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Hibernate extension for Data Access classes
/**
*
*/
package rs.data.hibernate.dao;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;
import org.hibernate.Criteria;
import org.hibernate.ScrollMode;
import org.hibernate.ScrollableResults;
import org.hibernate.Session;
import org.hibernate.criterion.Criterion;
import org.hibernate.criterion.Order;
import org.hibernate.criterion.Projections;
import org.hibernate.criterion.Restrictions;
import rs.data.api.bo.GeneralBO;
import rs.data.hibernate.HibernateDaoMaster;
import rs.data.impl.bo.AbstractBO;
import rs.data.impl.dao.AbstractDAO;
import rs.data.impl.dto.GeneralDTO;
import rs.data.util.DaoIterator;
/**
* Implements the Hibernate specific functions.
* @param type of Key
* @param type of Transfer Object
* @param type of Business Object Implementation
* @param type of Business Object Interface
* @author ralph
*
*/
public abstract class AbstractHibernateDAO, B extends AbstractBO, C extends GeneralBO> extends AbstractDAO {
/**
* Constructor.
* @param factory
*/
public AbstractHibernateDAO() {
super();
}
/******************************** FINDING ***************************/
/**
* {@inheritDoc}
*/
@SuppressWarnings("unchecked")
@Override
protected T _findById(K id) {
T rc = (T) getSession().get(getTransferClass(), id);
return rc;
}
/**
* Find objects by IDs.
* @param ids collection of IDs
* @return list of objects with specified IDd
*/
public List findById(Collection ids) {
if ((ids == null) || ids.isEmpty()) return new ArrayList();
return _findByCriteria(buildCriteria(Restrictions.in("id", ids)));
}
/**
* Returns the number of domain objects.
* @return number of objects.
*/
public int getObjectCount() {
return getRowCount(buildCriteria());
}
/**
* Returns the number of objects with default criteria matched.
* This method shall be used if you want to count only non-deleted objects.
* @return number of objects
*/
public int getDefaultObjectCount() {
return getRowCount(getDefaultCriteria());
}
/**
* {@inheritDoc}
*/
@Override
protected List _findAll(int firstResult, int maxResults) {
Criteria criteria = buildCriteria(firstResult, maxResults);
return _findByCriteria(criteria);
}
/**
* {@inheritDoc}
*/
@Override
protected List _findDefaultAll(int firstResult, int maxResults) {
Criteria criteria = getDefaultCriteria();
if (criteria == null) criteria = buildCriteria();
return _findByCriteria(filterResult(criteria, firstResult, maxResults));
}
/**
* {@inheritDoc}
*/
@Override
protected Iterator _iterateAll(int firstResult, int maxResults) {
return _iterateByCriteria(null, null, firstResult, maxResults);
}
/**
* {@inheritDoc}
*/
@Override
protected Iterator _iterateDefaultAll(int firstResult, int maxResults) {
Criterion criterions[] = getDefaultCriterions();
return _iterateByCriteria(criterions, null, firstResult, maxResults);
}
/******************************** CREATE ***************************/
/**
* {@inheritDoc}
*/
@Override
protected void _create(T object) {
// Just save
getSession().save(object);
}
/******************************** UPDATE ***************************/
/**
* {@inheritDoc}
*/
@Override
protected void _save(T object) {
Session session = getSession();
session.merge(object);
}
/******************************** DELETE ***************************/
/**
* {@inheritDoc}
*/
@SuppressWarnings("unchecked")
@Override
protected void _delete(T object) {
object = (T)getSession().merge(object);
getSession().delete(object);
}
/**
* Deletes all objects that match default criteria.
* @return number of object deleted
*/
@Override
protected int _deleteDefaultAll() {
return deleteByCriteria(getDefaultCriterions());
}
/**
* Deletes all objects.
* @return number of object deleted
*/
@Override
protected int _deleteAll() {
return deleteByCriteria(null);
}
/************************************ Criteria stuff ******************************************/
/**
* Returns the Hibernate session. This method will start a new transaction
* if required.
*
* @return hibernate session.
*/
public Session getSession() {
return ((HibernateDaoMaster)getDaoMaster()).getSession();
}
/**
* Returns a default Hibernate criteria for search.
* This can be used to simplify queries when tables may contain soft-deleted objects.
* This abstract implementation return null.
