Java EntityGraph类代码示例

import javax.persistence.EntityGraph; //导入依赖的package包/类
/**
 * Fetches an instance of given PhoneBookEntry with all lazy 
 * loaded properties loaded.
 * @param entry
 * @return the fully loaded instance
 */
public PhoneBookEntry loadFully(PhoneBookEntry entry) {
    // To get lazy loaded fields initialized, you have couple of options,
    // all with pros and cons, 3 of them presented here.

    // 1) use an explicit join query (with EntityManager or @Query annotation
    //    in repository method.
    //    em.createQuery("select e from PhoneBookEntry e LEFT JOIN FETCH e.groups where e.id = :id", PhoneBookEntry.class);
    //    ...
    // 2) use EntityGraph's introduced in JPA 2.1, here constructed dynamically
    //    and passed via QueryResult object from DeltaSpike Data. You can 
    //    also use entity graphs with @Query annotation in repositories or
    //    with raw EntityManager API.
    EntityGraph<PhoneBookEntry> graph = this.em.createEntityGraph(
            PhoneBookEntry.class);
    graph.addSubgraph("groups");
    entry = entryRepo.findById(entry.getId())
            .hint("javax.persistence.loadgraph", graph)
            .getSingleResult();

    // 3) ..or use the infamous size() hack that all of us actually do :-)
    entry.getAddresses().size();

    return entry;
}
 

import javax.persistence.EntityGraph; //导入依赖的package包/类
private static void addAttributeNodes(String fieldName, EntityGraph<?> graph) {
    int pos = fieldName.indexOf(GRAPH_DELIMETER);
    if (pos < 0) {
        graph.addAttributeNodes(fieldName);
        return;
    }

    String subgraphName = fieldName.substring(0, pos);
    Subgraph<?> subGraph = graph.addSubgraph(subgraphName);
    String nextFieldName = fieldName.substring(pos + 1);
    pos = nextFieldName.indexOf(GRAPH_DELIMETER);

    while (pos > 0) {
        subgraphName = nextFieldName.substring(0, pos);
        subGraph = graph.addSubgraph(subgraphName);
        nextFieldName = nextFieldName.substring(pos + 1);
        pos = nextFieldName.indexOf(GRAPH_DELIMETER);
    }

    subGraph.addAttributeNodes(nextFieldName);
}
 

import javax.persistence.EntityGraph; //导入依赖的package包/类
@Override
public List<E> findAllWithAttributes(String... attributes) {
    //        String sql = "SELECT o FROM " + getTableName() + " o";

    EntityGraph<E> graph = entityManager.createEntityGraph(getEntityClass());
    graph.addAttributeNodes(attributes);

    //        TypedQuery<E> query = entityManager.createQuery(sql, getEntityClass());
    //        query.setHint("javax.persistence.loadgraph", graph);

    //        TypedQuery<E> query = entityManager.createQuery(sql, getEntityClass());
    //        LoadGroup lg = new LoadGroup();
    //        lg.addAttributes(Arrays.asList(attributes));
    //        query.setHint(QueryHints.LOAD_GROUP, lg);
    //        for (String att : attributes) {
    //            query.setHint(QueryHints.BATCH, "o." + att);
    //        }

    //        List<E> result = query.getResultList();
    List<E> result = findAllWithGraph(graph);
    return result;
}
 

import javax.persistence.EntityGraph; //导入依赖的package包/类
@SuppressWarnings("unchecked")
@Test
public void selectWithEntityGraph() {
	log.info("... selectWithEntityGraph ...");

	EntityManager em = emf.createEntityManager();
	em.getTransaction().begin();

	EntityGraph<Author> graph = em.createEntityGraph(Author.class);
	graph.addAttributeNodes(Author_.books);
	
	TypedQuery<Author> q = em.createQuery("SELECT a FROM Author a WHERE a.id = 1", Author.class);
	q.setHint("javax.persistence.fetchgraph", graph);
	Author a = q.getSingleResult();
	
	em.getTransaction().commit();
	em.close();
	
	log.info(a.getFirstName()+" "+a.getLastName()+" wrote "+a.getBooks().size()+" books.");
}
 

import javax.persistence.EntityGraph; //导入依赖的package包/类
@Test
public void selectWithNamedEntityGraph() {
	log.info("... selectWithNamedEntityGraph ...");

	EntityManager em = emf.createEntityManager();
	em.getTransaction().begin();

