CODEWITHSUNDEEP
java
SwiftMango
SwiftMango

Reputation: 15294

How can I do injection inside a method body?

I have the following code:

class Foo {
    @Resource(lookup=url)
    private DataSource ds;
}

But the url is dynamic and will be loaded inside a method body:

class Bar {
    public static void main(String[] args) {
        String url = xxx;
        DataSource ds;
        //How to inject the datasource using Annotation?
    }
}

I know how to use context lookup. I wish to know if there is any annotated way to inject.

Upvotes: 3

Views: 2063

Answers (2)

Arsenius
Arsenius

Reputation: 5682

You can use Koin service locator for that purpose. It supports local variables injection inside method.

Upvotes: 0

dkateros
dkateros

Reputation: 1594

Short answer is you can't. There is no way for the code that performs the injection to lookup a local variable of a method. A class field on the other hand is accessible using class inspection methods available in the core java API.

Additionally, an annotation parameter can only be a constant expression.

Upvotes: 3

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