配置时间特性

def main(args: Array[String]) {

    // set up the streaming execution environment
    val env = StreamExecutionEnvironment.getExecutionEnvironment

    // use event time for the application
    env.setStreamTimeCharacteristic(TimeCharacteristic.EventTime)

//
// Source code recreated from a .class file by IntelliJ IDEA
// (powered by Fernflower decompiler)
//

package org.apache.flink.streaming.api;

import org.apache.flink.annotation.PublicEvolving;

@PublicEvolving
public enum TimeCharacteristic {
    ProcessingTime,
    IngestionTime,
    EventTime;

    private TimeCharacteristic() {
    }
}


  @PublicEvolving
    public void setStreamTimeCharacteristic(TimeCharacteristic characteristic) {
    //校验是否为空
        this.timeCharacteristic = (TimeCharacteristic)Preconditions.checkNotNull(characteristic);
        if (characteristic == TimeCharacteristic.ProcessingTime) {
            this.getConfig().setAutoWatermarkInterval(0L);
        } else {
            this.getConfig().setAutoWatermarkInterval(200L);
        }

    }

@Internal
public final class Preconditions {
    public static <T> T checkNotNull(T reference) {
        if (reference == null) {
            throw new NullPointerException();
        } else {
            return reference;
        }
    }