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Quick Start

Setup

Define your JPA entities and repositories as usual:

@Entity
class User(
    @Id val id: Long,
    val name: String,
    val age: Int,
    val email: String?,
    val role: String,
    val isActive: Boolean
)

interface UserRepository : JpaRepository<User, Long>, JpaSpecificationExecutor<User>

No additional configuration is needed. The DSL is available as soon as the dependency is on the classpath.

Three DSL flavors

The library provides the same operations across three layers depending on what you want to return:

DSL Returns Use when
Specification DSL Specification<T> You use JpaSpecificationExecutor
PredicateSpecification DSL PredicateSpecification<T> You want query-independent conditions (Spring Data JPA 4.x), passed to JpaSpecificationExecutor or reused in Specification, UpdateSpecification and DeleteSpecification
Predicate DSL Predicate You need a raw predicate inside a custom Specification {} block

Your first query

// Single condition
val activeUsers = User::isActive.equal(true)
repository.findAll(activeUsers)

// Combined conditions
val activeAdults = User::isActive.equal(true) and User::age.greaterThan(18)
repository.findAll(activeAdults)

// Reusable specs
fun activeUsers() = User::isActive.equal(true)
fun adults() = User::age.greaterThan(18)

repository.findAll(activeUsers() and adults())

Next steps