QueryDSL Utils

Select

Select uses meta information generated by Metafy to bind query values to DTO values.

Example:

QAuthor author = QAuthor.author;
MAuthorDto meta = MAuthorDto.meta;

Select<AuthorDto> select = new Select<>(AuthorDto.class);
select.as(author.id, meta.id);
select.as(author.name, meta.name);

JPAQuery<AuthorDto> query = new JPAQuery<>(em);
query.from(author);

List<AuthorDto> authors = query.select(select).fetch();

Using converters:

QAuthor author = QAuthor.author;
MAuthorDto meta = MAuthorDto.meta;

Select<AuthorDto> select = new Select<>(AuthorDto.class);
select.as(author.id, meta.id);
select.as(author.name, meta.name, name -> name + "_converted-name");

JPAQuery<AuthorDto> query = new JPAQuery<>(em);
query.from(author);

List<AuthorDto> authors = query.select(select).fetch();

QueryWrapper

Adds utilities to the Query.

Paging example:

QAuthor author = QAuthor.author;
MAuthorDto meta = MAuthorDto.meta;

Select<AuthorDto> select = new Select<>(AuthorDto.class);
select.as(author.id, meta.id);
select.as(author.name, meta.name);

JPAQuery<AuthorDto> query = new JPAQuery<>(em);
query.from(author);
query.select(select);

QueryWrapper<AuthorDto, JPAQuery<AuthorDto>> wrapper = QueryWrapper.wrap(query);

PageSpec pageSpec = new PageSpec(0, 1, null);

PageResult<AuthorDto> result = wrapper.fetchPage(pageSpec);