How to send List of Expression to Aggregate Function in Spark JAVA API

Question

I'm trying to execute below code using Spark JAVA api.

sampleDS=sampleDS
    .select(col("column1"),col("column2"),col("price1")col("price2"))
    .groupBy(col("column1"),col("column2"))
    .agg(expr("sum(price1)").as("MainPrice"),expr("sum(price2)").as("ExtPrice"))
    .sort(col("column1"),col("column2"));

But this part in the code I want that to be Dynamic,

.agg(expr("sum(price1)").as("MainPrice"),expr("sum(price2)").as("ExtPrice"))

which means only if a request has ExtPrice I need ExtPrice to be there , viceversa for MainPrice i.e. if only MainPrice is selected the code should be .agg(expr("sum(price1)")) or when only ExtPrice is selected .agg(expr("sum(price2)")) I tried adding the expressions in a List. Something but I got stuck there. Can anyone help me here sort this out?