no.magott.spring.FetchJoinTests.java Source code

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Here is the source code for no.magott.spring.FetchJoinTests.java

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/*
 * Copyright 2006-2007 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 no.magott.spring;

import static org.hamcrest.CoreMatchers.equalTo;
import static org.junit.Assert.assertNotNull;
import static org.junit.Assert.assertThat;

import java.util.Iterator;

import org.hibernate.Query;
import org.hibernate.ScrollableResults;
import org.hibernate.SessionFactory;
import org.hibernate.StatelessSession;
import org.hibernate.classic.Session;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import org.springframework.transaction.PlatformTransactionManager;
import org.springframework.transaction.TransactionStatus;
import org.springframework.transaction.support.DefaultTransactionDefinition;

@ContextConfiguration
@RunWith(SpringJUnit4ClassRunner.class)
public class FetchJoinTests {

    @Autowired
    private SessionFactory sessionFactory;

    @Autowired
    private PlatformTransactionManager transactionManager;

    @Test
    public void testScrollVsListOnQuery() throws Exception {
        TransactionStatus transaction = transactionManager.getTransaction(new DefaultTransactionDefinition());
        Session session = sessionFactory.getCurrentSession();
        Order order = new Order();
        order.getItems().add(createItem("Product 1"));
        order.getItems().add(createItem("Product 2"));
        order.getItems().add(createItem("Product 3"));
        session.save(order);
        session.flush();
        assertNotNull(order.getId());
        order = new Order();
        order.getItems().add(createItem("Product 4"));
        order.getItems().add(createItem("Product 5"));
        order.getItems().add(createItem("Product 6"));
        session.save(order);
        session.flush();
        assertNotNull(order.getId());
        transactionManager.commit(transaction);

        transaction = transactionManager.getTransaction(new DefaultTransactionDefinition());
        StatelessSession stateless = sessionFactory.openStatelessSession();

        Query query = stateless.createQuery("select o FROM Order AS o LEFT JOIN FETCH o.items");
        int count = query.list().size();

        //Strange!
        assertThat(count, equalTo(6));

        count = getCountFromScrollableResults(query);

        //As expected
        assertThat(count, equalTo(2));

        System.out.println(count);
        transactionManager.commit(transaction);
    }

    private int getCountFromScrollableResults(Query query) {
        ScrollableResults scrollableResults = query.scroll();
        int count;
        for (count = 0; scrollableResults.next(); count++) {
        }
        return count;
    }

    private Item createItem(String string) {
        Item item = new Item();
        item.setProduct(string);
        return item;
    }

}