import { Injectable } from '@angular/core';

declare let $:any;
@Injectable()
export class CometdService {

  cometd_instance;
  cometd_listener;
  cometd_subcription;


  callback:any;
  constructor() {
  }

  setStatusChangedCallback(callback){
    this.callback = callback;
  }

  public run_cometd(self){
    if(this.callback==undefined){
      return;
    }
    this.cometd_instance = new $.Cometd();
    //第一步
    //配置需要监听的cometd服务器地址,具体决定于你需要监听的cometd消息。
    let cometdURL = location.protocol + "//" + location.host +"/cometd/cometd.msg";
    this.cometd_instance.configure({
          url: cometdURL,
          logLevel: 'info',
          connectTimeout: 3000
        });
    //第二步
    //添加握手后回调方法,握手成功的话,添加事件订阅处理
    this.cometd_listener = this.cometd_instance.addListener('/meta/handshake', (message: any) => {
          if (message.successful) {
              console.log('cometd,topo addListener successful');
              this.cometd_instance.batch(() => {
               this.subscribeStatusChanged(this.callback,self);
          });
        }
      });
    //握手
     this.cometd_instance.handshake();
  }

  //第三步
  //订阅关心的事件,此处是/statusChange/xxx,具体决定于服务器端发送的值。
  private subscribeStatusChanged(callback,self) {
      this.cometd_subcription = this.cometd_instance.subscribe('/statusChange/xxx', (message: any) => {
        console.log('get message: ', JSON.stringify(message));
        callback.call(self, message);
      });
  }


  // private close(){
    public close(){
    if (this.cometd_subcription) {
      this.cometd_instance.unsubscribe(this.cometd_subcription);
      this.cometd_subcription = null;
    }
    if (this.cometd_listener) {
      this.cometd_instance.removeListener(this.cometd_listener);
      this.cometd_listener = null;
    }
    if (this.cometd_instance) {
      //this.cometd_instance.reload();
      this.cometd_instance.getTransport().abort();
      this.cometd_instance.disconnect();
    }
  }

}
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