DI container, Inverse of Control

[nerobotParticipant]

Hi. I wrote IoC-container (inverse of control) that helps us incapsulate creation of new instances.

It named Di to be short, that mean dependancy inversion.

This container stores bindings of type T1,T2,.. with their realization.

You can bind interface type with its concrete realization.

The goal is to reduce creation of instances by New and use container instead.

Short example:

Monkey

' w/o ioc-container Local presenter:=New Presenter( New Game,New LocalMetrica,New OutputLogger ) ' with it Local presenter:=Di.Resolve<Presenter>()

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' w/o ioc-container Local presenter:=New Presenter( New Game,New LocalMetrica,New OutputLogger ) ' with it Local presenter:=Di.Resolve<Presenter>()

Yes, you must create all these Game, Metrica, Logger – but in special place, not in your business logic.

Important: Di store reference to functions, that will create our realization. If you don’t call, for example Di.Resolve then realization of ISomeModel will not be created at all.

It may be profit – if realization isn’t cost-free of resources etc.

But the main profit is – you can access needed instances in any place of your app w/o worrying about what params you should pass into constructor.

And if you need to change realization – you can change the only place where you setup container and it’ll change all of places where it used.

Ok, there is a code with 2 exaples.

Monkey

Namespace myapp #Import "<std>" Using std.. Function Main() SetupDi() ' Example #1 ' ' let's get data provider ' we know nothing about its realization ' all we need to know that it is IDataProvider with GetData() method Local provider:=Di.Resolve<IDataProvider>() ' we can do some work with data Local data:=provider.GetData() If data And data.Length>0 Local k:=1 Local min:=data[0],max:=data[0] For Local i:=Eachin data Print k+": "+i ' print each value min=Min( min,i ) max=Max( max,i ) k+=1 Next Print "min: "+min Print "max: "+max Endif ' Example #2 ' Local presenter:=Di.Resolve<Presenter>() ' we know nothing about Game, Logger, Metrica! presenter.ClickOnPlay() presenter.UseCheat( "monkey2-di-works") End #Rem monkeydoc Setup (bind) needed interfaces and it's realizations. #End Function SetupDi() ' Example #1 ' ' Di.Bind( Lambda:IDataProvider() ' Print "create production DataProvider" ' Return New DataProvider ' End ) Di.Bind( Lambda:IDataProvider() Print "create develop DataProvider" Return New TestDataProvider End ) ' Example #2 ' Di.Bind( Lambda:IMetrica() Return New LocalMetrica End ) Di.Bind( Lambda:ILogger() Return New OutputLogger End ) Di.Bind( Lambda:Game() Return New Game End ) Di.Bind( Lambda:Presenter() Return New Presenter( ' we pass instances that were already binded ' this call will occur when (if) we call Di.Resolve<Presenter>() Di.Resolve<Game>(), Di.Resolve<IMetrica>(), Di.Resolve<ILogger>() ) End ) End ' ---------------------------------------- ' Some code for demonstration #1 ' Interface IDataProvider Method GetData:Int[]() End Class DataProvider Implements IDataProvider Method GetData:Int[]() Local arr:=New Int[100] For Local i:=0 Until 100 arr[i]=Rnd( 0,1000 ) Next Return arr End End Class TestDataProvider Implements IDataProvider Method GetData:Int[]() Local arr:=New Int[20] For Local i:=0 Until 20 arr[i]=Rnd( -1000,0 ) Next Return arr End End ' ---------------------------------------- ' ---------------------------------------- ' Some code for demonstration #2 ' Interface ILogger Method Log( msg:String ) End Class OutputLogger Implements ILogger Method Log( msg:String ) Print "log: "+msg End End Interface IMetrica Method Add( msg:String,args:String="" ) End Class LocalMetrica Implements IMetrica Method Add( msg:String,args:String="" ) Local s:=LoadString( "asset::metrica.json" ) s += "~n"+msg+"~n"+args+"~n----------------------" SaveString( s,"asset::metrica.json" ) End End Class Game Method Play() Print "game. play" End Method Stop() Print "game. stop" End End Class Presenter Method New( game:Game,metrica:IMetrica,logger:ILogger ) _game=game _metrica=metrica _logger=logger End Method ClickOnPlay() _game.Play() _metrica.Add( "ClickOnPlay" ) End Method ClickOnStop() _game.Stop() _metrica.Add( "ClickOnStop" ) End Method UseCheat( cheatCode:String ) _logger.Log( "useCheat: "+cheatCode ) End Private Field _game:Game Field _metrica:IMetrica Field _logger:ILogger End ' ---------------------------------------- #Rem monkeydoc Container class that stores bindings of type <-> realization_of_type. Type can be interface or class type. #End Class Di Final #Rem monkeydoc This function add new binding. You can add the only type of T function. @param bindFunc a function that provide realization of T type @param singleton if true - we want to have the only instance of T (singleton), if false - we want to instantiate new T every call of Resolve() #End Function Bind<T>( bindFunc:T(),singleton:Bool=True ) Local type:=Typeof<T> If singleton Assert( Not BINDERS_SINGLE.Contains( type ),"Di-container : type "+type+" already exists!" ) BINDERS_SINGLE[type]=bindFunc Else Assert( Not BINDERS_NEW_INST.Contains( type ),"Di-container : type "+type+" already exists!" ) BINDERS_NEW_INST[type]=bindFunc Endif End #Rem monkeydoc This function return instance of T. If type was added as singleton - we always will get the same instance. Otherwise - we always will get new instance. #End Function Resolve<T>:T() Local type:=Typeof<T> Local binder:=BINDERS_NEW_INST[type] If binder<>Null Return Cast<T()>( binder )() Endif Local result:=SINGLETONS[type] If result=Null binder=BINDERS_SINGLE[type] If binder Local result2:=Cast<T()>( binder )() Assert( result2<>Null,"Di-container: realization for "+type+" not found!" ) SINGLETONS[type]=result2 Return result2 Endif Endif Assert( result<>Null,"Di-container: realization for "+type+" not found!" ) Return Cast<T>( result ) End Private Const SINGLETONS:=New Map<TypeInfo,Variant> Const BINDERS_NEW_INST:=New Map<TypeInfo,Variant> Const BINDERS_SINGLE:=New Map<TypeInfo,Variant> End

