Scala类实现两个Java接口 - 如何实现？

Question

I have just started learning Scala and I'm now wondering how I could implement two different Java interfaces with one Scala class? Let's say I have the following interfaces written in Java

public interface EventRecorder {
    public void abstract record(Event event); 
}

public interface TransactionCapable {
    public void abstract commit();
}

But a Scala class can extend only one class at a time. How can I have a Scala class that could fulfill both contracts? Do I have to map those interfaces into traits?

Note, my Scala classes would be used from Java as I am trying to inject new functionality written in Scala into an existing Java application. And the existing framework expects that both interface contracts are fulfilled.

Answer 1

The second interface can be implemented with the with keyword

class ImplementingClass extends EventRecorder with TransactionCapable {
  def record(event: Event) {}
  def commit() {}
}

Further on each subsequent interface is separated with the keyword with .

class Clazz extends InterfaceA
  with InterfaceB
  with InterfaceC {
  //...
}