Implementing multiple interfaces with Java - is there a way to delegate

Question

I need to create a base class that implements several interfaces with lots of methods  example below   Is there an easier way to delegate these method calls without having to create a horde of duplicate methods   public class MultipleInterfaces implements InterFaceOne  InterFaceTwo        private InterFaceOne if1      private InterFaceTwo if2       public MultipleInterfaces           if1   new ImplementingClassOne          if2   new ImplementingClassTwo                Override     public void classOneMethodOne   if1 methodOne           Override     public void classOneMethodTwo   if1 methodTwo              Etc            Override     public void classTwoMethodOne   if2 methodOne           Override     public void classTwoMethodTwo   if2 methodTwo              Etc

User · Answer

Unfortunately  NO   We re all eagerly awaiting the Java support for extension methods

User · Answer

There is one way to implement multiple interface   Just extend one interface from another or create interface that extends predefined interface Ex   public interface PlnRow CallBack extends OnDateSetListener       public void Plan Removed        public BaseDB getDB        now we have interface that extends another interface to use in out class just use this new interface who implements two or more interfaces  public class Calculator extends FragmentActivity implements PlnRow CallBack         Override     public void onDateSet DatePicker view  int year  int monthOfYear  int dayOfMonth                 Override     public void Plan Removed                  Override     public BaseDB getDB                hope this helps

User · Answer

There s no pretty way  You might be able to use a proxy with the handler having the target methods and delegating everything else to them  Of course you ll have to use a factory because there ll be no constructor

User · Answer

As said  there s no way  However  a bit decent IDE can autogenerate delegate methods  For example Eclipse can do  First setup a template   public class MultipleInterfaces implements InterFaceOne  InterFaceTwo       private InterFaceOne if1      private InterFaceTwo if2      then rightclick  choose Source   Generate Delegate Methods and tick the both if1 and if2 fields and click OK   See also the following screens

[java] Implementing multiple interfaces with Java - is there a way to delegate?

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