多个inputstream的情况下，watermark的值怎么赋值？ kakfa中多个partition提取 watermark

1,
org.apache.flink.streaming.api.operators; AbstractStreamOperator

public void processWatermark1(Watermark mark) throws Exception {
   input1Watermark = mark.getTimestamp();
   long newMin = Math.min(input1Watermark, input2Watermark);
   if (newMin > combinedWatermark) {
      combinedWatermark = newMin;
      processWatermark(new Watermark(combinedWatermark));
   }
}

public void processWatermark2(Watermark mark) throws Exception {
   input2Watermark = mark.getTimestamp();
   long newMin = Math.min(input1Watermark, input2Watermark);
   if (newMin > combinedWatermark) {
      combinedWatermark = newMin;
      processWatermark(new Watermark(combinedWatermark));
   }
}

2,
http://vinoyang.com/2016/10/29/flink-streaming-window-operator-analysis/

3, kakfa中多个partition提取 watermark

private static class PeriodicWatermarkEmitter<KPH> implements ProcessingTimeCallback 

public void onProcessingTime(long timestamp) throws Exception {

   long minAcrossAll = Long.MAX_VALUE;
   boolean isEffectiveMinAggregation = false;
   for (KafkaTopicPartitionState<?> state : allPartitions) {

      // we access the current watermark for the periodic assigners under the state
      // lock, to prevent concurrent modification to any internal variables
      final long curr;
      //noinspection SynchronizationOnLocalVariableOrMethodParameter
      synchronized (state) {
         curr = ((KafkaTopicPartitionStateWithPeriodicWatermarks<?, ?>) state).getCurrentWatermarkTimestamp();
      }

      minAcrossAll = Math.min(minAcrossAll, curr);
      isEffectiveMinAggregation = true;
   }

   // emit next watermark, if there is one
   if (isEffectiveMinAggregation && minAcrossAll > lastWatermarkTimestamp) {
      lastWatermarkTimestamp = minAcrossAll;
      emitter.emitWatermark(new Watermark(minAcrossAll));
   }

   // schedule the next watermark
   timerService.registerTimer(timerService.getCurrentProcessingTime() + interval, this);
}