Paginated results
The Query
API includes methods for returning paginated results. A paginated result prevents all query results from being returned at one time, potentially exceeding system memory. It allows you to incrementally return and process query results in batches.
In the following snippet, a object is returned that is limited to the first 10 User
objects.
PaginatedResult<User> results = Query.from(User.class)
.select(0, 10);
List<User> users = results.getItems();
-
Returns a
PaginatedResult
with . This method specifies the number of objects to return starting at a particular offset. If the offset were set to 5 and the limit set to 15, the method would return 15 instances starting at offset 5.
ThePaginatedResult
object only contains the number of objects specified inselect(long offset, int limit)
, which is typically a subset of the total objects retrieved. For example, a query might return a total of 1,000 objects, which can be determined with thegetCount
method onPaginatedResult
. -
Returns the objects contained by
PaginatedResult
.
To iterate query results in batches, use the PaginatedResult
methods hasNext()
and getNextOffset()
. The following snippet builds paginated results in batches of 100 objects.
int limit = 100;
Query<User> query = Query.from(User.class);
PaginatedResult<User> result = query.select(0, limit);
while (result.hasNext()) {
/* Do something with the current batch of items referenced in the result object */
result = query.select(result.getNextOffset(), limit);
}
-
Variable for limiting the number of retrieved records in a page.
-
Instantiates a
Query
object for searching users. -
Returns a
PaginatedResult
with the first 100User
objects. -
Iterates
PaginatedResult
in batches of 100 items. Successive iterations continue until all of the objects retrieved by the query are processed.
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