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A library of classes shared across the Eureka! Clinical platform.
package org.eurekaclinical.standardapis.dao;
/*-
* #%L
* Eureka! Clinical Standard APIs
* %%
* Copyright (C) 2016 Emory University
* %%
* 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.
* #L%
*/
import java.util.List;
import javax.persistence.EntityManager;
import javax.persistence.criteria.CriteriaBuilder;
import javax.persistence.criteria.CriteriaQuery;
import javax.persistence.criteria.Root;
import javax.persistence.metamodel.SingularAttribute;
import javax.inject.Provider;
import javax.persistence.NoResultException;
/**
* Generic implementation of the {@link Dao} interface. It is a wrapper around
* the {@link EntityManager} interface.
*
* @param The type of the entity.
* @param The type of the unique identifier for the entity.
* @author hrathod
*/
public class GenericDao implements Dao {
/**
* The type for the entities this DAO instance handles.
*/
final Class entityClass;
/**
* Provides entity managers on demand.
*/
private final Provider managerProvider;
private final DatabaseSupport databaseSupport;
/**
* Creates a generic DAO that handles the given type of entity. The entity
* manager provider is used to fetch entity managers to interact with the
* data store.
*
* @param inEntityClass The type of entities to handle.
* @param inManagerProvider Provides entity managers on demand.
*/
protected GenericDao(Class inEntityClass,
Provider inManagerProvider) {
this.entityClass = inEntityClass;
this.managerProvider = inManagerProvider;
this.databaseSupport = new DatabaseSupport(this.managerProvider);
}
/**
* Creates an entity in the database. It calls
* {@link EntityManager#persist(java.lang.Object) } and throws the same
* exceptions.
*
* @param entity the entity to create.
*
* @return the created entity with any primary key field populated.
*
*/
@Override
public final T create(T entity) {
EntityManager entityManager = this.getEntityManager();
entityManager.persist(entity);
return entity;
}
/**
* Selects an entity from the database. It calls
* {@link EntityManager#find(java.lang.Class, java.lang.Object) } and throws
* the same exceptions.
*
* @param uniqueId the primary key of the entity to select.
*
* @return the entity, or null if none has the specified
* primary key.
*/
@Override
public final T retrieve(PK uniqueId) {
return this.getEntityManager().find(this.entityClass, uniqueId);
}
/**
* Updates an entity in the database. It calls
* {@link EntityManager#merge(java.lang.Object) } and throws the same
* exceptions.
*
* @param entity the updates to the entity.
*
* @return the updated entity.
*/
@Override
public final T update(T entity) {
EntityManager entityManager = this.getEntityManager();
T result = entityManager.merge(entity);
return result;
}
/**
* Deletes an entity from the database. It calls
* {@link EntityManager#remove(java.lang.Object) } and throws the same
* exceptions.
*
* @param entity the entity to delete.
*
* @return the deleted entity.
*/
@Override
public final T remove(T entity) {
EntityManager entityManager = this.getEntityManager();
if (entityManager.contains(entity)) {
entityManager.remove(entity);
} else {
entityManager.remove(entityManager.merge(entity));
}
return entity;
}
/**
* Synchronizes the given entity with what is currently in the database.
*
* @param entity the entity to refresh.
*
* @return the refreshed entity.
*/
@Override
public final T refresh(T entity) {
this.getEntityManager().refresh(entity);
return entity;
}
/**
* Gets all of this DAO's entities.
*
* @return a list of entities. Guaranteed not null.
*/
@Override
public final List getAll() {
return this.databaseSupport.getAll(this.entityClass);
}
/**
* Gets all of this DAO's entities ordered by the provided attribute in
* ascending order.
*
* @param attribute the attribute to order by.
*
* @return an ordered list of entities. Guaranteed not null.
*/
protected final List getListAsc(SingularAttribute attribute) {
EntityManager entityManager = this.getEntityManager();
CriteriaBuilder builder = entityManager.getCriteriaBuilder();
CriteriaQuery criteriaQuery = builder.createQuery(this.entityClass);
Root root = criteriaQuery.from(this.entityClass);
criteriaQuery.orderBy(builder.asc(root.get(attribute)));
return entityManager.createQuery(criteriaQuery).getResultList();
}
/**
* Gets the entity that has the target value of the specified attribute.
*
* @param the type of the attribute and target value.
* @param attribute the attribute of the entity to compare.
* @param value the target value of the given attribute.
*
* @return the matching entity, or null if there is none.
*/
protected final T getUniqueByAttribute(SingularAttribute attribute,
Y value) {
try {
return this.databaseSupport.getUniqueByAttribute(this.entityClass, attribute, value);
} catch (NoResultException ex) {
return null;
}
}
/**
* Gets the entity that has the target value of the specified attribute.
*
* @param the type of the attribute and target value.
* @param attributeName the name of the attribute.
* @param value the target value of the given attribute.
*
* @return the matching entity, or null if there is none.
*/
protected final T getUniqueByAttribute(String attributeName, Y value) {
try {
return this.databaseSupport.getUniqueByAttribute(this.entityClass, attributeName, value);
} catch (NoResultException ex) {
return null;
}
}
/**
* Gets the entities that have the target value of the specified attribute.
*
* @param the type of the attribute and target value.
* @param attribute the attribute of the entity to compare.
* @param value the target value of the given attribute.
*
* @return the matching entities. Guaranteed not null.
*/
protected final List getListByAttribute(SingularAttribute attribute, Y value) {
return this.databaseSupport.getListByAttribute(this.entityClass, attribute, value);
}
/**
* Executes a query for all entities whose path value is the same as the
* given target value. The path is provided by the {@link QueryPathProvider}
* and is followed through to get the resulting value. That resulting value
* is compared to the given target value in the query.
*
* @param provider provides the path from the entity to the target
* attribute/column.
* @param value the target value to compare with the resulting attribute
* value.
* @param the type of the target value and resulting attribute/column
* value.
*
* @return a list of entities that match the given criteria.
*/
protected final List getListByAttribute(QueryPathProvider provider, Y value) {
return this.databaseSupport.getListByAttribute(this.entityClass, provider, value);
}
/**
* Gets the entities that have any of the target values of the specified
* attribute.
*
* @param the type of the attribute and target value.
* @param attribute the attribute of the entity to compare.
* @param values the target values of the given attribute.
*
* @return the matching entities. Guaranteed not null.
*/
protected final List getListByAttributeIn(SingularAttribute attribute, List values) {
return this.databaseSupport.getListByAttributeIn(this.entityClass, attribute, values);
}
/**
* Executes a query for all entities whose path value is any of the target
* values. The path is provided by the {@link QueryPathProvider} and is
* followed through to get the resulting value. That resulting value is
* compared to the given target values in the query.
*
* @param the type of the target value and resulting attribute/column
* value.
* @param provider provides the path from the entity to the target
* attribute/column.
* @param values the target values of the given attribute.
*
* @return A list of entities that match the given criteria.
*/
protected final List getListByAttributeIn(QueryPathProvider provider, List values) {
return this.databaseSupport.getListByAttributeIn(this.entityClass, provider, values);
}
/**
* Returns an entity manager that can be used to interact with the data
* source.
*
* @return the entity manager.
*/
protected final EntityManager getEntityManager() {
return this.managerProvider.get();
}
protected final DatabaseSupport getDatabaseSupport() {
return this.databaseSupport;
}
}
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