[Solved] You want to compute the total sales amount per product category from a Kafka stream sales where each record has category and... Which Kafka Streams code snippet correctly performs this aggregation? | Kafka

Kafka - Streams

You want to compute the total sales amount per product category from a Kafka stream sales where each record has category and amount. Which Kafka Streams code snippet correctly performs this aggregation?

Asales.groupBy((key, sale) -> sale.category).aggregate(() -> 0.0, (key, newVal, agg) -> agg + newVal.amount);

Bsales.groupBy((key, sale) -> sale.category).reduce((agg, newVal) -> agg + newVal.amount);

Csales.groupByKey().count();

Dsales.countBy((key, sale) -> sale.category);

Step-by-Step Solution

Solution:

Step 1: Choose aggregation method for summing amounts
To sum amounts, use aggregate() with initializer and adder function.
Step 2: Verify groupBy key selector and aggregation logic
Grouping by sale.category and adding newVal.amount to accumulator is correct.
Final Answer:
sales.groupBy((key, sale) -> sale.category).aggregate(() -> 0.0, (key, newVal, agg) -> agg + newVal.amount); -> Option A
Quick Check:
aggregate with initializer sums amounts per category [OK]

Quick Trick: Use aggregate() with initializer to sum values per group [OK]

Common Mistakes:

MISTAKES

Using reduce() without matching types
Calling count() instead of sum
Using non-existent countBy() method

Master "Streams" in Kafka

9 interactive learning modes - each teaches the same concept differently

Learn Why Deep Visual Try Challenge Project Recall Time

More Kafka Quizzes

Which Kafka Streams code snippet correctly performs this aggregation?

Step 1: Choose aggregation method for summing amounts

Step 2: Verify groupBy key selector and aggregation logic

Final Answer:

Quick Check:

Want More Practice?