.
8
votes
3answers
2k views

IValidatableObject vs Single Responsibility

I like the extnesibility point of MVC, allowing view models to implement IValidatableObject, and add custom validation. I try to keep my Controllers lean, having this code be the only validation ...
5
votes
2answers
2k views

Is dependency injection by hand a better alternative to composition and polymorphism?

First, I'm an entry level programmer; In fact, I'm finishing an A.S. degree with a final capstone project over the summer. In my new job, when there isn't some project for me to do (they're waiting ...
91
votes
18answers
10k views

Dependency injection: How to sell it

Let it be known that I am a big fan of dependency injection (DI) and automated testing. I could talk all day about it. Background Recently, our team just got this big project that is to built from ...
1
vote
2answers
372 views

Trying to grasp the idea of DI/Unity and possibly apply it to our simple application

Our app basically is a few forms that are filled out by people.. Then these forms are validated and reviewed and reports are created.. So I was thinking about DI and messing with a simple example of ...
6
votes
4answers
994 views

Should injecting dependencies be done in the ctor or per method?

Consider: public class CtorInjectionExample { public CtorInjectionExample(ISomeRepository SomeRepositoryIn, IOtherRepository OtherRepositoryIn) { this._someRepository = ...
1
vote
3answers
361 views

How I can hide dependencies from my Services?

Here's a service abstraction that I am working on : public abstract class Service { public ILogger Logger{get;set;} public IQueryManager QueryManager{get;set;} public ICommandManager ...
16
votes
3answers
5k views

Interception vs Injection: a framework architecture decision

There's this framework that I'm helping to design. There are some common tasks that should be done using some common components : Logging, Caching and raising events in particular. I am not sure if ...
1
vote
1answer
418 views

Are service locators really that bad?

People say Service Locators are bad because they expose the dependencies in some random method from the class (and not in the constructor's arguments like it should): class A{ function F(){ ...
60
votes
5answers
13k views

When is it not appropriate to use the dependency injection pattern?

Since learning (and loving) automated testing I have found myself using the dependency injection pattern in almost every project. Is it always appropriate to use this pattern when working with ...
8
votes
3answers
677 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 ...
4
votes
1answer
8k views

How do I use PowerMock / Mockito / EasyMock to use a mocked object for dependency injection?

I have an AuthenticationManager.authenticate(username,password) method that gets called in someMethod of a SomeService under test. The AuthenticationManager is injected into SomeService: @Component ...