Aggregate over a column: the proper way to do

[sam smith]

I want to aggregate a column by counting the number of rows having the
value "myTargetValue" and return the result
I am doing it like the following:in JAVA

> long result =
> dataset.filter(dataset.col("myCol").equalTo("myTargetVal")).groupBy(col("myCol")).agg(count(dataset.col("myCol"))).select("count(myCol)").first().getLong(0);


Is that the right way? if no, what if a more optimized way to do that
(always in JAVA)?
Thanks for the help.