Paging & Sorting

Uses general find paging, reactive PageStream, aggregation pages, and ordered SortSpec appropriately.

General find paging

java

Flux<User> users = dsl
    .executeEntity(User.class, MongoTemplateName.FRONT)
    .fields(pair("status", "ACTIVE"))
    .end()
    .findAll()
    .paging(0, 20)
    .sorts(sort -> sort.desc("id"))
    .execute();

pageNumber is 0-based. A nested builder in the form of paging().pageNumber(...).pageSize(...).and() can also be used.

PageStream

java

PageStream<User> page = dsl
    .executeEntity(User.class, MongoTemplateName.FRONT)
    .fields(pair("status", "ACTIVE"))
    .end()
    .findAll()
    .paging(0, 20)
    .executePageStream();

Flux<User> data = page.data();
Mono<Long> totalCount = page.totalCount();

대량 처리에서 data를 즉시 List로 모으고 싶지 않다면 PageStream을 사용합니다. 필요하면 collectToPageResult()로 PageResult<T>로 변환할 수 있습니다.

Aggregation paging

java

PageStream<User> page = dsl
    .executeEntity(User.class, MongoTemplateName.FRONT)
    .fields(pair("status", "ACTIVE"))
    .end()
    .findAll()
    .paging(0, 20)
    .executeAggregationPageStream();

Mono<PageResult<User>> collected = dsl
    .executeEntity(User.class, MongoTemplateName.FRONT)
    .fields(pair("status", "ACTIVE"))
    .end()
    .findAll()
    .paging(0, 20)
    .executeAggregation();

executeAggregation()은 reactive page data를 최종 List로 collect해 PageResult<T>를 만듭니다. stream 상태가 중요하면 executeAggregationPageStream()을 사용합니다.

SortSpec

java

.sorts(sort -> sort
    .desc("score")
    .asc("createdAt")
    .desc("id")
    .driver(Sorts.metaTextScore("textScore"))
)

The sort key maintains the order in which it was added. Dynamic direction can use sort.of(direction, field) and Driver-native sort can be mixed with driver(Bson).

For stable pagination, use a unique secondary sort.

For lists with many identical score/date values, adding a stable and unique field like _id at the end can reduce page boundary issues.