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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18 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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vote
2answers
178 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 ...
9
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3answers
248 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 ...
1
vote
2answers
111 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 ...
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vote
1answer
119 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
...
4
votes
1answer
114 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.
...
2
votes
2answers
156 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
votes
5answers
378 views
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, ...
1
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1answer
136 views
Dependency injection in constructor, method or just use a static class instead? [closed]
What is the best between:
$dispatcher = new Dispatcher($request);
$dispatcher->dispatch();
and
$dispatcher = new Dispatcher();
$dispatcher->dispatch($request);
or even
...
1
vote
1answer
39 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 ...
1
vote
2answers
89 views
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 ...
1
vote
2answers
128 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 ...
5
votes
1answer
331 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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0answers
115 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 ...
2
votes
1answer
52 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 ...
1
vote
2answers
80 views
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 ...
0
votes
0answers
81 views
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 ...
0
votes
1answer
95 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 ...
3
votes
1answer
124 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 ...
5
votes
4answers
421 views
What complexity do DI frameworks add? [on hold]
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% ...
11
votes
3answers
386 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 ...
30
votes
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 ...
1
vote
1answer
95 views
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 ...
1
vote
1answer
109 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 ...
0
votes
1answer
168 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 ...
3
votes
3answers
134 views
Using 2 Constructors: one that injects dependencies and one that instantiates them
I started using TDD for the first time on a project I started recently.
I have a few objects with dependencies and structures that look something like this:
public class MyClass
{
private ...
4
votes
2answers
81 views
How to extend Constructor Injection?
Suppose I have MyClass with a very simple dependency. It uses constructor injection.
public class MyClass : IMyClass
{
private IA A;
public MyClass(IA a)
{
A = a;
}
}
This ...
1
vote
2answers
278 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 ...
5
votes
1answer
435 views
To Repository Or Not To Repository
When I first learnt about Domain Driven Design, I was also introduced to the repository and unit of work patterns that once seemed to be top notch for the cool kids that threw SQL queries like ...
1
vote
2answers
90 views
Dependency injection for request variables in a web application
I'm working a PHP 5.5/MySQL web application.
If a class depends partly on some global GET and POST variables for its members, should I just refer to them directly from within the class, or should I ...
0
votes
0answers
314 views
Spring bean injection into a hibernate validator constraint
I have a controller method like listed below whose argument is annotated with @Valid to validate PasswordChange object using a Hibernate validator @Constraint. Both PasswordChange and a sample ...
0
votes
1answer
69 views
How to design a domain entity that uses a dependency to manage a state field?
I'm new to DDD and IOC/DI and I'm having some trouble figuring out how to design an entity that needs to use a state pattern to manage its status. As the transitions are somewhat complicated, I'm ...
0
votes
1answer
157 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, ...
1
vote
1answer
303 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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vote
2answers
159 views
Dealing with an often occuring dependency that is not related to the class
I'm using view classes for my templating. These view classes often require the Routing class to get URI's from other pages. You could actually say that the Routing should be available to every view ...
1
vote
0answers
113 views
State Pattern Code for embedded device - Dependency Injection of Device Objects in Context and State Classes
I'm wrestling with some code and I think I've finally gotten some state pattern code working with my events.
I've got a simplified system that will work like this:
This is my first go with State ...
6
votes
3answers
218 views
Dependency Injection vs Mixing Levels of Abstraction
I've been reading Clean Code: A Handbook of Agile Software Craftsmanship by Robert C. Martin. One point he makes:
G34 Functions should descend only one level of abstraction
However, I'm ...
1
vote
2answers
143 views
Initialization of objects in a system using dependency injection
This is a follow up question to the following post: Injecting dependencies (DI) in c++ applications
In a system that uses DI, someone, somewhere should be responsible to create the various objects ...
2
votes
2answers
200 views
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 ...
1
vote
2answers
86 views
Logging page/session ID in an inner module
We have a C# ORM module that generates queries. It logs generated queries and other information into the error/trace file. It is used by our web application. Most of our queries are generated ...
2
votes
1answer
171 views
Does Serialization preclude the use of Dependency Injection?
Simple question: I understand that Serialization in C# requires default constructors. This would eliminate the possibility of using Constructor injected DI (which is generally the favored style of DI, ...
3
votes
2answers
683 views
Unit testing, factories, and the Law of Demeter
Here's how my code works. I have an object that represents the current state of something akin to a shopping cart order, stored in a 3rd party shopping API. In my controller code, I want to be able to ...
0
votes
0answers
98 views
Customizing configuration for PHP will Laravel 4 IoC be useful?
This topic has been discussed in this post: Customizing configuration with Dependency Injection
However - I couldn't find one for PHP syntax and since one of the answers was to use a specific ASP.net ...
73
votes
7answers
5k views
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 ...
1
vote
0answers
113 views
Manual dependency injection or abstract factory
We're starting to use dependency injection in a fairly large, interactive program. It's early yet, but I have a feeling that the majority of the objects being injected are going to want runtime data ...
4
votes
2answers
260 views
How to decouple simple factory and default implementation?
I have a simple factory class (FileResources) with static factory methods providing a default implementation (DefaultFileResource).
public final class FileResources {
private FileResources() {}
...
9
votes
3answers
3k views
Which classes should be autowired by Spring (when to use dependency injection)?
I have been using Dependency Injection in Spring for some time now, and I understand how it works and what are some pros and cons of using it. However, when I'm creating a new class I often wonder - ...
1
vote
2answers
92 views
Application settings via constructor injection or ambient context
I am developing an application containing a class which loads application settings from a configuration file.
Settings class:
public sealed class MyAppSettings : IMyAppSettings
{
private ...
1
vote
3answers
168 views
Should I consider loosely-coupling for class methods as well? [duplicate]
I'm a fan of Dependency Injection, however I don't know how much both public and private methods inside a class should be loosely-coupled.
Just to picture it better, when I have both projectId and ...
3
votes
2answers
334 views
Help With Dependency Injection
I am still very confused as to why and when to use Dependency Injection. If anyone could explain maybe using the below example that would be great, any other explanations would be appreciated.
Lets ...
