Java Selection类代码示例

import javax.persistence.criteria.Selection; //导入依赖的package包/类
/**
 * {@inheritDoc}
 */
@Override
public <T extends BaseEntity, C> List<C> findByCriteriaAndMapConstructor(ConstructorCriteria<T, C> criteria) {
    EntityManager em = this.emf.createEntityManager();
    try {
        CriteriaBuilder cb = em.getCriteriaBuilder();
        CriteriaQuery<C> cq = cb.createQuery(criteria.getConstructorClass());
        Root<T> root = cq.from(criteria.getEntity());
        return em.createQuery(cq.select(cb.construct(criteria.getConstructorClass(), criteria.getSelections()
                .stream()
                .map(root::get)
                .collect(Collectors.toList())
                .toArray(new Selection[LEN_ZERO])))
                .where(JpaUtil.getPredicates(criteria.getCriteriaAttributes(), cb, root)))
                .getResultList();
    } catch (RuntimeException ex) {
        LOGGER.error(ex.getMessage(), ex);
        throw new PersistenceException(ex.getMessage(), ex);
    } finally {
        JpaUtil.closeEntityManager(em);
    }
}
 

import javax.persistence.criteria.Selection; //导入依赖的package包/类
private <S> S aggregate(CriteriaBuilder builder, CriteriaQuery<S> query, Root<E> root, Specification<E> spec, List<Selection<?>> selectionList, LockModeType lockMode) {
	if (selectionList != null) {
		Predicate predicate = spec.toPredicate(root, query, builder);
		if (predicate != null) {
			query.where(predicate);
		}
		query.multiselect(selectionList);
		return (S) em.createQuery(query).setLockMode(lockMode).getSingleResult();
	}
	return null;
}
 

import javax.persistence.criteria.Selection; //导入依赖的package包/类
@Override
public T select(Object... selections) {
	if (!beforeMethodInvoke()) {
		return (T) this;
	}
	List<Selection<?>> list = new ArrayList<Selection<?>>(selections.length);
	for (Object selection : selections) {
		if (selection instanceof String) {
			parseSelectionStr(list, (String) selection);
		} else if (selection instanceof Selection) {
			list.add((Selection<?>) selection);
		}
	}
	select(list.toArray(new Selection<?>[list.size()]));
	return (T) this;
}
 

import javax.persistence.criteria.Selection; //导入依赖的package包/类
private void parseSelectionStr(List<Selection<?>> result, String selection) {
	String[] ps = selection.split("\\s*,\\s*");
	for (String p : ps) {
		String alias = p.trim();
		String[] pa = alias.split("\\s+[aA][sS]\\s+");
		if (pa.length > 1) {
			alias = pa[1];
		} else {
			pa = alias.split("\\s+");
			if (pa.length > 1) {
				alias = pa[1];
			}
		}
		result.add(root.get(ps[0]).alias(alias));
	}
}
 

import javax.persistence.criteria.Selection; //导入依赖的package包/类
/**
 * @param distinctFields
 * @return
 * @throws IllegalArgumentException if the field is not part of the entity
 */
public JpaELFilterImpl distinct(String... distinctFields) {
	if (distinctFields != null) {
		List<Selection> multiSelection = new ArrayList<>();
		for (String f : distinctFields) {
			multiSelection.add(resultRoot.get(f));
		}

		if (distinctFields.length == 1) {
			critQ.select(multiSelection.get(0)).distinct(true);
		} else if (distinctFields.length > 0) {
			critQ.multiselect(multiSelection).distinct(true);
		}
	}

	return this;
}
 

import javax.persistence.criteria.Selection; //导入依赖的package包/类
@Override
public <S> S sum(Class<S> resultClass, Specification<E> spec, LockModeType lockMode, List<String> properties) {
	CriteriaBuilder builder = em.getCriteriaBuilder();
	CriteriaQuery<S> query = builder.createQuery(resultClass);
	Root<E> root = query.from(getDomainClass());
	List<Selection<?>> selectionList = Lists.newArrayList();
	for (String property : properties) {
		selectionList.add(builder.sum(getAttributeName(root, property)));
	}
	return aggregate(builder, query, root, spec, selectionList, lockMode);
}
 

import javax.persistence.criteria.Selection; //导入依赖的package包/类
@Override
public void addSelection(Expression<?> expression, String name) {
	Selection<?> selection = criteriaQuery.getSelection();

