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How to do ContextInjectionFactory.make with paramatrized constructor? [message #1002456]

Fri, 18 January 2013 11:10

Eclipse User

I have a widget named TableToolbar which has a parametrized constructor.

class TableToolbar{

@Inject 
MyData data;

public TableToolbar(Composite parentComposite) {
func(data);
...
}

I would like to Inject the data from IEclipseContext into it, before starting the constructor.
This I usually do with

ContextInjectionFactory.make(TableToolbar, eclipseContext);

Now I have a specific Composite, which I need to pass a specific Composite to the TableToolbar constructor.
Is it possible?

P.S.
I can not inject the data later by

TableToolbar tableToolbar= new TableToolbar(composite);
ContextInjectionFactory.inject(tableToolbar, context);

because the injected data are needed inside the constructor.

Re: How to do ContextInjectionFactory.make with paramatrized constructor? [message #1002555 is a reply to message #1002456]

Fri, 18 January 2013 15:38

Eclipse User

How about create a child context and set your parentComposite there, then use it to make the object

c2 = context.createChild();
c2.set( Composite.class, myParentComposite );
ContextInjectionFactory.make(TableToolbar.class, c2);

Frank

Re: How to do ContextInjectionFactory.make with paramatrized constructor? [message #1002597 is a reply to message #1002555]

Fri, 18 January 2013 17:52

Eclipse User

That's correct still he'll fail because workflow is this:

a) run constructor code
b) do field injection
c) do method injection
d) run @PostConstruct

Hence he'll has to have MyData as an constructor argument.

Tom

Am 18.01.13 21:38, schrieb Frank Benoit:
> How about create a child context and set your parentComposite there,
> then use it to make the object
>
>
> c2 = context.createChild();
> c2.set( Composite.class, myParentComposite );
> ContextInjectionFactory.make(TableToolbar.class, c2);
>
>
> Frank

Re: How to do ContextInjectionFactory.make with paramatrized constructor? [message #1002937 is a reply to message #1002597]

Sat, 19 January 2013 17:27

Eclipse User

This doesn't make sense because you can not expect a (non-static)field of an object to be set before its constructor returns (i.e. the object is created). First you have to have an object (which you don't have until the constructor returns) and then set its fields. DI can't break these rules.

Re: How to do ContextInjectionFactory.make with paramatrized constructor? [message #1003444 is a reply to message #1002937]

Mon, 21 January 2013 04:02

Eclipse User

For now I had to move all the constructor logic into a separate method init().

Now I can manually create the Object, with a concrete composite as parameter.
Then I Inject the missing fields, by using the ContextInjectionFactory
Then I call the init(), which contains all the constructor logic using injected variables.

With other words I am changing the lifecycle, to do the injection, before calling the constructor.

class TableToolbar{

@Inject 
MyData data;

public TableToolbar(Composite parentComposite) {}

public void init(){
 func(data);
 ...
}

        TableToolbar toolbar = new TableToolbar(containerTop);
        ContextInjectionFactory.inject(toolbar, context);
        toolbar.init();

Re: How to do ContextInjectionFactory.make with paramatrized constructor? [message #1003461 is a reply to message #1003444]

Mon, 21 January 2013 04:35

Eclipse User

I didn't look at the code but you can not do any injection except constructor argument injection before the constructor returns.

Why don't you use @PostConstruct? Remove the @Inject from data and, run your constructor and add a method :

@PostConstruct
public void init(MyData data){
this.data=data;
func(data);
}

and you don't need CIF or manually call init.

Re: How to do ContextInjectionFactory.make with paramatrized constructor? [message #1003557 is a reply to message #1003461]

Mon, 21 January 2013 09:10

Eclipse User

Thnx Sopot, now my code looks as following:

class TableToolbar{

@Inject 
MyData data;

public TableToolbar(Composite parentComposite) {}

@PostConstruct
public void init(){
 func(data);
 ...
}


TableToolbar toolbar = new TableToolbar(containerTop);
ContextInjectionFactory.inject(toolbar, context); //calls @PostConstruct annotated method

I still have to inject manually, because I would like to create the TableToolbar myselfe. It makes the code more understandable, than using Tom's version, with a child container:

c2 = context.createChild();
c2.set( Composite.class, myParentComposite );
ContextInjectionFactory.make(TableToolbar.class, c2);

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