I'm using Spring data JPA. I have a situation where my database identity is a surrogate key which returns three records, but I have implemented the equals method to reduce the collection down to two names. How to update the Page<Person> byName after filtering out / removing records from it at the service layer?
Example:
ID license Name 1 123456 Kim Kardashian 2 123456 Kim Kardashian West 3 123456 Kim Kardashian When searching I want to return two records. I have overridden the equals and hashcode method to define equality based on the, license and name attributes. I'm okay with it arbitrarily picking 1 or 3 to represent the 123456 Kim Kardashian record.
ID license Name 1 123456 Kim Kardashian 2 123456 Kim Kardashian West Code snippet of the repository returning the 3 records, and now at the service layer I would like to filter it down to the two records.
Page<Person> byName = PersonRepository.findByName( name, pageable); //Now remove duplicates based on the equals() method rather than database identity (this is a read-only entity. List<Person> collect = byName.get().distinct().collect(Collectors.toList()); //how to place the replace the list back in the byName and the paging information is accurate? return ????; 2 Answers
You can use this utility method
import org.springframework.data.domain.PageImpl; import org.springframework.data.domain.PageRequest; public static <T> Page<T> toPage(List<T> list, int pageNumber, int pageSize, int totalRecords) { PageRequest pageable = PageRequest.of(pageNumber, pageSize); return new PageImpl<>(list, pageable, totalRecords); } pageNumber starts from 0
The standard implementation of Page is immutable, so you have to create a new instance, either using PageImpl or . Note that your Page will be somewhat broken, because it doesn't contain the correct number of elements.