	EntityGraph<?> graph = em.createEntityGraph("graph.AuthorBooks");
	TypedQuery<Author> q = em.createQuery("SELECT a FROM Author a WHERE a.id = 1", Author.class);
	q.setHint("javax.persistence.fetchgraph", graph);
	Author a = q.getSingleResult();
	
	em.getTransaction().commit();
	em.close();
	
	log.info(a.getFirstName()+" "+a.getLastName()+" wrote "+a.getBooks().size()+" books.");
}
 

import javax.persistence.EntityGraph; //导入依赖的package包/类
/**
 * {@inheritDoc}
 */
@Override
public DocumentRouteHeaderValue getMinimalRouteHeader(String documentId) {
    // This graph is defined on the DocumentRouteHeaderValue class.
    EntityGraph<DocumentRouteHeaderValue> entityGraph =
            (EntityGraph<DocumentRouteHeaderValue>) entityManager.createEntityGraph("DocumentRouteHeaderValue.ActionListAttributesOnly");
    TypedQuery<DocumentRouteHeaderValue> query = entityManager.createQuery("SELECT rh FROM DocumentRouteHeaderValue rh WHERE rh.documentId = :documentId", DocumentRouteHeaderValue.class );
    // By using the graph - all properties but those on the graph should have
    // a lazy proxy in place.  Attempting to access any of those *should* cause the
    // rest of the properties to load.
    query.setHint("javax.persistence.fetchgraph", entityGraph);
    query.setParameter("documentId", documentId);
    List<DocumentRouteHeaderValue> result = query.getResultList();
    if ( result.isEmpty() ) {
        return null;
    }
    return result.get(0);
}
 

import javax.persistence.EntityGraph; //导入依赖的package包/类
/**
 * Suche nach Kunden �ber Nachnamen
 * @param name Der angegebene Nachname
 * @return Liste der Kunden, die den angegebenen Nachnamen besitzen
 */
@NotNull(message = "{kunde.notFound.name}")
public List<Kunde> findKundenByNachname(String name, FetchType fetchType) {
	final TypedQuery<Kunde> query = em.createNamedQuery(Kunde.FIND_KUNDEN_BY_NACHNAME, Kunde.class)
				 					  .setParameter(Kunde.PARAM_KUNDE_NACHNAME, name);
	
	EntityGraph<?> entityGraph;
	switch(fetchType) {
		case NUR_KUNDE:
			break;
				
		case MIT_BESTELLUNGEN:
			entityGraph = em.getEntityGraph(Kunde.GRAPH_BESTELLUNGEN);
			query.setHint(LOADGRAPH, entityGraph);
			break;
			
		default:
			break;
		}
	return query.getResultList();
}
 

import javax.persistence.EntityGraph; //导入依赖的package包/类
/**
 * Suche nach Liste aller Kunden
 * @return Gibt alle vorhandenen Kunden zur�ck
 */
public List<Kunde> findAllKunden(FetchType fetchType, OrderType orderType) {
	final TypedQuery<Kunde> query = OrderType.ID.equals(orderType)
									? em.createNamedQuery(Kunde.FIND_KUNDEN_ORDER_BY_ID, Kunde.class)
									: em.createNamedQuery(Kunde.FIND_KUNDEN, Kunde.class);
	
	EntityGraph<?> entityGraph;
	switch(fetchType) {
		case NUR_KUNDE:
			break;
		
		case MIT_BESTELLUNGEN:
			entityGraph = em.getEntityGraph(Kunde.GRAPH_BESTELLUNGEN);
			query.setHint(LOADGRAPH, entityGraph);
			break;
		
		default:
			break;
	}
	return query.getResultList();
}
 

import javax.persistence.EntityGraph; //导入依赖的package包/类
/**
 * Build or return the default Entity Graph that represents defaultExpand
 *
 * @param session
 *
 * @return
 */
public EntityGraph getDefaultGraph(final Session session)
{
	if (this.defaultExpandGraph == null)
	{
		final EntityGraph<?> graph = session.createEntityGraph(clazz);

		populateGraph(graph, getEagerFetch());

		this.defaultExpandGraph = graph;

		return graph;
	}
	else
	{
		return this.defaultExpandGraph;
	}
}
 

import javax.persistence.EntityGraph; //导入依赖的package包/类
public void init() {
        log.info("call init, id @" + id);
        if (id != null) {
            //this.post = em.find(Post.class, this.id);
            EntityGraph postEntityGraph=em.getEntityGraph("post");
//            EntityGraph postEntityGraph=em.createEntityGraph(Post.class);
//            postEntityGraph.addAttributeNodes("title");
//            postEntityGraph.addSubgraph("comments").addAttributeNodes("content");
            
            this.post=em
                    .createQuery("select p from Post p where p.id=:id", Post.class)
                    .setHint("javax.persistence.loadgraph", postEntityGraph)
                    .setParameter("id", this.id)
                    .getResultList()
                    .get(0);
            
            PersistenceUnitUtil util=em.getEntityManagerFactory().getPersistenceUnitUtil();
            
            log.info("title is [email protected]"+util.isLoaded(this.post, "title"));
            log.info("body is [email protected]"+util.isLoaded(this.post, "body"));
            log.info("comments is [email protected]"+util.isLoaded(this.post, "comments"));
        } else {
            throw new RuntimeException("id is required");
        }
    }
 

