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From: "Leif Roar Moldskred" <leif.roar.moldskred@1:261/38.remove-nlb-this>
Subject: Re: multiple inheritance
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Date: Mon, 13 Aug 2012 18:36:21 GMT
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  To: Arne Vajhøj
From: Leif Roar Moldskred <leifm@dimnakorr.com>

Arne Vajh-,j <arne@vajhoej.dk> wrote:
> On 8/2/2012 4:10 AM, Roedy Green wrote:
>>
>> 1. It has interfaces which gives much of the ability at lighter
>> weight..
>
> Only for a very limited type of types (those with no implementation
> at all).

At times, I've wished that Java had automatic delegation (composition) in 
addition to inheritance and interface implementation, where the compiler 
automatically adds the public methods and fields from delegated objects, except 
when there's a conflict of names. Something like this, maybe:


public class ClassAlfa {
  public void alfaMethod( ) { ... }
  public void sharedMethod( ) { ... }
  public void anotherSharedMethod( ) { ... }
}

public class ClassBeta {
  public void betaMethod( ) { ... }
  public void sharedMethod( ) { ... }
  public void anotherSharedMethod( ) { ... }
}


public class Delegator {
  private delegate ClassAlfa ALFA;
  private delegate ClassBeta BETA;

  public void sharedMethod( ) {
    ALFA.sharedMethod( );
  }

  public void anotherSharedMethod( ) {
    ALFA.sharedMethod( );
    BETA.sharedMethod( );
  }
}

public class Example {
  public static void main( String[] args ) {
    private Delegator delegator;

    delegator.alfaMethod( );
    delegator.betaMethod( );
    delegator.sharedMethod( );
    delegator.anotherSharedMethod( );
  }
}

--
Leif Roar Moldskred

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