Eclipse RCP/RAP and Remoting with JAX-RS, Spring Data JPA and CXF DOSGi [step3]

In [step2] we have implemented the JAX-RS Client which consumes the UserService#findAll() with JAX-RS:

@Path("/user")
public interface UserService {

	@GET
	@Path("/findAll")
	@Produces(MediaType.APPLICATION_JSON)
	Collection<User> findAll();
...
}

We have seen that JAX-RS Client fails when UserService#findAll(Pageable pageable) is called, because we have not annoted this method with JAX-RS:

1031 [Thread-5] ERROR org.apache.cxf.jaxrs.client.ClientProxyImpl  - Method fr.opensagres.services.UserService.findAll is not a valid resource method
	at org.apache.cxf.jaxrs.client.ClientProxyImpl.reportInvalidResourceMethod(ClientProxyImpl.java:546)

In this article we wish to export and import with JAX-RS the UserService#findAll(Pageable pageable) which returns the paginated list of the User which uses Spring Data – Commons structures :

• Pageable : this parameter is the pagination request.
• Page: the findAll method returns this structure which is the result of the pagination.

On other words we will annotate the UserService#findAll(Pageable pageable) like this :

@POST
@Path("/findAllPage")
@Consumes({ MediaType.APPLICATION_JSON })
@Produces({ MediaType.APPLICATION_JSON })
Page<User> findAll(Pageable pageable);

However when I have managed JAX-RS with Spring Data structure, I had 2 big problems coming from :

• Spring Data – Commons: Spring Data Page and Pageable are interfaces and not Pojo. JAX-RS works with Pojo which are annotated with JAXB annotations. How do manage Spring Data Page and Pageable interfaces with JAX-RS? Fortunately, JAXB 2.0 provides XmlJavaTypeAdapter (please read Using JAXB 2.0’s XmlJavaTypeAdapter) which gives the capability to serialize Page and Pageable interfaces with JAXB. I have suggested this idea to Oliver Gierke, the lead of the Spring Data and he is developing JAXB Adapter with SpringDataJaxb.java. However in this article we will not use this class (because this class is not finished) but we will create our own JAXB adapter which will be more simply to understand how to work the JAXB Adapter.
• Apache CXF: on server side when CXF tries to serialize the Page class with JAXB, it fails because the JAXBContext doesn’t know the User class. This problem comes from that CXF is not able to populate the JAXBContext automaticly with Parameterized class (in our case , we have Page<T> and T=User, the JAXBContext is filled just with Page but not with User). You can fix the problem by setting extra class to the JSONProvider :

  <bean id="jsonProvider" class="org.apache.cxf.jaxrs.provider.JSONProvider">
  	<property name="singleJaxbContext" value="true" />
  	<property name="extraClass">
  		<list>
  			<value>fr.opensagres.domain.User</value>
  		</list>
  	</property>
  </bean>
  

  We will do that in this article, but I have created the patch CXF-4359 which fixes the explained problem below to avoid declaring extra classes for JSONProvider.

Eclipse RCP/RAP with Spring DM, Spring Data JPA and Remoting [step9]

In [step8] we have developed a Rich Client with RCP Application to display User list in a SWT Table by consuming the UserService by using Spring DM by using the SpringExtensionFactory from Martin Lippert.

In this article we will display the User List with pagination by using Nebula Pagination Control.

The sort of column will be done by the UserService by using Spring Data Sort Structure:

Eclipse RCP/RAP with Spring DM, Spring Data JPA and Remoting [step8]

In [step7] we have seen how to use Spring Data JPA to add custom methods to the Dao to manage criteria and pagination.

In this article we will implement a Rich Client with RCP Application to display User list in a SWT Table :

We will see how to we can consume the UserService by using Spring DM by using the SpringExtensionFactory from Martin Lippert.

Eclipse RCP/RAP with Spring DM, Spring Data JPA and Remoting [step7]

In [step6] we have implemented the API Dao UserDao with JPA by using Spring Data JPA :

• the API Dao fr.opensagres.dao.UserDao extends the Spring Data org.springframework.data.repository.PagingAndSortingRepository.
• the JPA User Dao implementation is created on runtime by Spring Data JPA by declaring a jpa:repository:

  <!-- Spring Data JPA-->
  <jpa:repositories base-package="fr.opensagres.dao">
    <jpa:repository id="userDao" />
  </jpa:repositories>
  

At this step the UserDao provides the CRUD methods and pagination methods for User entity like :

• Iterable findAll(): to find all entity.
• T save(T model): to save an entity.
• Page findAll(Pageable pageable): to find all entity with pagination.

With Spring Data JPA, it’s possible to add your own method to manage search entities by criteria : to do that the method name of the UserDao must just follow some convention name (see Query creation for more information). In this article we will add the 2 following methods to the UserDao :

• findByFirstNameLikeAndLastNameLike to retrieve a list of User by first name (like) and last name (like):

  List<User> findByFirstNameLikeAndLastNameLike(String firstName,	String lastName);
  

• findByFirstNameLikeAndLastNameLike to retrieve a list of User by first name (like) and last name (like) with pagination:

  Page<User> findByFirstNameLikeAndLastNameLike(String firstName,	String lastName, Pageable pageable);
  

Just add those 2 methods to UserDao API and Spring Data JPA will manage for you the JPA implementation!

Eclipse RCP/RAP with Spring DM, Spring Data JPA and Remoting [step6]

In [step5] we have prepared the Target Platform with:

• The JPA API.
• EclipseLink used as JPA Implementation
• Derby used as Database.
• Commons DBCP used as connection pool.
• Spring Data JPA to implement our DAO with JPA.

The API Dao fr.opensagres.dao.UserDao extends the Spring Data org.springframework.data.repository.PagingAndSortingRepository interface which is the first step to use Spring Data JPA.

In this article we will create several bundles/fragment to retrieves User list from a Database Derby with EclipseLink JPA. The JPA Dao implementation will be done with Spring Data JPA, on other words, you will do nothing (no need to code a JPAUserDao class). We will create 2 bundles and 1 fragment :

• fr.opensagres.dao.jpa the bundle implementation of UserDao with JPA by using Spring Data JPA to avoid coding the JPAUserDao class.
• fr.opensagres.dao.jpa.eclipselink the fragment which configures the JPA fr.opensagres.dao.jpa to use EclipseLink and Deby as dialect.
• fr.opensagres.data.datasource the bundle which publishes the Derby Datasource used by the fr.opensagres.dao.jpa.