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Namespace myapp   #Import "<std>"   Using std..   Function Main() SetupDi() ' Example #1 ' ' let's get data provider ' we know nothing about its realization ' all we need to know that it is IDataProvider with GetData() method Local provider:=Di.Resolve<IDataProvider>() ' we can do some work with data Local data:=provider.GetData() If data And data.Length>0 Local k:=1 Local min:=data[0],max:=data[0] For Local i:=Eachin data Print k+": "+i ' print each value min=Min( min,i ) max=Max( max,i ) k+=1 Next Print "min: "+min Print "max: "+max Endif ' Example #2 ' Local presenter:=Di.Resolve<Presenter>() ' we know nothing about Game, Logger, Metrica! presenter.ClickOnPlay() presenter.UseCheat( "monkey2-di-works") End   #Rem monkeydoc Setup (bind) needed interfaces and it's realizations. #End Function SetupDi() ' Example #1 ' ' Di.Bind( Lambda:IDataProvider() ' Print "create production DataProvider" ' Return New DataProvider ' End ) Di.Bind( Lambda:IDataProvider() Print "create develop DataProvider" Return New TestDataProvider End ) ' Example #2 ' Di.Bind( Lambda:IMetrica() Return New LocalMetrica End ) Di.Bind( Lambda:ILogger() Return New OutputLogger End ) Di.Bind( Lambda:Game() Return New Game End ) Di.Bind( Lambda:Presenter() Return New Presenter( ' we pass instances that were already binded ' this call will occur when (if) we call Di.Resolve<Presenter>() Di.Resolve<Game>(), Di.Resolve<IMetrica>(), Di.Resolve<ILogger>() ) End ) End     ' ---------------------------------------- ' Some code for demonstration #1 ' Interface IDataProvider Method GetData:Int[]() End   Class DataProvider Implements IDataProvider Method GetData:Int[]() Local arr:=New Int[100] For Local i:=0 Until 100 arr[i]=Rnd( 0,1000 ) Next Return arr End End   Class TestDataProvider Implements IDataProvider Method GetData:Int[]() Local arr:=New Int[20] For Local i:=0 Until 20 arr[i]=Rnd( -1000,0 ) Next Return arr End End ' ----------------------------------------   ' ---------------------------------------- ' Some code for demonstration #2 ' Interface ILogger Method Log( msg:String ) End   Class OutputLogger Implements ILogger Method Log( msg:String ) Print "log: "+msg End End   Interface IMetrica Method Add( msg:String,args:String="" ) End   Class LocalMetrica Implements IMetrica Method Add( msg:String,args:String="" ) Local s:=LoadString( "asset::metrica.json" ) s += "~n"+msg+"~n"+args+"~n----------------------" SaveString( s,"asset::metrica.json" ) End End   Class Game Method Play() Print "game. play" End Method Stop() Print "game. stop" End End     Class Presenter Method New( game:Game,metrica:IMetrica,logger:ILogger ) _game=game _metrica=metrica _logger=logger End Method ClickOnPlay() _game.Play() _metrica.Add( "ClickOnPlay" ) End Method ClickOnStop() _game.Stop() _metrica.Add( "ClickOnStop" ) End Method UseCheat( cheatCode:String ) _logger.Log( "useCheat: "+cheatCode ) End Private Field _game:Game Field _metrica:IMetrica Field _logger:ILogger End   ' ----------------------------------------     #Rem monkeydoc Container class that stores bindings of type <-> realization_of_type. Type can be interface or class type. #End Class Di Final #Rem monkeydoc This function add new binding. You can add the only type of T function. @param bindFunc a function that provide realization of T type @param singleton if true - we want to have the only instance of T (singleton), if false - we want to instantiate new T every call of Resolve() #End Function Bind<T>( bindFunc:T(),singleton:Bool=True ) Local type:=Typeof<T> If singleton Assert( Not BINDERS_SINGLE.Contains( type ),"Di-container : type "+type+" already exists!" ) BINDERS_SINGLE[type]=bindFunc Else Assert( Not BINDERS_NEW_INST.Contains( type ),"Di-container : type "+type+" already exists!" ) BINDERS_NEW_INST[type]=bindFunc Endif   End #Rem monkeydoc This function return instance of T. If type was added as singleton - we always will get the same instance. Otherwise - we always will get new instance. #End Function Resolve<T>:T() Local type:=Typeof<T> Local binder:=BINDERS_NEW_INST[type] If binder<>Null Return Cast<T()>( binder )() Endif Local result:=SINGLETONS[type] If result=Null binder=BINDERS_SINGLE[type] If binder Local result2:=Cast<T()>( binder )() Assert( result2<>Null,"Di-container: realization for "+type+" not found!" ) SINGLETONS[type]=result2 Return result2 Endif Endif Assert( result<>Null,"Di-container: realization for "+type+" not found!" ) Return Cast<T>( result ) End Private Const SINGLETONS:=New Map<TypeInfo,Variant> Const BINDERS_NEW_INST:=New Map<TypeInfo,Variant> Const BINDERS_SINGLE:=New Map<TypeInfo,Variant> End

