A utility class that makes it easier to build criteria queries. From within an initializer block of a (usually anonymous) subclass, all operations of the CriteriaBuilder and CriteriaQuery may be called without the need for specifying the target object.

For example:

sessionFactory.inTransaction(session -> {
    List<Book> books
            = new CriteriaDefinition<>(sessionFactory, Book.class) {{
                var book = from(Book.class);
                where(like(book.get(Book_.title), "%Hibernate%"));
                orderBy(desc(book.get(Book_.publicationDate)), asc(book.get(Book_.isbn)));
                book.fetch(Book_.authors);
            }}
            .createSelectionQuery(session)
            .setMaxResults(10)
            .getResultList();
    ...
});

A CriteriaDefinition may even be used to modify a base HQL or criteria query:

sessionFactory.inTransaction(session -> {
    List<Book> books
            = new CriteriaDefinition<>(sessionFactory, Book.class,
                    "from Book left join fetch authors where type = BOOK") {{
                var book = (JpaRoot<Book>) getSelection();
                where(getRestriction(), like(book.get(Book_.title), "%Hibernate%"));
                orderBy(desc(book.get(Book_.publicationDate)), asc(book.get(Book_.isbn)));
            }}
            .createSelectionQuery(session)
            .getResultList();
    ...
});

For queries which don't change between executions, the CriteriaDefinition may be safely built and cached at startup:

// build and cache the query
static final CriteriaQuery<Book> bookQuery =
        new CriteriaDefinition<>(sessionFactory, Book.class) {{
            var book = from(Book.class);
            where(like(book.get(Book_.title), "%Hibernate%"));
            orderBy(desc(book.get(Book_.publicationDate)), asc(book.get(Book_.isbn)));
            book.fetch(Book_.authors);
        }};

...

// execute it in a session
sessionFactory.inTransaction(session -> {
    List<Book> books =
            session.createQuery(bookQuery)
                    .setMaxResults(10)
                    .getResultList();
    ...
});