HandlerChain 执行逻辑是什么？

[besodata]

@EventRule("/Event-Output/TagA-Output/**")
@component("emailHandler")
public class EmailDisruptorHandler implements DisruptorHandler {

@Override
public void doHandler(DisruptorBindEvent event, HandlerChain<DisruptorBindEvent> handlerChain) throws Exception {
	System.out.println(event.toString());
}

}
其中handlerChain怎么执行event？