Aggregation Java

Question 1

Which factory class should be used for building aggregation pipeline stages?

Answer 1

The Aggregates class

Question 2

Which factory class can be used to sort data?

Answer 2

The Sorts class

Question 3

Which factory class can be used to project data?

Answer 3

The Projections class

Question 4

Code an example of the aggregation pipeline strucutre

Answer 4

collection.aggregate(List.of(Aggregates1, Aggregates2, ...))

Question 5

Code an example using the match stage with multiple field criteria

Answer 5

var matchStage = match(and(eq(field, value), eq(field2, value2)));
collection.aggregate(List.of(matchStage));

Question 6

Code an example using the group stage

Answer 6

var groupStage = group("$groupKey", Accumulators...));
collection.aggregate(List.of(groupStage));

Question 7

Which class should you use to perform accumulator operations?

Answer 7

The Accumulators class

Question 8

Code an example using an ascending sort and limit stage

Answer 8

var sortStage = sort(Sorts.ascending(field1, field2));
var limitStage = limit(number);
collection.aggregate(List.of(sortStage, limitStage));

Question 9

Code an example of using the project stage

Answer 9

var projectStage = project(Projections...);
document.aggregate(List.of(projectStage));

Question 10

Code an example using the out stage

Answer 10

var outStage = out("collectionName");
collection.aggregate(List.of(outStage));