Java tutorial
/* * Copyright 2008-2014 the original author or authors. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package org.springframework.data.jpa.repository.support; import static org.springframework.data.jpa.repository.query.QueryUtils.COUNT_QUERY_STRING; import static org.springframework.data.jpa.repository.query.QueryUtils.DELETE_ALL_QUERY_STRING; import static org.springframework.data.jpa.repository.query.QueryUtils.applyAndBind; import static org.springframework.data.jpa.repository.query.QueryUtils.getQueryString; import static org.springframework.data.jpa.repository.query.QueryUtils.toOrders; import java.beans.PropertyDescriptor; import java.io.Serializable; import java.lang.reflect.InvocationTargetException; import java.util.ArrayList; import java.util.Collections; import java.util.List; import java.util.Map; import java.util.Map.Entry; import javax.persistence.EntityManager; import javax.persistence.LockModeType; import javax.persistence.NoResultException; import javax.persistence.Parameter; import javax.persistence.TypedQuery; import javax.persistence.criteria.CriteriaBuilder; import javax.persistence.criteria.CriteriaQuery; import javax.persistence.criteria.ParameterExpression; import javax.persistence.criteria.Path; import javax.persistence.criteria.Predicate; import javax.persistence.criteria.Root; import org.apache.commons.beanutils.BeanUtils; import org.springframework.dao.EmptyResultDataAccessException; import org.springframework.data.domain.Page; import org.springframework.data.domain.PageImpl; import org.springframework.data.domain.Pageable; import org.springframework.data.domain.Sort; import org.springframework.data.jpa.domain.Specification; import org.springframework.data.jpa.repository.JpaRepository; import org.springframework.data.jpa.repository.JpaSpecificationExecutor; import org.springframework.data.jpa.repository.query.QueryUtils; import org.springframework.stereotype.Repository; import org.springframework.transaction.annotation.Transactional; import org.springframework.util.Assert; /** * Default implementation of the {@link org.springframework.data.repository.CrudRepository} interface. This will offer * you a more sophisticated interface than the plain {@link EntityManager} . * * @author Oliver Gierke * @author Eberhard Wolff * @author Thomas Darimont * @param <T> the type of the entity to handle * @param <ID> the type of the entity's identifier */ @Repository @Transactional(readOnly = true) public class SimpleJpaRepository<T, ID extends Serializable> implements JpaRepository<T, ID>, JpaSpecificationExecutor<T> { private final JpaEntityInformation<T, ?> entityInformation; protected final EntityManager em; private final PersistenceProvider provider; private CrudMethodMetadata crudMethodMetadata; /** * Creates a new {@link SimpleJpaRepository} to manage objects of the given {@link JpaEntityInformation}. * * @param entityInformation must not be {@literal null}. * @param entityManager must not be {@literal null}. */ public SimpleJpaRepository(JpaEntityInformation<T, ?> entityInformation, EntityManager entityManager) { Assert.notNull(entityInformation); Assert.notNull(entityManager); this.entityInformation = entityInformation; this.em = entityManager; this.provider = PersistenceProvider.fromEntityManager(entityManager); } /** * Creates a new {@link SimpleJpaRepository} to manage objects of the given domain type. * * @param domainClass must not be {@literal null}. * @param em must not be {@literal null}. */ public SimpleJpaRepository(Class<T> domainClass, EntityManager em) { this(JpaEntityInformationSupport.getMetadata(domainClass, em), em); } /** * Configures a custom {@link CrudMethodMetadata} to be used to detect {@link LockModeType}s and query hints to be * applied to queries. * * @param crudMethodMetadata */ public void setRepositoryMethodMetadata(CrudMethodMetadata crudMethodMetadata) { this.crudMethodMetadata = crudMethodMetadata; } protected Class<T> getDomainClass() { return entityInformation.getJavaType(); } private String getDeleteAllQueryString() { return getQueryString(DELETE_ALL_QUERY_STRING, entityInformation.getEntityName()); } private String getCountQueryString() { String