Implement Specification as enum

build.gradle.kts

@@ -29,6 +29,7 @@ dependencies {
         "org.springframework.boot:spring-boot-starter-web",
         "org.springframework.boot:spring-boot-starter-validation",
         "org.springframework.boot:spring-boot-starter-webflux",
+        "org.springframework.boot:spring-boot-starter-data-jpa",
         "com.google.guava:guava:33.4.0-jre",
         "com.google.code.gson:gson:2.11.0"
     ).forEach { implementation(it) }

src/main/java/org/test/criteria/Customer.java

@@ -0,0 +1,9 @@
+package org.test.criteria;
+
+import lombok.Data;
+
+@Data
+public class Customer {
+
+    private final Class<?> typeTocken;
+}

src/main/java/org/test/criteria/CustomerRepository.java

@@ -0,0 +1,15 @@
+package org.test.criteria;
+
+import org.springframework.data.jpa.domain.Specification;
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.data.jpa.repository.JpaSpecificationExecutor;
+import org.springframework.lang.Nullable;
+
+import java.util.List;
+import java.util.UUID;
+
+public interface CustomerRepository
+        extends JpaRepository<Customer, UUID>, JpaSpecificationExecutor<Customer> {
+
+    List<Customer> findAll(@Nullable Specification<Customer> customerSpecification);
+}

src/main/java/org/test/criteria/CustomerService.java

@@ -0,0 +1,23 @@
+package org.test.criteria;
+
+import org.springframework.beans.factory.annotation.Autowired;
+
+import java.util.List;
+
+import static org.springframework.data.jpa.domain.Specification.where;
+import static org.test.criteria.CustomerSpecifications.CUSTOMER_HAS_BIRTHDAY;
+import static org.test.criteria.CustomerSpecifications.IS_LONG_TERM_CUSTOMER;
+
+public class CustomerService {
+
+    private final CustomerRepository repository;
+
+    @Autowired
+    public CustomerService(CustomerRepository repository) {
+        this.repository = repository;
+    }
+
+    public List<Customer> nothing() {
+        return repository.findAll(where(CUSTOMER_HAS_BIRTHDAY).and(IS_LONG_TERM_CUSTOMER));
+    }
+}

src/main/java/org/test/criteria/CustomerSpecifications.java

@@ -0,0 +1,34 @@
+package org.test.criteria;
+
+import javax.persistence.criteria.CriteriaBuilder;
+import javax.persistence.criteria.CriteriaQuery;
+import javax.persistence.criteria.Predicate;
+import javax.persistence.criteria.Root;
+import org.springframework.data.jpa.domain.Specification;
+
+import java.time.LocalDate;
+
+enum CustomerSpecifications implements Specification<Customer> {
+
+    CUSTOMER_HAS_BIRTHDAY {
+        @Override
+        public Predicate toPredicate(Root<Customer> root,
+                                     CriteriaQuery<?> query,
+                                     CriteriaBuilder criteriaBuilder) {
+            var birthday = root.<LocalDate>get("birthday");
+            var today = LocalDate.now();
+            return criteriaBuilder.equal(birthday, today);
+        }
+    },
+
+    IS_LONG_TERM_CUSTOMER {
+        @Override
+        public Predicate toPredicate(Root<Customer> root,
+                                     CriteriaQuery<?> query,
+                                     CriteriaBuilder criteriaBuilder) {
+            var createdAt1 = root.<LocalDate>get("createdAt");
+            var twoYearsFromNow = LocalDate.now().minusYears(2);
+            return criteriaBuilder.lessThan(createdAt1, twoYearsFromNow);
+        }
+    }
+}

src/main/java/org/test/criteria/package-info.java

@@ -0,0 +1,6 @@
+@NonNullApi
+@CheckReturnValue
+package org.test.criteria;
+
+import com.google.errorprone.annotations.CheckReturnValue;
+import org.springframework.lang.NonNullApi;