	List<Selection<?>> newSelection = new ArrayList<>();
	if (selection != null) {
		if (selection.isCompoundSelection()) {
			newSelection.addAll(selection.getCompoundSelectionItems());
		}
		else {
			newSelection.add(selection);
		}
	}
	newSelection.add(expression);
	criteriaQuery.multiselect(newSelection);
}
 

import javax.persistence.criteria.Selection; //导入依赖的package包/类
/**
 * {@inheritDoc}
 */
@Override
public <T extends BaseEntity> List<Tuple> findByTupleQuery(TupleQueryCriteria<T> criteria) {
    EntityManager em = this.emf.createEntityManager();
    try {
        CriteriaBuilder cb = em.getCriteriaBuilder();
        CriteriaQuery<Tuple> cq = cb.createTupleQuery();
        Root<T> root = cq.from(criteria.getEntity());
        return em.createQuery(cq.multiselect(criteria.getSelections()
                .stream()
                .map(root::get)
                .collect(Collectors.toList())
                .toArray(new Selection[LEN_ZERO]))
                .where(cb.and(JpaUtil.getPredicates(criteria.getCriteriaAttributes(), cb, root))))
                .getResultList();
    } catch (RuntimeException ex) {
        LOGGER.error(ex.getMessage(), ex);
        throw new PersistenceException(ex.getMessage(), ex);
    } finally {
        JpaUtil.closeEntityManager(em);
    }
}
 

import javax.persistence.criteria.Selection; //导入依赖的package包/类
/**
 * {@inheritDoc}
 */
public boolean visit(JpqlSubselect node, CriteriaHolder query) {
    try {
        Subquery<Object> subquery = query.createSubquery();
        node.jjtGetChild(1).visit(this, query);
        node.jjtGetChild(0).visit(this, query);
        List<Selection<?>> selections = query.<List<Selection<?>>>getCurrentValue();
        subquery.select((Expression<Object>)selections.iterator().next());
        query.setValue(subquery);
        for (int i = 2; i < node.jjtGetNumChildren(); i++) {
            node.jjtGetChild(i).visit(this, query);
        }
        query.setValue(subquery);
        return false;
    } finally {
        query.removeSubquery();
    }
}
 

import javax.persistence.criteria.Selection; //导入依赖的package包/类
@Test
public void criteria() {
    CriteriaBuilder cb = entityManager.getCriteriaBuilder();
    CriteriaQuery<ClientEntityBrowserDto> c = cb.createQuery(ClientEntityBrowserDto.class);
    Root<Client> client = c.from(Client.class);

    Join<Client, ClientGroup> clientGroup = client.join("group", JoinType.LEFT);
    Join<Client, ClientStructure> clientStructure = client.join("structure", JoinType.LEFT);
    Join<ClientType, ClientTypeGroup> clientTypeGroup
        = client.join("type", JoinType.LEFT).join("clientTypeGroup", JoinType.LEFT);

    Selection<ClientEntityBrowserDto> selection
        = cb.construct(ClientEntityBrowserDto.class,
                       client.<Integer>get("id"),
                       client.<String>get("number"),
                       client.<String>get("name"),
                       clientTypeGroup.<String>get("name"),
                       clientGroup.<String>get("name"),
                       clientStructure.<String>get("name"));

    c.select(selection);
    c.distinct(true);
    TypedQuery<ClientEntityBrowserDto> query = entityManager.createQuery(c);
    assertTrue(query.getResultList().isEmpty());
}
 

import javax.persistence.criteria.Selection; //导入依赖的package包/类
/**
	 * Package-protected method to centralize checking of criteria query multi-selects as defined by the
	 * {@link CriteriaQuery#multiselect(List)}  method.
	 *
	 * @param selections The selection varargs to check
	 *
	 * @throws IllegalArgumentException If the selection items are not valid per {@link CriteriaQuery#multiselect}
	 * documentation.
	 * <i>&quot;An argument to the multiselect method must not be a tuple-
     * or array-valued compound selection item.&quot;</i>
	 */
	void checkMultiselect(List<Selection<?>> selections) {
//		final HashSet<String> aliases = new HashSet<String>( CollectionHelper.determineProperSizing( selections.size() ) );
//
//		for ( Selection<?> selection : selections ) {
//			if ( selection.isCompoundSelection() ) {
//				if ( selection.getJavaType().isArray() ) {
//					throw new IllegalArgumentException(
//							"Selection items in a multi-select cannot contain compound array-valued elements"
//					);
//				}
//				if ( Tuple.class.isAssignableFrom( selection.getJavaType() ) ) {
//					throw new IllegalArgumentException(
//							"Selection items in a multi-select cannot contain compound tuple-valued elements"
//					);
//				}
//			}
//			if ( StringHelper.isNotEmpty( selection.getAlias() ) ) {
//				boolean added = aliases.add( selection.getAlias() );
//				if ( ! added ) {
//					throw new IllegalArgumentException( "Multi-select expressions defined duplicate alias : " + selection.getAlias() );
//				}
//			}
//		}
	}
 

