Member Injectors & Inject Methods & Inheritance

[dlemures]

There are some issues regarding the Methods Injects, overrides and inheritance:

class A {
    @Inject C c;

    @Inject
    public void init() {
        .
    }
}

class B extends A {
    @Inject D d;

    @Override
    public void init() {
        .
    }
}

1) Initialization should use the order: First inject @Inject annotated fields, then call @Inject annotated methods.

However, for the example if we inject B, the order is:

C (A field) -> init (B METHOD) -> D (B field)

Which is wrong. Inside its init method, B can assume all fields are injected, and this didn't happen yet.

2) If B was like this:

class B extends A {
    @Override
    public void init() {
        .
    }
}

The member injector would not be generated, but we need it. We could add @Injectto init, but @Override is not mandatory and if it is omitted, init would be called twice during initialization.

3) Let's imaging now a slightly different example:

class A {
    @Inject C c;

    public void init() {
        .
    }
}

class B extends A {
    @Inject D d;

    @Override
    @Inject
    public void init() {
        .
    }
}

Will init be called when injecting B using its member injector?

[dlemures]

This is an invalid use case.
Methods that are inject annotated should not be overriden.

1. They are similar to "constructors", constructor cannot be overriden.
2. They make it difficult for the user to understand what's going on.
3. From a technical point of view, it is not possible for TP to find out all overrides.

Thus, we discourage to override any inject annotated method. To make it clearer a warning is displayed whenever a inject annotated method has PUBLIC or PROTECTED visibility:

@Inject annotated methods should have protect visibility...

[dlemures]

PR merged: #160