And separated Di class:

Monkey

#Rem monkeydoc Container class that stores bindings of type <-> realization_of_type. Type can be interface or class type. #End Class Di Final #Rem monkeydoc This function add new binding. You can add the only type of T function. @param bindFunc a function that provide realization of T type @param singleton if true - we want to have the only instance of T (singleton), if false - we want to instantiate new T every call of Resolve() #End Function Bind<T>( bindFunc:T(),singleton:Bool=True ) Local type:=Typeof<T> If singleton Assert( Not BINDERS_SINGLE.Contains( type ),"Di-container : type "+type+" already exists!" ) BINDERS_SINGLE[type]=bindFunc Else Assert( Not BINDERS_NEW_INST.Contains( type ),"Di-container : type "+type+" already exists!" ) BINDERS_NEW_INST[type]=bindFunc Endif End #Rem monkeydoc This function return instance of T. If type was added as singleton - we always will get the same instance. Otherwise - we always will get new instance. #End Function Resolve<T>:T() Local type:=Typeof<T> Local binder:=BINDERS_NEW_INST[type] If binder<>Null Return Cast<T()>( binder )() Endif Local result:=SINGLETONS[type] If result=Null binder=BINDERS_SINGLE[type] If binder Local result2:=Cast<T()>( binder )() Assert( result2<>Null,"Di-container: realization for "+type+" not found!" ) SINGLETONS[type]=result2 Return result2 Endif Endif Assert( result<>Null,"Di-container: realization for "+type+" not found!" ) Return Cast<T>( result ) End Private Const SINGLETONS:=New Map<TypeInfo,Variant> Const BINDERS_NEW_INST:=New Map<TypeInfo,Variant> Const BINDERS_SINGLE:=New Map<TypeInfo,Variant> End

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#Rem monkeydoc Container class that stores bindings of type <-> realization_of_type. Type can be interface or class type. #End Class Di Final #Rem monkeydoc This function add new binding. You can add the only type of T function. @param bindFunc a function that provide realization of T type @param singleton if true - we want to have the only instance of T (singleton), if false - we want to instantiate new T every call of Resolve() #End Function Bind<T>( bindFunc:T(),singleton:Bool=True ) Local type:=Typeof<T> If singleton Assert( Not BINDERS_SINGLE.Contains( type ),"Di-container : type "+type+" already exists!" ) BINDERS_SINGLE[type]=bindFunc Else Assert( Not BINDERS_NEW_INST.Contains( type ),"Di-container : type "+type+" already exists!" ) BINDERS_NEW_INST[type]=bindFunc Endif   End #Rem monkeydoc This function return instance of T. If type was added as singleton - we always will get the same instance. Otherwise - we always will get new instance. #End Function Resolve<T>:T() Local type:=Typeof<T> Local binder:=BINDERS_NEW_INST[type] If binder<>Null Return Cast<T()>( binder )() Endif Local result:=SINGLETONS[type] If result=Null binder=BINDERS_SINGLE[type] If binder Local result2:=Cast<T()>( binder )() Assert( result2<>Null,"Di-container: realization for "+type+" not found!" ) SINGLETONS[type]=result2 Return result2 Endif Endif Assert( result<>Null,"Di-container: realization for "+type+" not found!" ) Return Cast<T>( result ) End Private Const SINGLETONS:=New Map<TypeInfo,Variant> Const BINDERS_NEW_INST:=New Map<TypeInfo,Variant> Const BINDERS_SINGLE:=New Map<TypeInfo,Variant> End

[nerobotParticipant]

I created repository for that:

https://github.com/engor/m2-di-container

Repository contains core class di.monkey2  and two demo programs.

Also I changed code above – FuncWrapper was removed.

PS: such containers are suitable for apps, and much less for games.

[mac767Participant]

Hi nerobot,

very useful for clean code in large projects.
Thanks for sharing.

[Author]

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