* @return a default criteria to be used
*/
protected Criteria getDefaultCriteria() {
return buildCriteria(getDefaultCriterions());
}
/**
* Returns the default criterions.
* @return
*/
protected Criterion[] getDefaultCriterions() {
return null;
}
/**
* Finds a single object defined by the Hibernate criteria.
* Note that the criteria might match many objects. Only the first result will
* be returned.
* @param criteria criteria for search
* @return first object matching the criteria
*/
protected T _findSingleByCriteria(Criteria criteria) {
criteria.setMaxResults(1);
List l = _findByCriteria(criteria);
if (l.size() > 0) return l.get(0);
return null;
}
/**
* Finds a single object defined by the Hibernate criteria.
* Note that the criteria might match many objects. Only the first result will
* be returned.
* @param criteria criteria for search
* @return first object matching the criteria
*/
protected C findSingleByCriteria(Criteria criteria) {
T rc = _findSingleByCriteria(criteria);
return getBusinessObject(rc);
}
/**
* Builds an Hibernate criteria with unlimited result count.
* @param criterion list of criterions to be added.
* @return the Hibernate criteria
*/
protected Criteria buildCriteria(Criterion... criterion) {
return buildCriteria(-1, -1, criterion);
}
/**
* Builds an Hibernate criteria with unlimited result count.
* @param firstResult index of first result returned
* @param maxResults maximum number of results returned
* @param criterion list of criterions to be added.
* @return the Hibernate criteria
*/
protected Criteria buildCriteria(int firstResult, int maxResults, Criterion... criterion) {
return buildCustomCriteria(getTransferClass(), firstResult, maxResults, criterion);
}
/**
* Builds an Hibernate criteria with unlimited result count.
* @param firstResult index of first result returned
* @param maxResults maximum number of results returned
* @param criterion list of criterions to be added.
* @return the Hibernate criteria
*/
protected Criteria buildCustomCriteria(Class forClass, int firstResult, int maxResults, Criterion... criterion) {
if (forClass == null) return null;
org.hibernate.Criteria crit = getSession().createCriteria(forClass);
if (criterion != null) {
for (Criterion c : criterion) {
crit.add(c);
}
}
return filterResult(crit, firstResult, maxResults);
}
/**
* Applies the result count limitation to the Hibernate criteria.
* @param crit criteria to be limited
* @param firstResult index of first result returned
* @param maxResults maximum number of results returned
* @return limited criteria.
*/
protected Criteria filterResult(Criteria crit, int firstResult, int maxResults) {
if (firstResult > 0) crit.setFirstResult(firstResult);
if (maxResults > 0) crit.setMaxResults(maxResults);
return crit;
}
/**
* Finds all DTOs matching the Hibernate criteria.
* @param crit Hibernate criteria
* @return the list of objects matching the criteria
*/
@SuppressWarnings("unchecked")
protected List _findByCriteria(Criteria crit) {
if (crit == null) crit = buildCriteria();
List rc = crit.list();
return rc;
}
/**
* Finds all BOs matching the Hibernate criteria.
* @param crit Hibernate criteria
* @return the list of objects matching the criteria
*/
protected List findByCriteria(Criteria crit) {
List l = _findByCriteria(crit);
List rc = new ArrayList();
wrap(rc, l);
return rc;
}
/**
* Execute an unspecific Hibernate criteria.
* If the criteria returns T then {@link AbstractHibernateDAO#findByCriteria(org.hibernate.Criteria, boolean)}
* must be used
* @param crit Hibernate criteria
* @return the list of objects matching the criteria
*/
protected List executeCriteria(Criteria crit) {
if (crit == null) crit = buildCriteria();
return crit.list();
}
/**
* Creates an iterator object for the Hibernate criteria.
* Use this inside subclasses as a convenience method.
* @param crit Hibernate criteria
* @return iterator object for the criteria
*/
protected DaoIterator _iterateByCriteria(Criterion criterions[]) {
return _iterateByCriteria(criterions, null, -1, -1);
}
/**
* Creates an iterator object for the Hibernate criteria.
* Use this inside subclasses as a convenience method.
* @param crit Hibernate criteria
* @return iterator object for the criteria
*/
protected DaoIterator _iterateByCriteria(Criterion criterions[], Order orders[]) {
return _iterateByCriteria(criterions, orders, -1, -1);
}
/**
* Creates an iterator object for the Hibernate criteria.
