code: public SingleOutputStreamOperator<T> min(String field) {
  		return aggregate(new ComparableAggregator<>(field, input.getType(), AggregationFunction.AggregationType.MIN, false, input.getExecutionConfig()));
  	}
docs: Applies an aggregation that that gives the minimum value of the pojo data
  stream at the given field expression for every window.
  
  <p>A field expression is either the name of a public field or a getter method with
  parentheses of the {@link DataStream}S underlying type. A dot can be used to drill down into
  objects, as in {@code "field1.getInnerField2()" }.
  
  @param field The field expression based on which the aggregation will be applied.
  @return The transformed DataStream.