BAEL-3091: The Prototype Pattern in Java (changed code based on valid comments from a reader)

persistence-modules/spring-data-jpa-3/src/main/java/com/baeldung/Application.java

@@ -0,0 +1,12 @@
+package com.baeldung;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class Application {
+
+    public static void main(String[] args) {
+        SpringApplication.run(Application.class, args);
+    }
+}

persistence-modules/spring-data-jpa-3/src/main/java/com/baeldung/tx/Payment.java

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+package com.baeldung.tx;
+
+import javax.persistence.*;
+
+@Entity
+public class Payment {
+
+    @Id
+    @GeneratedValue
+    private Long id;
+
+    private Long amount;
+
+    @Column(unique = true)
+    private String referenceNumber;
+
+    @Enumerated(EnumType.STRING)
+    private State state;
+
+    public Long getId() {
+        return id;
+    }
+
+    public void setId(Long id) {
+        this.id = id;
+    }
+
+    public Long getAmount() {
+        return amount;
+    }
+
+    public void setAmount(Long amount) {
+        this.amount = amount;
+    }
+
+    public String getReferenceNumber() {
+        return referenceNumber;
+    }
+
+    public void setReferenceNumber(String referenceNumber) {
+        this.referenceNumber = referenceNumber;
+    }
+
+    public State getState() {
+        return state;
+    }
+
+    public void setState(State state) {
+        this.state = state;
+    }
+
+    public enum State {
+        STARTED, FAILED, SUCCESSFUL
+    }
+}

persistence-modules/spring-data-jpa-3/src/test/java/com/baeldung/tx/ManualTransactionIntegrationTest.java

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+package com.baeldung.tx;
+
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.autoconfigure.jdbc.AutoConfigureTestDatabase;
+import org.springframework.boot.test.autoconfigure.orm.jpa.DataJpaTest;
+import org.springframework.test.context.ActiveProfiles;
+import org.springframework.transaction.PlatformTransactionManager;
+import org.springframework.transaction.TransactionDefinition;
+import org.springframework.transaction.TransactionStatus;
+import org.springframework.transaction.annotation.Transactional;
+import org.springframework.transaction.support.DefaultTransactionDefinition;
+import org.springframework.transaction.support.TransactionCallbackWithoutResult;
+import org.springframework.transaction.support.TransactionTemplate;
+import org.testcontainers.containers.PostgreSQLContainer;
+import org.testcontainers.junit.jupiter.Container;
+import org.testcontainers.junit.jupiter.Testcontainers;
+
+import javax.persistence.EntityManager;
+
+import static java.util.Collections.singletonList;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.springframework.boot.test.autoconfigure.jdbc.AutoConfigureTestDatabase.Replace.NONE;
+import static org.springframework.transaction.annotation.Propagation.NOT_SUPPORTED;
+
+@DataJpaTest
+@Testcontainers
+@ActiveProfiles("test")
+@AutoConfigureTestDatabase(replace = NONE)
+@Transactional(propagation = NOT_SUPPORTED)
+class ManualTransactionIntegrationTest {
+
+    @Container
+    private static PostgreSQLContainer<?> pg = initPostgres();
+
+    @Autowired
+    private PlatformTransactionManager transactionManager;
+
+    @Autowired
+    private EntityManager entityManager;
+
+    private TransactionTemplate transactionTemplate;
+
+    @BeforeEach
+    void setUp() {
+        transactionTemplate = new TransactionTemplate(transactionManager);
+    }
+
+    @AfterEach
+    void flushDb() {
+        transactionTemplate.execute(status -> entityManager
+                .createQuery("delete from Payment")
+                .executeUpdate());
+    }
+
+    @Test
+    void givenAPayment_WhenNotDuplicate_ThenShouldCommit() {
+        Long id = transactionTemplate.execute(status -> {
+            Payment payment = new Payment();
+            payment.setAmount(1000L);
+            payment.setReferenceNumber("Ref-1");
+            payment.setState(Payment.State.SUCCESSFUL);
+
+            entityManager.persist(payment);
+
+            return payment.getId();
+        });
+
+        Payment payment = entityManager.find(Payment.class, id);
+        assertThat(payment).isNotNull();
+    }
+
+    @Test
+    void givenAPayment_WhenMarkAsRollback_ThenShouldRollback() {
+        transactionTemplate.execute(status -> {
+            Payment payment = new Payment();
+            payment.setAmount(1000L);
+            payment.setReferenceNumber("Ref-1");
+            payment.setState(Payment.State.SUCCESSFUL);
+
+            entityManager.persist(payment);
+            status.setRollbackOnly();
+
+            return payment.getId();
+        });
+
+        assertThat(entityManager
+                .createQuery("select p from Payment p")
+                .getResultList()).isEmpty();
+    }
+
+    @Test
+    void givenTwoPayments_WhenRefIsDuplicate_ThenShouldRollback() {
+        try {
+            transactionTemplate.execute(s -> {
+                Payment first = new Payment();
+                first.setAmount(1000L);
+                first.setReferenceNumber("Ref-1");
+                first.setState(Payment.State.SUCCESSFUL);
+
+                Payment second = new Payment();
+                second.setAmount(2000L);
+                second.setReferenceNumber("Ref-1");
+                second.setState(Payment.State.SUCCESSFUL);
+
+                entityManager.persist(first);
+                entityManager.persist(second);
+
+                return "Ref-1";
+            });
+        } catch (Exception ignored) {
+        }
+
+        assertThat(entityManager
+                .createQuery("select p from Payment p")
+                .getResultList()).isEmpty();
+    }
+
+    @Test
+    void givenAPayment_WhenNotExpectingAnyResult_ThenShouldCommit() {
+        transactionTemplate.execute(new TransactionCallbackWithoutResult() {
+            @Override
+            protected void doInTransactionWithoutResult(TransactionStatus status) {
+                Payment payment = new Payment();
+                payment.setReferenceNumber("Ref-1");
+                payment.setState(Payment.State.SUCCESSFUL);
+
+                entityManager.persist(payment);
+            }
+        });
+
+        assertThat(entityManager
+                .createQuery("select p from Payment p")
+                .getResultList()).hasSize(1);
+    }
+
+    @Test
+    void givenAPayment_WhenUsingTxManager_ThenShouldCommit() {
+        DefaultTransactionDefinition definition = new DefaultTransactionDefinition();
+        definition.setIsolationLevel(TransactionDefinition.ISOLATION_REPEATABLE_READ);
+        definition.setTimeout(3);
+
+        TransactionStatus status = transactionManager.getTransaction(definition);
+        try {
+            Payment payment = new Payment();
+            payment.setReferenceNumber("Ref-1");
+            payment.setState(Payment.State.SUCCESSFUL);
+
+            entityManager.persist(payment);
+            transactionManager.commit(status);
+        } catch (Exception ex) {
+            transactionManager.rollback(status);
+        }
+
+        assertThat(entityManager
+                .createQuery("select p from Payment p")
+                .getResultList()).hasSize(1);
+    }
+
+    private static PostgreSQLContainer<?> initPostgres() {
+        PostgreSQLContainer<?> pg = new PostgreSQLContainer<>("postgres:11.1")
+                .withDatabaseName("baeldung")
+                .withUsername("test")
+                .withPassword("test");
+        pg.setPortBindings(singletonList("54320:5432"));
+
+        return pg;
+    }
+}

persistence-modules/spring-data-jpa-3/src/test/resources/application-test.properties

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+spring.jpa.hibernate.ddl-auto=update
+spring.datasource.url=jdbc:postgresql://localhost:54320/baeldung
+spring.datasource.username=test
+spring.datasource.password=test