io.github.halfweight:spring-data-jpa-cursor-paging

Spring data jpa cursor paging

The spring-data-jpa-cursor-paging Java library allows to easily implement cursor pagination for Spring Boot projects. This is a community-based project, not maintained by the Spring Framework Contributors (Pivotal)

Cursor pagination

Usage

1. Add the following dependency

   <groupId>io.github.halfweight</groupId>
   <artifactId>spring-data-jpa-cursor-paging</artifactId>
   <version>last-version</version>
   

2. Configure the repository base class to be used to create repository proxies for this particular configuration

   @EnableJpaRepositories(repositoryBaseClass = CustomRepositoryImpl.class)
   

3. Create a jpa repository that extends the CustomRepository

   public interface UserRepository extends CustomRepository<User, Long> {
   
   }
   

4. Use the created repository and call findAllBy to execute cursor pagination.

   The first parameter is a specification to filter for.

   The second parameter is a CursorPageRequest. For the first query, you have to fill the size and sort fields.

   From the second query onwards make sure to provide the continuationToken

    userRepository.findAllBy(null, CursorPageRequest.of(1, Sort.by(Sort.Order.desc("id"))))
   

   This query returns a CursorPaginationSlice that contains

   field	description
   content	list of found rows
   hasNext	if there are other elements
   continuationToken	token to use to execute the next query. Keep in mind that it changes for every query
   size	size of content

   You can use every field in your entity to sort, but keep in mind that :

   • When you use the continuationToken you have to use always the same sort fields

   • Be sure to use always a unique field as a sorting field for your query as the last parameter (for example the column id)

Customization

To convert values to strings and vice-versa the library uses the ConvertUtils from it.halfweight.spring.cursor.pagination.jpa.util. This is useful to store information into the continuationToken.

If in your entity you are using a not mapped type you would use to sort, you can add a custom converter in this way:

ConverterUtil.config(Map.of(Instant.class,new AbstractConverter() {

@Override
protected <T> T convertToType(Class<T> type, Object value) throws Throwable {
     return (T) Instant.ofEpochMilli(Long.parseLong((String) value));
     }

@Override
protected String convertToString(Object value) throws Throwable {
     return Long.toString(((Instant)value).toEpochMilli());
     }

@Override
protected Class<?> getDefaultType() {
     return Instant.class;
 }
}));

Contributing

Pull requests are welcome. For major changes, please open an issue first to discuss what you would like to change.

Please make sure to update tests as appropriate.