public List<String> getAgentIdList() {
        List<String> list = new ArrayList<>();
        for (ServerGroup serverGroup : this.serverGroupList) {
            List<ServerInstance> instanceList = serverGroup.getInstanceList();
            for (ServerInstance serverInstance : instanceList) {
                String name = serverInstance.getName();
                list.add(name);
            }
        }
        return list;
    }
@author emeroad
@author netspider
@author minwoo.jung
@author HyunGil Jeong
web/src/main/java/com/navercorp/pinpoint/web/applicationmap/nodes/ServerGroupList.java