DelegatingApplicationListener.java 文件源码

@Override
public void onApplicationEvent(ApplicationEvent event) {
    if (event instanceof ApplicationEnvironmentPreparedEvent) {
        List<ApplicationListener<ApplicationEvent>> delegates = getListeners(
                ((ApplicationEnvironmentPreparedEvent) event).getEnvironment());
        if (delegates.isEmpty()) {
            return;
        }
        this.multicaster = new SimpleApplicationEventMulticaster();
        for (ApplicationListener<ApplicationEvent> listener : delegates) {
            this.multicaster.addApplicationListener(listener);
        }
    }
    if (this.multicaster != null) {
        this.multicaster.multicastEvent(event);
    }
}