code: package de.tu_berlin.cit.watergridsense_pipelines.utils;
  
  import java.util.Date;
  
  import org.apache.flink.api.java.tuple.Tuple2;
  
  /**
   * Parameter cache contains the current and previous value of a given parameter
   */
  public class ParamCache {
  
      public Tuple2<Date, String> current;
      public Tuple2<Date, String> previous;
  
      public String toString() {
          String returnString = "";
          if (this.current != null) {
              returnString = returnString +
              "\nCurrent: " +
              new Date(this.current.f0.getTime()) +
              ", " +
              this.current.f1;
          }
          else {
              returnString = returnString +
              "Current: null";
          }
          if (this.previous != null) {
              returnString = returnString + 
              "\nPrevious: " +
              new Date(this.previous.f0.getTime()) +
              ", " +
              this.previous.f1;
          }
          else {
              returnString = returnString + 
                  "\nPrevious: null";
          }
          return returnString;
      }
  }