JavaDude Tools->Annotations->Annotations examples

Mixin Example

Note: I'm not a fan of the "I" prefix on interfaces, but I'm using it here to make it more clear which types are interfaces vs classes.

Suppose we have the following three interfaces:

``` package sample;

import java.util.List;

public interface IFlightAgent { List getFlight(); void reserve(IFlight flight); }

public interface ICarAgent { List getCars(); void reserve(ICar car); }

public interface IHotelAgent { List getHotels(); void reserve(IHotel hotel); } ```

each with a corresponding implementation (FlightAgentImpl, CarAgentImpl, HotelAgentImpl), and we'd like to create a single aggregate TravelAgent that "mixes in" all of the function of these three.

You can specify the following:

``` package sample;

import com.javadude.annotation.Bean; import com.javadude.annotation.Delegate;

@Bean(delegates = { @Delegate(type = IHotelAgent.class, property = "hotelAgent", instantiateAs = HotelAgentImpl.class), @Delegate(type = ICarAgent.class, property = "carAgent", instantiateAs = CarAgentImpl.class), @Delegate(type = IFlightAgent.class, property = "flightAgent", instantiateAs = FlightAgentImpl.class) } ) public class TravelAgent extends TravelAgentGen implements IHotelAgent, ICarAgent, IFlightAgent {

} ```

This will generate TravelAgentGen that creates instances of the "impl" classes and delegation methods for each of the specified interfaces:

``` // CODE GENERATED BY JAVADUDE BEAN ANNOTATION PROCESSOR // -- DO NOT EDIT - THIS CODE WILL BE REGENERATED! -- package sample;

@javax.annotation.Generated( value = "com.javadude.annotation.processors.BeanAnnotationProcessor", date = "Thu Aug 14 23:25:48 EDT 2008", comments = "CODE GENERATED BY JAVADUDE BEAN ANNOTATION PROCESSOR; DO NOT EDIT! THIS CODE WILL BE REGENERATED!") public abstract class TravelAgentGen { private sample.IHotelAgent hotelAgent_; private sample.ICarAgent carAgent_; private sample.IFlightAgent flightAgent_; public TravelAgentGen() { ; hotelAgent_ = new sample.HotelAgentImpl(); carAgent_ = new sample.CarAgentImpl(); flightAgent_ = new sample.FlightAgentImpl(); }

public java.util.List<sample.IHotel> getHotels() {
    return hotelAgent_.getHotels();
}
public void reserve(sample.IHotel hotel) {
    hotelAgent_.reserve(hotel);
}
public java.util.List<sample.ICar> getCars() {
    return carAgent_.getCars();
}
public void reserve(sample.ICar car) {
    carAgent_.reserve(car);
}
public java.util.List<sample.IFlight> getFlight() {
    return flightAgent_.getFlight();
}
public void reserve(sample.IFlight flight) {
    flightAgent_.reserve(flight);
}
@Override
public java.lang.String toString() {
    return getClass().getName() + '[' + paramString() + ']';
}
protected java.lang.String paramString() {
    return "";
}

} ```

JavaDude Tools->Annotations->Annotations examples