import javax.persistence.EntityGraph; //导入依赖的package包/类
@Test
@InSequence(5)
public void shouldLoadArtistWithLiveConcertsAndContracts()
    throws Exception{
    EntityGraph artistGraph = em.getEntityGraph("Artist.WithConcertsAndContracts");
    PersistenceUnitUtil util =
        em.getEntityManagerFactory().getPersistenceUnitUtil();
    Artist artist = getArtistWithEntityGraph(
        "Artist.WithConcertsAndContracts");
    System.out.printf("++++ artist=%s\n", artist);
    assertTrue(util.isLoaded(artist, "id"));
    assertTrue(util.isLoaded(artist, "name"));
    assertTrue(util.isLoaded(artist, "events"));
    ConcertEvent event = artist.getEvents().values().iterator().next();
    System.out.printf("++++ concert event=%s\n", event );
    assertTrue(util.isLoaded(event, "id"));
    assertTrue(util.isLoaded(event, "name"));
    assertTrue(util.isLoaded(event, "eventType"));
    assertTrue(util.isLoaded(event, "contracts"));
}
 

import javax.persistence.EntityGraph; //导入依赖的package包/类
@Test
@InSequence(2)
public void shouldLoadArtistWithoutConcerts() throws Exception{
    PersistenceUnitUtil util =
        em.getEntityManagerFactory().getPersistenceUnitUtil();
    EntityGraph artistGraph = em.getEntityGraph("Artist.NoConcerts");
    Artist artist = (Artist) em.createQuery("Select a from Artist a")
        .setHint("javax.persistence.fetchgraph", artistGraph)
        .getResultList()
        .get(0);
    System.out.printf("++++ artist=%s\n", artist);
    System.out.printf(">> loaded  artist.id = %s\n", util.isLoaded(artist, "id"));
    System.out.printf(">> loaded  artist.name = %s\n", util.isLoaded(artist, "name"));
    System.out.printf(">> loaded  artist.events = %s\n", util.isLoaded(artist, "events"));
    assertTrue(util.isLoaded(artist, "id"));
    assertTrue(util.isLoaded(artist, "name"));
    assertFalse(util.isLoaded(artist, "events"));
}
 

import javax.persistence.EntityGraph; //导入依赖的package包/类
@Test
@InSequence(3)
public void shouldLoadArtistWithConcerts() throws Exception{
    PersistenceUnitUtil util =
        em.getEntityManagerFactory().getPersistenceUnitUtil();
    EntityGraph artistGraph = em.getEntityGraph("Artist.WithConcerts");
    Artist artist = (Artist)
        em.createQuery("Select a from Artist a")
        .setHint("javax.persistence.fetchgraph", artistGraph)
        .getResultList()
        .get(0);
    System.out.printf("++++ artist=%s\n", artist);
    System.out.printf("artist=%s\n", artist);
    assertTrue(util.isLoaded(artist, "id"));
    assertTrue(util.isLoaded(artist, "name"));
    assertTrue(util.isLoaded(artist, "events"));
}
 

import javax.persistence.EntityGraph; //导入依赖的package包/类
@Test
@InSequence(4)
public void shouldLoadArtistWithLiveConcertsAndNoContracts()
    throws Exception {
    PersistenceUnitUtil util =
            em.getEntityManagerFactory().getPersistenceUnitUtil();
    em.clear();
    EntityGraph artistGraph = em.getEntityGraph(
        "Artist.WithConcertsAndNoContracts");
    Artist artist = (Artist)
        em.createQuery("Select a from Artist a")
        .setHint("javax.persistence.fetchgraph", artistGraph)
        .getResultList()
        .get(0);
    System.out.printf("++++ artist=%s\n", artist);
    assertTrue(util.isLoaded(artist, "id"));
    assertTrue(util.isLoaded(artist, "name"));
    assertTrue(util.isLoaded(artist, "events"));
    ConcertEvent event = artist.getEvents().values().iterator().next();
    System.out.printf("++++ concert event=%s\n", event );
    assertTrue(util.isLoaded(event, "id"));
    assertTrue(util.isLoaded(event, "name"));
    assertTrue(util.isLoaded(event, "eventType"));
    assertFalse(util.isLoaded(event, "contracts"));
}
 

import javax.persistence.EntityGraph; //导入依赖的package包/类
@Test
@InSequence(5)
public void shouldLoadArtistWithLiveConcertsAndContracts()
    throws Exception{
    PersistenceUnitUtil util =
            em.getEntityManagerFactory().getPersistenceUnitUtil();
    em.clear();
    EntityGraph artistGraph = em.getEntityGraph("Artist.WithConcertsAndContracts");
    Artist artist = (Artist)
        em.createQuery("Select a from Artist a")
        .setHint("javax.persistence.fetchgraph", artistGraph)
        .getResultList()
        .get(0);
    System.out.printf("++++ artist=%s\n", artist);
    assertTrue(util.isLoaded(artist, "id"));
    assertTrue(util.isLoaded(artist, "name"));
    assertTrue(util.isLoaded(artist, "events"));
    ConcertEvent event = artist.getEvents().values().iterator().next();
    System.out.printf("++++ concert event=%s\n", event );
    assertTrue(util.isLoaded(event, "id"));
    assertTrue(util.isLoaded(event, "name"));
    assertTrue(util.isLoaded(event, "eventType"));
    assertTrue(util.isLoaded(event, "contracts"));
}