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. */
}
This question is related to
java
interface
delegation
The answer is
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:
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.
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
Unfortunately: NO.
We're all eagerly awaiting the Java support for extension methods
Source: Stackoverflow.com