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Injector is missing a rule to handle injection into target

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jeremy.brooks

26 Apr, 2012 03:43 PM

Hi, I am building a modular application using robotlegs 1.5 and the utilities-modular library.

I've come up against a weird issue where I think I've set up a rule for an injection, but this fails at runtime.

Here is some code snippets showing the rule and injection, hopefully I've missed something obvious?

Context:

override public function startup():void{
        //map view class type, required for correct injection of modules.
        viewMap.mapType(IModule);

        //mediatorMap
        mediatorMap.mapView(MapAPIModuleShell, MapAPIModuleShellMediator);

        //model
        injector.mapSingleton(BoundingBox);

        //commandMap
        moduleCommandMap.mapEvent(BoundingBoxEvent.BOUNDING_BOX_IN_LAT_LONG, SaveBoundingBoxCommand);

Command and injection:

    [Inject]
    public var bbox:BoundingBox;

    [Inject]
    public var event:BoundingBoxEvent;

    /**
     * Handles saving bounding box to model object.
     * TODO: handle metres.
     * */
    override public function execute():void{
        if (event.type == BoundingBoxEvent.BOUNDING_BOX_IN_LAT_LONG){
            bbox = event.boundingBox;
        } else if (event.type == BoundingBoxEvent.BOUNDING_BOX_IN_METRES){
            bbox = event.boundingBox;
        }
        //TODO: dispatch that the bounding box state has been saved
    }

Here is the top of the stack trace:

 Error: Injector is missing a rule to handle injection into target [class BoundingBox]. Target dependency: Number, method: constructor, parameter: 1
at org.swiftsuspenders.injectionpoints::MethodInjectionPoint/gatherParameterValues()[/Development/Projects/SwiftSuspenders/src/org/swiftsuspenders/injectionpoints/MethodInjectionPoint.as:110]
at org.swiftsuspenders.injectionpoints::ConstructorInjectionPoint/applyInjection()[/Development/Projects/SwiftSuspenders/src/org/swiftsuspenders/injectionpoints/ConstructorInjectionPoint.as:37]
at org.swiftsuspenders::Injector/instantiate()[/Development/Projects/SwiftSuspenders/src/org/swiftsuspenders/Injector.as:138]

Any ideas?

1. Support Staff 2 Posted by Shaun Smith on 26 Apr, 2012 03:55 PM

   

   Hello,

   What does constructor of BoundingBox look like? The injector is saying that it doesn't know how to provide the first constructor argument of BoundingBox (which is a Number) when it tries to construct it.

   Also, your command has a dependency on BoundingBox, yet it also maps BoundingBox as a singleton when it executes. Have you mapped the BoundingBox elsewhere, and are you intending to overwrite the mapping in the command?

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2. 3 Posted by jeremy.brooks on 26 Apr, 2012 03:58 PM

   

   Just spotted that I left in the extra injection in the command, didn't mean to leave that in, I was experimenting, I've edited it now, thanks for the spot Shaun.

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3. 4 Posted by jeremy.brooks on 26 Apr, 2012 03:59 PM

   

   The bounding box constructor looks like this;

     public function BoundingBox(minx:Number, miny:Number, maxx:Number, maxy:Number, srs:String = "EPSG:4326"){
       _minx = minx;
       _miny = miny;
       _maxx = maxx;
       _maxy = maxy;
       _srs = srs;
   }
   

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4. 5 Posted by jeremy.brooks on 26 Apr, 2012 04:06 PM

   

   Shaun, you sparked an idea there, so instead of using mapsingleton I've used mapValue, providing a default object, worked great, thanks!

   injector.mapValue(BoundingBox, new BoundingBox(0,0,0,0));

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5. Support Staff 6 Posted by Shaun Smith on 26 Apr, 2012 04:09 PM

   

   Aha, that's the problem right there :)

   The injector has no idea how to create an instance of BoundingBox - it doesn't know how to provide any of the constructor arguments. You have a couple of options:

   1. Make all the ctor arguments optional (with default values)
   2. Provide the instance yourself when doing the mapping: injector.mapValue(BoundingBox, new BoundingBox(7,5,90,90));

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6. Support Staff 7 Posted by Shaun Smith on 26 Apr, 2012 04:09 PM

   

   You beat me to it :)

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7. Shaun Smith closed this discussion on 26 Apr, 2012 04:09 PM.

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