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Source: https://spring.io/projects/spring-data-jpa
Spring and EclipseLink
By default Spring uses Hibernate as the default JPA vendor. Although Hibernate is a good choice, someone may prefers to use EclipseLink as it was supposed to be the reference implementation for the Java Persistence JSR.
How configuring Spring-Boot to use EclipseLink as the JPA provider: https://blog.marcnuri.com/spring-data-jpa-eclipselink-configuring-spring-boot-to-use-eclipselink-as-the-jpa-provider/
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import javax.persistence.Column; import javax.persistence.ElementCollection; import javax.persistence.EmbeddedId; import javax.persistence.Entity; import javax.persistence.Inheritance; import javax.persistence.InheritanceType; import javax.persistence.Table; @Entity @Table(name = "ToscaProperty") @Inheritance(strategy = InheritanceType.TABLE_PER_CLASS) @Data @EqualsAndHashCode(callSuper = false) public class JpaToscaProperty extends PfConcept implements PfAuthorative<ToscaProperty> { private static final long serialVersionUID = 1675770231921107988L; @EmbeddedId @VerifyKey @NotNull private PfReferenceKey key; @Column @VerifyKey @NotNull private PfConceptKey type; @Column @NotBlank private String description; |
Spring Repository
Using With Spring Data JPA it needs , is a good choice to implement a repository for each modelrepositories.
The goal of Spring Data repository abstraction is to significantly reduce the amount of boilerplate code required to implement data access layers for various persistence stores.
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@ExtendWith(SpringExtension.class) @DataJpaTest @Import(value = ParticipantPolicyParameters.class) @TestPropertySource(locations = {"classpath:application_test.properties"}) class JpaToscaPropertyRepositoryTest { @Autowired private JpaToscaPropertyRepository toscaPropertyRepository; @Test void test() { JpaToscaProperty toscaProperty = new JpaToscaProperty(); PfReferenceKey key = toscaProperty.getKey(); Map<String, String> metadata = new HashMap<>(); metadata.put("Key", "Value"); metadata.put("K", "V"); List<JpaToscaConstraint> constraints = new ArrayList<>(); String[] list = new String[] {"First", "Second"}; constraints.add(new JpaToscaConstraintValidValues(Stream.of(list).collect(Collectors.toList()))); toscaProperty.setDefaultValue("DefaultValue"); toscaProperty.setDescription("Description"); toscaProperty.setRequired(true); toscaProperty.setStatus(ToscaProperty.Status.EXPERIMENTAL); toscaProperty.setMetadata(metadata); toscaProperty.setConstraints(constraints); toscaPropertyRepository.save(toscaProperty); Optional<JpaToscaProperty> opt = toscaPropertyRepository.findById(key); assertThat(opt).isNotEmpty(); JpaToscaProperty actual = opt.get(); assertThat(actual.getDefaultValue()).isEqualTo(toscaProperty.getDefaultValue()); assertThat(actual.getDescription()).isEqualTo(toscaProperty.getDescription()); assertThat(actual.isRequired()).isEqualTo(toscaProperty.isRequired()); assertThat(actual.getStatus()).isEqualTo(toscaProperty.getStatus()); assertThat(actual.getType()).isEqualTo(toscaProperty.getType()); assertThat(actual.getConstraints()).isEqualTo(toscaProperty.getConstraints()); } } |
Using Dao
There Dao objects are already implemented in Policy Framework, and there is a way to use the whole Policy Framework implementation. them and avoid to create repositories, but It needs to create a new DefaultPfDao class that uses the Entity Manger with no "begin transaction" and no "commit".
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@Service public class ControlLoopInstantiationProvider { private final ControlLoopProvider controlLoopProvider; private final CommissioningProvider commissioningProvider; /** * Create a instantiation provider. * * @param databaseProviderParameters the parameters for database access */ public ControlLoopInstantiationProvider(ControlLoopProvider controlLoopProvider, CommissioningProvider commissioningProvider) { this.controlLoopProvider = controlLoopProvider; this.commissioningProvider = commissioningProvider; } @Transactional public InstantiationResponse createControlLoops(ControlLoops controlLoops) throws PfModelException { for (ControlLoop controlLoop : controlLoops.getControlLoopList()) { ControlLoop checkControlLoop = controlLoopProvider.getControlLoop(controlLoop.getKey().asIdentifier()); if (checkControlLoop != null) { throw new PfModelException(Response.Status.BAD_REQUEST, controlLoop.getKey().asIdentifier() + " already defined"); } } BeanValidationResult validationResult = validateControlLoops(controlLoops); if (!validationResult.isValid()) { throw new PfModelException(Response.Status.BAD_REQUEST, validationResult.getResult()); } controlLoopProvider.createControlLoops(controlLoops.getControlLoopList()); InstantiationResponse response = new InstantiationResponse(); response.setAffectedControlLoops(controlLoops.getControlLoopList().stream() .map(cl -> cl.getKey().asIdentifier()).collect(Collectors.toList())); return response; } |
Transaction
Transaction Propagation in SpringBoot:
- REQUIRED is the default propagation. Spring checks if there is an active transaction, then it creates a new one if nothing existed;
- For SUPPORTS, Spring first checks if an active transaction exists. If a transaction exists, then the existing transaction will be used. If there isn't a transaction, it is executed non-transactional;
- When the propagation is MANDATORY, if there is an active transaction, then it will be used. If there isn't an active transaction, then Spring throws an exception;
- For transactional logic with NEVER propagation, Spring throws an exception if there's an active transaction;
- NOT_SUPPORTED, Spring at first suspends the current transaction if it exists, then the business logic is executed without a transaction;
- When the propagation is REQUIRES_NEW, Spring suspends the current transaction if it exists and then creates a new one.
Read only Transaction
If the transaction is effectively read-only, it allows for corresponding optimizations at runtime. (https://stackoverflow.com/questions/1614139/spring-transactional-read-only-propagation)
Note: In Spring, @Transactional
works by creating a proxy of the class and intercepting the annotated method (AOP Proxies). This means that @Transactional
doesn't work if you are calling the annotated method from another method of the same class.
Other links
- https://gerrit.nordix.org/c/local/onap/clamp-pilot/+/8929
- https://docs.spring.io/spring-boot/docs/current/reference/htmlsingle/
- https://docs.spring.io/spring-framework/docs/current/reference/html/
- https://www.adam-bien.com/roller/abien/entry/jpa_ejb3_killed_the_dao
- https://www.adam-bien.com/roller/abien/entry/daos_aren_t_dead_but
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