countQuery = String.format(COUNT_QUERY_STRING, provider.getCountQueryPlaceholder(), "%s"); return getQueryString(countQuery, entityInformation.getEntityName()); } /* * (non-Javadoc) * @see org.springframework.data.repository.CrudRepository#delete(java.io.Serializable) */ @Transactional public void delete(ID id) { Assert.notNull(id, "The given id must not be null!"); T entity = findOne(id); if (entity == null) { throw new EmptyResultDataAccessException( String.format("No %s entity with id %s exists!", entityInformation.getJavaType(), id), 1); } delete(entity); } /* * (non-Javadoc) * @see org.springframework.data.repository.CrudRepository#delete(java.lang.Object) */ @Transactional public void delete(T entity) { Assert.notNull(entity, "The entity must not be null!"); em.remove(em.contains(entity) ? entity : em.merge(entity)); } /* * (non-Javadoc) * @see org.springframework.data.repository.CrudRepository#delete(java.lang.Iterable) */ @Transactional public void delete(Iterable<? extends T> entities) { Assert.notNull(entities, "The given Iterable of entities not be null!"); for (T entity : entities) { delete(entity); } } /* * (non-Javadoc) * @see org.springframework.data.jpa.repository.JpaRepository#deleteInBatch(java.lang.Iterable) */ @Transactional public void deleteInBatch(Iterable<T> entities) { Assert.notNull(entities, "The given Iterable of entities not be null!"); if (!entities.iterator().hasNext()) { return; } applyAndBind(getQueryString(DELETE_ALL_QUERY_STRING, entityInformation.getEntityName()), entities, em) .executeUpdate(); } /* * (non-Javadoc) * @see org.springframework.data.repository.Repository#deleteAll() */ @Transactional public void deleteAll() { for (T element : findAll()) { delete(element); } } /* * (non-Javadoc) * @see org.springframework.data.jpa.repository.JpaRepository#deleteAllInBatch() */ @Transactional public void deleteAllInBatch() { em.createQuery(getDeleteAllQueryString()).executeUpdate(); } /* * (non-Javadoc) * @see org.springframework.data.repository.CrudRepository#findOne(java.io.Serializable) */ public T findOne(ID id) { Assert.notNull(id, "The given id must not be null!"); Class<T> domainType = getDomainClass(); if (crudMethodMetadata == null) { return em.find(domainType, id); } LockModeType type = crudMethodMetadata.getLockModeType(); Map<String, Object> hints = crudMethodMetadata.getQueryHints(); return type == null ? em.find(domainType, id, hints) : em.find(domainType, id, type, hints); } /* * (non-Javadoc) * @see org.springframework.data.jpa.repository.JpaRepository#getOne(java.io.Serializable) */ @Override public T getOne(ID id) { Assert.notNull(id, "The given id must not be null!"); return em.getReference(getDomainClass(), id); } /* * (non-Javadoc) * @see org.springframework.data.repository.CrudRepository#exists(java.io.Serializable) */ public boolean exists(ID id) { Assert.notNull(id, "The given id must not be null!"); if (entityInformation.getIdAttribute() == null) { return findOne(id) != null; } String placeholder = provider.getCountQueryPlaceholder(); String entityName = entityInformation.getEntityName(); Iterable<String> idAttributeNames = entityInformation.getIdAttributeNames(); String existsQuery = QueryUtils.getExistsQueryString(entityName, placeholder, idAttributeNames); TypedQuery<Long> query = em.createQuery(existsQuery, Long.class); if (!entityInformation.hasCompositeId()) { query.setParameter(idAttributeNames.iterator().next(), id); return query.getSingleResult() == 1L; } for (String idAttributeName : idAttributeNames) { Object idAttributeValue = entityInformation.getCompositeIdAttributeValue(id, idAttributeName); boolean complexIdParameterValueDiscovered = idAttributeValue != null && !query .getParameter(idAttributeName).getParameterType().isAssignableFrom(idAttributeValue.getClass()); if (complexIdParameterValueDiscovered) { // fall-back to findOne(id) which does the proper mapping for the parameter. return findOne(id) != null; } query.setParameter(idAttributeName, idAttributeValue); } return query.getSingleResult() == 1L; } /* * (non-Javadoc) * @see org.springframework.data.jpa.repository.JpaRepository#findAll() */ public List<T> findAll() { return