* Use this inside subclasses as a convenience method.
* @param criterions Hibernate criterions
* @param orders Hibernate orders
* @param firstResult index of first result to return
* @param maxResults maximum number of results to return
* @return iterator object for the criteria
*/
protected DaoIterator _iterateByCriteria(Criterion criterions[], Order orders[], int firstResult, int maxResults) {
return new IteratorImpl(criterions, orders, firstResult, maxResults);
}
/**
* Creates an iterator object for the Hibernate criteria.
* Use this inside subclasses as a convenience method.
* @param crit Hibernate criteria
* @return iterator object for the criteria
*/
protected DaoIterator iterateBy(Criterion criterions[], Order orders[], int firstResult, int maxResults) {
return wrap(_iterateByCriteria(criterions, orders, firstResult, maxResults));
}
/**
* Counts the number of objects returned by this Hibernate criteria.
* Use this inside subclasses as a convenience method.
* @param crit Hibernate criteria
* @return number of objects returned by the criteria
*/
protected int getRowCount(Criteria crit) {
crit = crit.setProjection(Projections.rowCount());
crit.setReadOnly(true);
List rc = crit.list();
long count = (Long)rc.get(0);
return (int)count;
}
/**
* Deletes all objects matching this criteria.
* @param criteria criteria for deletion
* @return number of objects deleted
*/
protected int deleteByCriteria(Criterion criterions[]) {
int rc = 0;
Iterator i = _iterateByCriteria(criterions, null);
while (i.hasNext()) {
_delete(i.next());
rc++;
}
return rc;
}
/**
* Returns the result count for this criteria. The Criteria object will be changed and cannot
* be used as a result-returning query anymore.
* @param criteria Criteria for object (row) count
* @return the row count.
*/
protected int getObjectCount(Criteria criteria) {
if (criteria == null) criteria = buildCriteria();
criteria.setProjection(Projections.rowCount());
return (Integer) criteria.list().get(0);
}
/**
* Iterator for DTOs.
* Funny thing: it can be reused at any time!
* @author ralph
*
*/
protected class IteratorImpl implements DaoIterator {
private ScrollableResults scrollableResult = null;
private T nextObject = null;
private Criteria criteria;
private Criterion criterions[];
private Order orders[];
private int firstResult;
private int maxResults;
/**
* Constructs the iterator.
* @param daoMaster DAO master
* @param crit Hibernate criteria
*/
public IteratorImpl(Criterion criterions[], Order orders[], int firstResult, int maxResults) {
this.criterions = criterions;
this.orders = orders;
this.firstResult = firstResult;
this.maxResults = maxResults;
}
/**
* Returns true when there is another object to be read.
* @return true or false.
*/
@Override
public boolean hasNext() {
if (nextObject == null) retrieveNext();
return nextObject != null;
}
/**
* Returns the next object.
* @return next object
*/
@Override
public T next() {
if (nextObject == null) retrieveNext();
T rc = nextObject;
nextObject = null;
return rc;
}
/**
* Retrieves the next object from the underlying Hibernate result.
*/
@SuppressWarnings("unchecked")
private void retrieveNext() {
if (nextObject != null) return;
// Create scrollable result
if (scrollableResult == null) {
// Create criteria now
if (criteria == null) {
getFactory().begin();
criteria = buildCriteria(firstResult, maxResults, criterions);
if (orders != null) {
for (Order order : orders) {
criteria.addOrder(order);
}
}
}
//log.debug("Creating Scroller...");
this.scrollableResult = criteria.scroll(ScrollMode.FORWARD_ONLY);
//log.debug("Scroller created");
}
//log.debug("Asking for next object...");
if (scrollableResult.next()) {
//log.debug(" Next object in postSelect...");
nextObject = (T)scrollableResult.get(0);
}
//log.debug(" Next object retrieved");
}
/**
* Remove is not supported.
*/
@Override
public void remove() {
throw new UnsupportedOperationException("remove not supported");
}
/**
* {@inheritDoc}
*/
@Override
public void close() {
if (scrollableResult != null) {
scrollableResult.close();
scrollableResult = null;
criteria = null;
nextObject = null;
getFactory().commit();
}
}
/**
* Finalizes this object by calling close().
* @see java.lang.Object#finalize()
*/
@Override
protected void finalize() throws Throwable {
close();
super.finalize();
}
}
}