Searching using Criteria Query JPA Spring

Question

AssetItemDto has the fields name and code, I want to findAll the records in the DB that matches any of the below conditions

1. FindAll where name = "A" and code = "B" (in case name and code are both there and are not null)
2. FindAll where name = "A" (in case name is there and code is null ) and vice versa.

How can I achieve the same using Criteria Query filling up the below function.

AssetItemDto
            
private String name;
private String code;

// Function I am using: 

Page<AssetItemDto> assetItemPage = assetItemService.findByCondition(assetItemDto,pageable);
                   
public Page<AssetItemDto> findByCondition(AssetItemDto assetItemDto , Pageable pageable) {
            
Page<AssetItem> entityPage = repository.findAll(assetItemDto,pageable);
                    List<AssetItem> entities = entityPage.getContent();
            
return new PageImpl<>(mapList(entities, AssetItemDto.class), pageable, entityPage.getTotalElements());
}

Answer 1

You can use the @Query annotation at the top of a repository method for writing a custom query to the database table. Here's a sample according to your conditions. You can modify the method name and the table name accordingly.

    @Query("""
        SELECT * 
        FROM AssetItemDto
        where (name = 'A' AND code = 'B') OR (name = 'A' AND code IS NULL) OR (name IS NULL AND code = 'B');
""")
    List<AssetItemDto> findAllByCustomCondition();

Answer 2

Are you looking for something like this?

Page<AssetItemEntity> findByCondition(String name, String code, Pageable pageable) {

    Specification<AssetItemEntity> spec = (root, query, builder) ->
        builder.or(
            builder.equal(root.get("name"), root.get("code")),
            builder.or(
                builder.and(
                    builder.isNull(root.get("name")),
                    builder.equal(root.get("code"), code)
                ),
                builder.and(
                    builder.isNull(root.get("code")),
                    builder.equal(root.get("name"), name)
                )
            )
        );

    return assetItemRepository.findAll(spec, pageable);
}