Flink实战-定时器实现已完成订单自动五星好评

 public static class MySource implements SourceFunction<Tuple2<String,Long>>{
  private volatile boolean isRunning = true;

  @Override
  public void run(SourceContext<Tuple2<String,Long>> ctx) throws Exception{
   while (isRunning){
    Thread.sleep(1000);
    //订单id
    String orderid = UUID.randomUUID().toString();
    //订单完成时间
    long orderFinishTime = System.currentTimeMillis();
    ctx.collect(Tuple2.of(orderid, orderFinishTime));
   }
  }

  @Override
  public void cancel(){
   isRunning = false;
  }
 }

 public static class TimerProcessFuntion
   extends KeyedProcessFunction<Tuple,Tuple2<String,Long>,Object>{

  private MapState<String,Long> mapState;
  //超过多长时间(interval,单位：毫秒) 没有评价，则自动五星好评
  private long interval = 0l;

  public TimerProcessFuntion(long interval){
   this.interval = interval;
  }

  @Override
  public void open(Configuration parameters){
   MapStateDescriptor<String,Long> mapStateDesc = new MapStateDescriptor<>(
     "mapStateDesc",
     String.class, Long.class);
   mapState = getRuntimeContext().getMapState(mapStateDesc);
  }

  @Override
  public void onTimer(
    long timestamp, OnTimerContext ctx, Collector<Object> out) throws Exception{
   Iterator iterator = mapState.iterator();
   while (iterator.hasNext()){
    Map.Entry<String,Long> entry = (Map.Entry<String,Long>) iterator.next();

    String orderid = entry.getKey();
    boolean f = isEvaluation(entry.getKey());
    mapState.remove(orderid);
    if (f){
     LOG.info("订单(orderid: {}) 在  {} 毫秒时间内已经评价，不做处理", orderid, interval);
    }
    if (f){
     //如果用户没有做评价，在调用相关的接口给与默认的五星评价
     LOG.info("订单(orderid: {}) 超过  {} 毫秒未评价，调用接口给与五星自动好评", orderid, interval);
    }
   }
  }

  /**
   * 用户是否对该订单进行了评价，在生产环境下，可以去查询相关的订单系统.
   * 我们这里只是随便做了一个判断
   *
   * @param key
   * @return
   */
  private boolean isEvaluation(String key){
   return key.hashCode() % 2 == 0;
  }

  @Override
  public void processElement(
    Tuple2<String,Long> value, Context ctx, Collector<Object> out) throws Exception{
   mapState.put(value.f0, value.f1);
   ctx.timerService().registerProcessingTimeTimer(value.f1 + interval);
  }
 }