org.esupportail.commons.dao.AbstractHibernateQueryPaginator.java Source code

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Here is the source code for org.esupportail.commons.dao.AbstractHibernateQueryPaginator.java

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/**
 * Copyright (C) 2009 GIP RECIA http://www.recia.fr
 * @Author (C) 2009 GIP RECIA <contact@recia.fr>
 * @Contributor (C) 2009 SOPRA http://www.sopragroup.com/
 * @Contributor (C) 2011 Pierre Legay <pierre.legay@recia.fr>
 *
 * 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.
 */
/**
 * ESUP-Portail Commons - Copyright (c) 2006-2009 ESUP-Portail consortium.
 */
package org.esupportail.commons.dao;

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

import org.esupportail.commons.services.logging.Logger;
import org.esupportail.commons.services.logging.LoggerImpl;
import org.hibernate.Query;
import org.hibernate.ScrollableResults;

/** 
 * A Hibernate paginator that directly relies on a HQL query.
 * @param <E> the class of the results
 */
@SuppressWarnings("serial")
public abstract class AbstractHibernateQueryPaginator<E> extends AbstractHibernatePaginator<E> {

    /**
     * A logger.
     */
    private final Logger logger = new LoggerImpl(getClass());

    /** 
     * Constructor.
     */
    public AbstractHibernateQueryPaginator() {
        super();
    }

    /** 
     * Constructor.
     * @param daoService 
     * @param pageSizeValues 
     * @param pageSize the number of results to display on the page 
     * @deprecated use setPageSizeValues() and setDefaultPageSize() 
     */
    @Deprecated
    public AbstractHibernateQueryPaginator(final HibernateDaoService daoService, final List<Integer> pageSizeValues,
            final int pageSize) {
        super(daoService, pageSizeValues, pageSize);
    }

    /**
     * @see org.esupportail.commons.web.beans.AbstractPaginator#loadItemsInternal()
     */
    @Override
    @SuppressWarnings("unchecked")
    protected void loadItemsInternal() {
        String queryString = getQueryString();
        if (queryString == null) {
            setVisibleItems(new ArrayList<E>());
            setCurrentPageInternal(0);
            setTotalItemsCount(0);
            return;
        }
        Query query = getDaoService().getQuery(queryString);
        ScrollableResults scrollableResults = query.scroll();
        /* 
         * We set the max results to one more than the specfied pageSize to 
         * determine if any more results exist (i.e. if there is a next page 
         * to display). The result set is trimmed down to just the pageSize 
         * before being displayed later (in getList()). 
         */
        if (logger.isDebugEnabled()) {
            logger.debug("executing " + query.getQueryString() + "...");
        }
        query.setFirstResult(getCurrentPageInternal() * getPageSize());
        query.setMaxResults(getPageSize());
        setVisibleItems(query.list());
        // the total number of results is computed here since scrolling is not allowed when rendering
        scrollableResults.last();
        setTotalItemsCount(scrollableResults.getRowNumber() + 1);
        if (logger.isDebugEnabled()) {
            logger.debug("done.");
        }
        if (getVisibleItemsCountInternal() == 0 && getTotalItemsCountInternal() != 0) {
            setCurrentPageInternal(getLastPageNumberInternal());
            loadItemsInternal();
        }
        updateLoadTime();
    }

    /**
     * @return the query string.
     */
    protected abstract String getQueryString();

}