implements optimistic locking for PackageEntity

src/main/java/net/hostsharing/hsadminng/hs/hspackage/PackageEntity.java

@@ -19,6 +19,9 @@ public class PackageEntity {
 
     private @Id UUID uuid;
 
+    @Version
+    private int version;
+
     @ManyToOne(optional = false)
     @JoinColumn(name = "customeruuid")
     private CustomerEntity customer;

src/main/resources/db/changelog/2022-07-29-070-hs-package.sql

@@ -7,6 +7,7 @@
 create table if not exists package
 (
     uuid         uuid unique references RbacObject (uuid),
+    version      int not null default 0,
     customerUuid uuid references customer (uuid),
     name         varchar(5),
     description  varchar(96)

src/test/java/net/hostsharing/hsadminng/hs/hspackage/PackageRepositoryIntegrationTest.java

@@ -2,11 +2,13 @@ package net.hostsharing.hsadminng.hs.hspackage;
 
 import net.hostsharing.hsadminng.context.Context;
 import net.hostsharing.hsadminng.hs.hscustomer.CustomerRepository;
+import net.hostsharing.test.JpaAttempt;
 import org.junit.jupiter.api.Nested;
 import org.junit.jupiter.api.Test;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.test.autoconfigure.orm.jpa.DataJpaTest;
 import org.springframework.context.annotation.ComponentScan;
+import org.springframework.orm.ObjectOptimisticLockingFailureException;
 import org.springframework.orm.jpa.JpaSystemException;
 import org.springframework.test.annotation.DirtiesContext;
 import org.springframework.transaction.annotation.Transactional;
@@ -18,7 +20,7 @@ import static net.hostsharing.test.JpaAttempt.attempt;
 import static org.assertj.core.api.Assertions.assertThat;
 
 @DataJpaTest
-@ComponentScan(basePackageClasses = { Context.class, CustomerRepository.class })
+@ComponentScan(basePackageClasses = { Context.class, CustomerRepository.class, JpaAttempt.class })
 @DirtiesContext
 class PackageRepositoryIntegrationTest {
 
@@ -28,7 +30,11 @@ class PackageRepositoryIntegrationTest {
     @Autowired
     PackageRepository packageRepository;
 
-    @Autowired EntityManager em;
+    @Autowired
+    EntityManager em;
+
+    @Autowired
+    JpaAttempt jpaAttempt;
 
     @Nested
     class FindAllByOptionalNameLike {
@@ -127,6 +133,49 @@ class PackageRepositoryIntegrationTest {
 
     }
 
+    @Nested
+    class OptimisticLocking {
+
+        @Test
+        public void supportsOptimisticLocking() throws InterruptedException {
+            // given
+            hostsharingAdminWithAssumedRole("package#aaa00.admin");
+            final var pac = packageRepository.findAllByOptionalNameLike("%").get(0);
+
+            // when
+            final var result1 = jpaAttempt.transacted(() -> {
+                hostsharingAdminWithAssumedRole("package#aaa00.admin");
+                pac.setDescription("description set by thread 1");
+                packageRepository.save(pac);
+            });
+            final var result2 = jpaAttempt.transacted(() -> {
+                hostsharingAdminWithAssumedRole("package#aaa00.admin");
+                pac.setDescription("description set by thread 2");
+                packageRepository.save(pac);
+                sleep(1500);
+            });
+
+            // then
+            em.refresh(pac);
+            assertThat(pac.getDescription()).isEqualTo("description set by thread 1");
+            assertThat(result1.caughtException()).isNull();
+            assertThat(result2.caughtException()).isInstanceOf(ObjectOptimisticLockingFailureException.class);
+        }
+
+        private void sleep(final int millis) {
+            try {
+                Thread.sleep(millis);
+            } catch (InterruptedException e) {
+                throw new RuntimeException(e);
+            }
+        }
+    }
+
+    private void hostsharingAdminWithAssumedRole(final String assumedRoles) {
+        currentUser("mike@hostsharing.net");
+        assumedRoles(assumedRoles);
+    }
+
     void currentUser(final String currentUser) {
         context.setCurrentUser(currentUser);
         assertThat(context.getCurrentUser()).as("precondition").isEqualTo(currentUser);

src/test/java/net/hostsharing/hsadminng/hs/hspackage/TestPackage.java

@@ -12,6 +12,6 @@ public class TestPackage {
     public static final PackageEntity xxx02 = hsPackage(TestCustomer.xxx, "xxx02");
 
     public static PackageEntity hsPackage(final CustomerEntity customer, final String name) {
-        return new PackageEntity(randomUUID(), customer, name, "initial description of package " + name);
+        return new PackageEntity(randomUUID(), 0, customer, name, "initial description of package " + name);
     }
 }