import javax.persistence.criteria.Selection; //导入依赖的package包/类
private List<JpaExpression<?>> toExpressions(List<Selection<?>> selections) {
	if ( selections == null || selections.isEmpty() ) {
		return Collections.emptyList();
	}

	final ArrayList<JpaExpression<?>> expressions = new ArrayList<>();
	for ( Selection<?> selection : selections ) {
		if ( selection instanceof JpaExpression ) {
			expressions.add( (JpaExpression) selection );
		}
		else {
			throw new CriteriaBuilderException(
					"Expecting javax.persistence.criteria.Selection to be " +
							"JpaExpression, but found " +
							selection.toString()
			);
		}
	}

	return expressions;
}
 

import javax.persistence.criteria.Selection; //导入依赖的package包/类
public <E> List<Selection<?>> prepareProjectingQuery(MetaJpaConstructor<E,?,?> projection, From<?,? extends E> selection) {
    logger.debug("prepareProjectingQuery({},{})", projection, selection);
    
    List<Selection<?>> ret;
    if (projection instanceof IdProjection) {
        logger.debug("IdProjection. Replacing selection {} with just Id.", selection);
        ret = Collections.<Selection<?>>newList(selection.get(QueryUtils.<E,Object>id(selection.getJavaType(), em.apply())));
    } else {
        ret = newListOfSize(projection.getParameters().size());
        for (Tuple3<Integer, Attribute<?,?>, Class<?>> t: zip(range(0), projection.getParameters(), projection.getConstructorParameterTypes())) {
            int index = t._1;
            Attribute<?,?> param = t._2;
            Class<?> constuctorParameterType = t._3;
            ret.add(transformSelectionForQuery(param, isId(constuctorParameterType) || isWrapperOfIds(projection, index), selection, projection));
        }
    }
    
    logger.debug("prepareProjectingQuery -> {}", ret);
    return ret;
}
 

import javax.persistence.criteria.Selection; //导入依赖的package包/类
/**
 * Create a TypedQuery from a request page
 * @param page request page
 * @return new TypedQuery
 */
@SuppressWarnings("unchecked")
private <K> TypedQuery<K> getCriteriaQuery(Page<K> page) {
	CriteriaQuery<K> criteria = getCriteria(page);
	
	CriteriaQuery<Long> countCriteria = (CriteriaQuery<Long>) getCriteria(page);
	CriteriaBuilder cb = em.getCriteriaBuilder();
	
	Root<?> root = countCriteria.getRoots().iterator().next();
	countCriteria.select(cb.count(root));
	
	page.setCount((em.createQuery(countCriteria).getSingleResult())
			.intValue());
	
	
	criteria.orderBy(getOrder(page, criteria));
	
	// Add default select to entity class if none was set.
	if (criteria.getSelection() == null) {
		criteria.select((Selection<? extends K>) root);
	}
	
	return em.createQuery(criteria);
}
 

import javax.persistence.criteria.Selection; //导入依赖的package包/类
@Override
public <S> S sum(Class<S> resultClass, Specification<E> spec, LockModeType lockMode, List<SingularAttribute<E, ? extends Number>> properties) {
	CriteriaBuilder builder = em.getCriteriaBuilder();
	CriteriaQuery<S> query = builder.createQuery(resultClass);
	Root<E> root = query.from(getDomainClass());
	List<Selection<?>> selectionList = Lists.newArrayList();
	for (SingularAttribute<E, ? extends Number> property : properties) {
		selectionList.add(builder.sum(root.get(property)));
	}
	return aggregate(builder, query, root, spec, selectionList, lockMode);
}