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I'm want to create a specification that matches a group id of a user object against a list of ids. I was thinking about using isMember (like in the code) but the method won't take the list.
public static Specification<User> matchCompanyIdsList(final List<Long> groupIds){ return new Specification<User>() { public Predicate toPredicate(Root<User> root, CriteriaQuery<?> query, CriteriaBuilder builder){ final Path<Group> group = root.<Group> get("group"); return builder.isMember(company.<Long>get("id"), companyIds); } }; } If I'm off, the how would I do it otherwise?
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Specifications provide us with a way to write reusable queries and also fluent APIs with which we can combine and build more sophisticated queries. All in all, Spring JPA Specifications is a great tool whether we want to create reusable predicates or want to generate typesafe queries programmatically.
Java Prime Pack The Criteria API is a predefined API used to define queries for entities. It is the alternative way of defining a JPQL query. These queries are type-safe, and portable and easy to modify by changing the syntax. Similar to JPQL it follows abstract schema (easy to edit schema) and embedded objects.
Spring Data JPA is not an implementation or JPA provider, it's just an abstraction used to significantly reduce the amount of boilerplate code required to implement data access layers for various persistence stores.
The @Query annotation takes precedence over named queries, which are annotated with @NamedQuery or defined in an orm. xml file. It's a good approach to place a query definition just above the method inside the repository rather than inside our domain model as named queries.
Do you want to create a specification that matches all users that have group id, which are in the groupsIds list?
If so, you could use something like this (Which will use SQL IN clause):
public static Specification<User> matchCompanyIdsList(final List<Long> groupIds){ return new Specification<User>() { public Predicate toPredicate(Root<User> root, CriteriaQuery<?> query, CriteriaBuilder builder){ final Path<Group> group = root.<Group> get("group"); return group.in(groupIds); } }; } If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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