| Class: |
net.hrider.api.usecases.Pagination.java |
Some of the API collections can be too large to obtain them in a single request.
This happens for example with the employees and the appraisals.
In this cases, the API paginates the result returning only a small part
of results by request.
To navigate through the collection the 'query' parameters used are:
page, to indicate a specific page number, and
pageSize to
indicate the number of elements wanted to be returned per page.
If not specified, the default values are
page 1 and
pageSize 50.
Since the Hrider API follows the
HATEOS principle,
we can navigate the collection using its links
next and
previous without having to worry about
creating the URI for the next or the previous page.
Example:
First create some employees (later we will obtain them in a paginated list):
Link employeesLink = company.getLinks().getEmployees();
service.create(employeesLink, buildEmployee("EMP1", "Employee 1", "[email protected]"));
service.create(employeesLink, buildEmployee("EMP2", "Employee 2", "[email protected]"));
service.create(employeesLink, buildEmployee("EMP3", "Employee 3", "[email protected]"));
Make a paginated query from 2 to 2 employees (
pageSize = 2) and
print each page:
Link link = company.getLinks().getEmployees().addQueryParam("pageSize", "2");
EmployeesCollection collection = service.get(EmployeesCollection.class, link);
int page = 1;
printPage(page++, collection.getEmbedded().getEmployees());
while (collection.getLinks().getNext() != null) {
collection = service.get(EmployeesCollection.class, collection.getLinks().getNext());
printPage(page++, collection.getEmbedded().getEmployees());
}
As seen, using the
next link it is possible go page by page as long as
next is not
null.
The obtained result is the expected: a first page with 2 employees, and a last page with the remaining employee:
Page: 1
ID Code Email Name
------------------- --------- ------------------ ------------------
184916402857051713 EMP1 [email protected] EMPLOYEE 1
184916402968200770 EMP2 [email protected] EMPLOYEE 2
Page: 2
ID Code Email Name
------------------- --------- ------------------ ------------------
184916403059426883 EMP3 [email protected] EMPLOYEE 3
