nl.intercommit.weaves.grid.HibernatePagedGridDataSource.java Source code

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Here is the source code for nl.intercommit.weaves.grid.HibernatePagedGridDataSource.java

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/*  Copyright 2014 InterCommIT b.v.
*
*  This file is part of the "Weaves" project hosted on https://github.com/intercommit/Weaves
*
*  Weaves is free software: you can redistribute it and/or modify
*  it under the terms of the GNU Lesser General Public License as published by
*  the Free Software Foundation, either version 3 of the License, or
*  any later version.
*
*  Weaves is distributed in the hope that it will be useful,
*  but WITHOUT ANY WARRANTY; without even the implied warranty of
*  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
*  GNU Lesser General Public License for more details.
*
*  You should have received a copy of the GNU Lesser General Public License
*  along with Weaves.  If not, see <http://www.gnu.org/licenses/>.
*
*/
package nl.intercommit.weaves.grid;

import java.util.ArrayList;
import java.util.List;

import javax.persistence.EntityExistsException;

import org.apache.tapestry5.grid.SortConstraint;
import org.apache.tapestry5.ioc.internal.util.TapestryException;
import org.hibernate.Criteria;
import org.hibernate.Session;
import org.hibernate.TransientObjectException;
import org.hibernate.criterion.Order;

/**
 * A paged hibernate grid source.
 * 
 * When you want to enable checkboxes on the grid, the only allowed entitytypes are the ones with a Long as primary key ! 
 * Otherwise you can also use composite keys
 *
 */
public class HibernatePagedGridDataSource<T> extends PagedGridDataSource<T> {

    private final Session hibernateSession;
    private Criteria crit = null;

    public HibernatePagedGridDataSource(final Session session, final Class<T> entityType) {
        super(entityType);
        hibernateSession = session;
        if (session.getSessionFactory().getClassMetadata(entityType) == null) {
            throw new TapestryException("This entity [" + entityType + "] is not managed by the given session",
                    this, new EntityExistsException());
        }
    }

    public Criteria getCriteria() {
        if (crit == null) {
            crit = hibernateSession.createCriteria(getRowType());

            if (hibernateSession.getCacheMode().isGetEnabled()) {
                crit.setCacheable(true);
            }
        }
        return crit;
    }

    public List<T> fetchResult(int startIndex, int endIndexPlusOne, List<SortConstraint> sortConstraints) {

        // We just assume that the property names in the SortContraint match the Hibernate
        // properties.

        applyFiltering();

        final List<String> orderedFields = new ArrayList<String>();

        for (final SortConstraint constraint : sortConstraints) {

            final String propertyName = constraint.getPropertyModel().getPropertyName();
            if (!orderedFields.contains(propertyName)) {
                orderedFields.add(propertyName);
                switch (constraint.getColumnSort()) {

                case ASCENDING:

                    getCriteria().addOrder(Order.asc(propertyName));
                    break;

                case DESCENDING:
                    getCriteria().addOrder(Order.desc(propertyName));
                    break;

                default:
                }
            }
        }
        getCriteria().setFirstResult(startIndex).setMaxResults(endIndexPlusOne - startIndex + 1);
        return getCriteria().list();
    }

    @Override
    public Object getIdentifierForRowValue(final Object rowObject) {
        try {
            return hibernateSession.getIdentifier(rowObject);
        } catch (TransientObjectException toe) {
            return null;
        }

    }

    @Override
    public Class<?> getRowIdClass() {
        return Long.class;
    }
}