How to correctly update a org.springframework.data.domain.Page's list?-CodePudding

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 ????;

CodePudding user response：

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

CodePudding user response：

The standard implementation of Page is immutable, so you have to create a new instance, either using PageImpl or https://docs.spring.io/spring-data/commons/docs/current/api/org/springframework/data/repository/support/PageableExecutionUtils.html. Note that your Page will be somewhat broken, because it doesn't contain the correct number of elements.