org.shept.persistence.provider.hibernate.HibernateAssociationProvider.java Source code

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Here is the source code for org.shept.persistence.provider.hibernate.HibernateAssociationProvider.java

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/*
 * Copyright 2007-2011 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.shept.persistence.provider.hibernate;

import java.io.Serializable;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

import org.shept.beans.support.ReloadableAssociation;
import org.shept.persistence.provider.DaoUtils;
import org.shept.persistence.provider.DataLoadException;
import org.springframework.orm.hibernate3.support.HibernateDaoSupport;
import org.springframework.util.ReflectionUtils;

/**
 * @version $$Id: HibernateAssociationProvider.java 34 2010-08-20 16:46:49Z aha $$
 * 
 * @author Andi
 * 
 */
public class HibernateAssociationProvider extends AbstractHibernateListProvider {

    /*
     * (non-Javadoc)
     * 
     * @see
     * org.shept.persistence.provider.AbstractScrollingListProvider#loadListFirst
     * ()
     */
    @SuppressWarnings({ "rawtypes" })
    @Override
    public List<?> loadListFirst() {
        ReloadableAssociation ass = (ReloadableAssociation) getFilterDefinition();
        Object model = ass.getSourceModel();

        // reload the object again ...
        // hibernateDao.getHibernateTemplate().refresh(model) won't work, so here's a workaround ...
        // ... to get rid of this dreaded and random LazyLoadingExceptions when opening the link ...

        Object idxObj = DaoUtils.getIdValue((HibernateDaoSupport) this.dao, model);
        if (idxObj == null) {
            // can't load from database so we have nothing here ...
            // we should not use existing transient objects from the cache !
            return new ArrayList();
        }

        model = getHibernateTemplate().load(model.getClass(), (Serializable) idxObj);

        Object res = ReflectionUtils.invokeMethod(ass.getAssociationMethod(), model);
        if (!(res instanceof List)) {
            throw new DataLoadException("Could not provide the requested data '"
                    + ass.getAssociationMethod().getName() + "' from DataSource '" + ass.getSourceModel().getClass()
                    + ". Result is '" + res + "' but a List is required");
        }
        eol = true;
        return (List<?>) res;
    }

    /*
     * (non-Javadoc)
     * 
     * @see
     * org.shept.persistence.provider.AbstractScrollingListProvider#loadListNext
     * ()
     */
    @Override
    public List<?> loadListNext() {
        return Collections.emptyList();
    }

}