contract EventSubscriber {
  function onCreate() {
    Global.message = '';
    Global.events = [];
  }
  export function init(topic) {
    print(topic);
    YancloudUtil.subscribe(topic, handler);
    return 'done';
  }
  function handler(e) {
    var ret = 'receive event, topic: ' + e.topic + ' semantics: ' + e.semantics +
      ' content:\n' + JSON.stringify(e.content);
    Global.message = ret;
    Global.events.push(e.getAll());
  }
  export function getMsg() {
    return Global.message;
  }
  export function getEves() {
    return JSON.stringify(Global.events);
  }
}