getQuery(null, (Sort) null).getResultList(); } /* * (non-Javadoc) * @see org.springframework.data.repository.CrudRepository#findAll(ID[]) */ public List<T> findAll(Iterable<ID> ids) { if (ids == null || !ids.iterator().hasNext()) { return Collections.emptyList(); } ByIdsSpecification specification = new ByIdsSpecification(); TypedQuery<T> query = getQuery(specification, (Sort) null); return query.setParameter(specification.parameter, ids).getResultList(); } /* * (non-Javadoc) * @see org.springframework.data.jpa.repository.JpaRepository#findAll(org.springframework.data.domain.Sort) */ public List<T> findAll(Sort sort) { return getQuery(null, sort).getResultList(); } /* * (non-Javadoc) * @see org.springframework.data.repository.PagingAndSortingRepository#findAll(org.springframework.data.domain.Pageable) */ public Page<T> findAll(Pageable pageable) { if (null == pageable) { return new PageImpl<T>(findAll()); } return findAll(null, pageable); } /* * (non-Javadoc) * @see org.springframework.data.jpa.repository.JpaSpecificationExecutor#findOne(org.springframework.data.jpa.domain.Specification) */ public T findOne(Specification<T> spec) { try { return getQuery(spec, (Sort) null).getSingleResult(); } catch (NoResultException e) { return null; } } /* * (non-Javadoc) * @see org.springframework.data.jpa.repository.JpaSpecificationExecutor#findAll(org.springframework.data.jpa.domain.Specification) */ public List<T> findAll(Specification<T> spec) { return getQuery(spec, (Sort) null).getResultList(); } /* * (non-Javadoc) * @see org.springframework.data.jpa.repository.JpaSpecificationExecutor#findAll(org.springframework.data.jpa.domain.Specification, org.springframework.data.domain.Pageable) */ public Page<T> findAll(Specification<T> spec, Pageable pageable) { TypedQuery<T> query = getQuery(spec, pageable); return pageable == null ? new PageImpl<T>(query.getResultList()) : readPage(query, pageable, spec); } /* * (non-Javadoc) * @see org.springframework.data.jpa.repository.JpaSpecificationExecutor#findAll(org.springframework.data.jpa.domain.Specification, org.springframework.data.domain.Sort) */ public List<T> findAll(Specification<T> spec, Sort sort) { return getQuery(spec, sort).getResultList(); } /* * (non-Javadoc) * @see org.springframework.data.repository.CrudRepository#count() */ public long count() { return em.createQuery(getCountQueryString(), Long.class).getSingleResult(); } /* * (non-Javadoc) * @see org.springframework.data.jpa.repository.JpaSpecificationExecutor#count(org.springframework.data.jpa.domain.Specification) */ public long count(Specification<T> spec) { return getCountQuery(spec).getSingleResult(); } /* * (non-Javadoc) * @see org.springframework.data.repository.CrudRepository#save(java.lang.Object) */ @Transactional public <S extends T> S save(S entity) { if (entityInformation.isNew(entity)) { em.persist(entity); return entity; } else { T oldEntity = this.findOne((ID) (entityInformation.getId(entity))); if (oldEntity != null) { PropertyDescriptor[] pds = org.springframework.beans.BeanUtils .getPropertyDescriptors(getDomainClass()); List<String> ignore = new ArrayList<String>(); for (PropertyDescriptor pd : pds) { try { String v = BeanUtils.getProperty(entity, pd.getName()); if (v == null) ignore.add(pd.getName()); } catch (IllegalAccessException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (InvocationTargetException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (NoSuchMethodException e) { // TODO Auto-generated catch block e.printStackTrace(); } } org.springframework.beans.BeanUtils.copyProperties(entity, oldEntity, ignore.toArray(new String[] {})); entity = (S) oldEntity; } return em.merge(entity); } } /* * (non-Javadoc) * @see org.springframework.data.jpa.repository.JpaRepository#saveAndFlush(java.lang.Object) */ @Transactional public <S extends T> S saveAndFlush(S entity) { S result = save(entity); flush(); return result; } /* * (non-Javadoc) * @see org.springframework.data.jpa.repository.JpaRepository#save(java.lang.Iterable) */ @Transactional public <S extends T> List<S> save(Iterable<S> entities) { List<S> result = new ArrayList<S>(); if (entities == null) { return result; } for (S