DI vs IOC and Patterns

I need help resolving 2 issues.

After sending this link

http://www.theserverside.com/news/th...hread_id=23358

to a colleague and after pointing out the posts by Martin Fowler himself, this colleague maintains an original position that IoC Dependency Injection are 2 different things. Are they 2 separate things ?

Secondly, when posed with the question what pattern is most at play when you think DI he says Factory. I say Strategy or Template.

Rod Johnson introduces the IoC concept in the context of discussing the Template Method and Strategy patterns. See here (goto page 7):
http://media.techtarget.com/tss/stat...onChapter4.pdf

The real question here is, which pattern mostly resembles DI in action, Factory or Strategy/Template Method (given these 2 choices) ? To elaborate, when Rod Johnson was conceiving the ideas regarding IoC in his original book, was he trying to solve a problem that could be solved with a Factory pattern or was the Factory pattern insufficient for the problem ?

1) Martin Fowler's definition of Inversion of Control includes both Dependency Injection and Service Location. In other words, Dependency Injection is a specific type of IoC.

2) DI != Factory. DI != Strategy. DI relates to both, but mostly resembles the Builder Pattern

Thanks for the reply.
Fowler clearly writes that IoC was renamed to DI. He does not say that DI is a type of IoC. I know this is how it's perceived now(and perhaps rightfully so), but that's not what Fowler wrote. He did write this:

Quote:

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When these containers talk about how they are so useful because they implement "Inversion of Control" I end up very puzzled. Inversion of control is a common characteristic of frameworks, so saying that these lightweight containers are special because they use inversion of control is like saying my car is special because it has wheels.

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As a result I think we need a more specific name for this pattern. Inversion of Control is too generic a term, and thus people find it confusing. As a result with a lot of discussion with various IoC advocates we settled on the name Dependency Injection.

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Those are Fowler's words from the linked article. I'm interested in what Fowler and Johnson intended more so than how it's currently percieved.

I can buy the Builder Pattern argument (perhaps based purely on definition) but I can also buy the Factory Pattern argument. This part of the debate was in the context of Spring's intentions. That's why I referenced Rod Johnson's book. He mentions IoC in the context of the Template Method Pattern and I believe at the time he was writing this he was probably using this pattern to solve a problem in an IoC type of way. I think it's also relevant that he goes on to reference the Strategy Pattern. But I guess only he can really answer this.

Quote:

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Originally Posted by dsmith

Thanks for the reply.
Fowler clearly writes that IoC was renamed to DI. He does not say that DI is a type of IoC. I know this is how it's perceived now(and perhaps rightfully so), but that's not what Fowler wrote. He did write this:

Quote:

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As a result I think we need a more specific name for this pattern. Inversion of Control is too generic a term, and thus people find it confusing. As a result with a lot of discussion with various IoC advocates we settled on the name Dependency Injection.

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Those are Fowler's words from the linked article. I'm interested in what Fowler and Johnson intended more so than how it's currently percieved.
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He also says:

Quote:

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In this article I dig into how this pattern works, under the more specific name of "Dependency Injection", and contrast it with the Service Locator alternative.

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Doesn't that imply that "Dependency Injection" is a more specific type of "Inversion of Control?" In the end, it's all just terminology.

(Martin Fowler is a self proclaimed compulsive Neologist. He speaks about IoC vs. DI. The term DI was his invention, and he talks a bit about why he created it)

Quote:

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Originally Posted by Solomon

He also says:



Doesn't that imply that "Dependency Injection" is a more specific type of "Inversion of Control?" In the end, it's all just terminology.

(Martin Fowler is a self proclaimed compulsive Neologist. He speaks about IoC vs. DI. The term DI was his invention, and he talks a bit about why he created it)

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No, it doesn't. It's pretty clear now, DI = IoC.