entity : entities) { result.add(save(entity)); } return result; } /* * (non-Javadoc) * @see org.springframework.data.jpa.repository.JpaRepository#flush() */ @Transactional public void flush() { em.flush(); } /** * Reads the given {@link TypedQuery} into a {@link Page} applying the given {@link Pageable} and * {@link Specification}. * * @param query must not be {@literal null}. * @param spec can be {@literal null}. * @param pageable can be {@literal null}. * @return */ protected Page<T> readPage(TypedQuery<T> query, Pageable pageable, Specification<T> spec) { query.setFirstResult(pageable.getOffset()); query.setMaxResults(pageable.getPageSize()); Long total = QueryUtils.executeCountQuery(getCountQuery(spec)); List<T> content = total > pageable.getOffset() ? query.getResultList() : Collections.<T>emptyList(); return new PageImpl<T>(content, pageable, total); } /** * Creates a new {@link TypedQuery} from the given {@link Specification}. * * @param spec can be {@literal null}. * @param pageable can be {@literal null}. * @return */ protected TypedQuery<T> getQuery(Specification<T> spec, Pageable pageable) { Sort sort = pageable == null ? null : pageable.getSort(); return getQuery(spec, sort); } /** * Creates a {@link TypedQuery} for the given {@link Specification} and {@link Sort}. * * @param spec can be {@literal null}. * @param sort can be {@literal null}. * @return */ protected TypedQuery<T> getQuery(Specification<T> spec, Sort sort) { CriteriaBuilder builder = em.getCriteriaBuilder(); CriteriaQuery<T> query = builder.createQuery(getDomainClass()); Root<T> root = applySpecificationToCriteria(spec, query); query.select(root); if (sort != null) { query.orderBy(toOrders(sort, root, builder)); } return applyRepositoryMethodMetadata(em.createQuery(query)); } /** * Creates a new count query for the given {@link Specification}. * * @param spec can be {@literal null}. * @return */ protected TypedQuery<Long> getCountQuery(Specification<T> spec) { CriteriaBuilder builder = em.getCriteriaBuilder(); CriteriaQuery<Long> query = builder.createQuery(Long.class); Root<T> root = applySpecificationToCriteria(spec, query); if (query.isDistinct()) { query.select(builder.countDistinct(root)); } else { query.select(builder.count(root)); } return em.createQuery(query); } /** * Applies the given {@link Specification} to the given {@link CriteriaQuery}. * * @param spec can be {@literal null}. * @param query must not be {@literal null}. * @return */ private <S> Root<T> applySpecificationToCriteria(Specification<T> spec, CriteriaQuery<S> query) { Assert.notNull(query); Root<T> root = query.from(getDomainClass()); if (spec == null) { return root; } CriteriaBuilder builder = em.getCriteriaBuilder(); Predicate predicate = spec.toPredicate(root, query, builder); if (predicate != null) { query.where(predicate); } return root; } private TypedQuery<T> applyRepositoryMethodMetadata(TypedQuery<T> query) { if (crudMethodMetadata == null) { return query; } LockModeType type = crudMethodMetadata.getLockModeType(); TypedQuery<T> toReturn = type == null ? query : query.setLockMode(type); for (Entry<String, Object> hint : crudMethodMetadata.getQueryHints().entrySet()) { query.setHint(hint.getKey(), hint.getValue()); } return toReturn; } /** * Specification that gives access to the {@link Parameter} instance used to bind the ids for * {@link SimpleJpaRepository#findAll(Iterable)}. Workaround for OpenJPA not binding collections to in-clauses * correctly when using by-name binding. * * @see https://issues.apache.org/jira/browse/OPENJPA-2018?focusedCommentId=13924055 * @author Oliver Gierke */ @SuppressWarnings("rawtypes") private final class ByIdsSpecification implements Specification<T> { ParameterExpression<Iterable> parameter; /* * (non-Javadoc) * @see org.springframework.data.jpa.domain.Specification#toPredicate(javax.persistence.criteria.Root, javax.persistence.criteria.CriteriaQuery, javax.persistence.criteria.CriteriaBuilder) */ public Predicate toPredicate(Root<T> root, CriteriaQuery<?> query, CriteriaBuilder cb) { Path<?> path = root.get(entityInformation.getIdAttribute()); parameter = cb.parameter(Iterable.class); return path.in(parameter); } } }