es.alvsanand.webpage.db.dao.DAOHelper.java Source code

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Here is the source code for es.alvsanand.webpage.db.dao.DAOHelper.java

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/*
 * Copyright 2008-2010 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 es.alvsanand.webpage.db.dao;

import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;
import javax.persistence.Query;

import org.apache.commons.lang.StringUtils;
import org.compass.core.Compass;
import org.compass.core.config.CompassConfiguration;
import org.compass.core.config.CompassEnvironment;
import org.compass.gps.CompassGps;
import org.compass.gps.CompassGpsDevice;
import org.compass.gps.device.jpa.JpaGpsDevice;
import org.compass.gps.device.support.parallel.SameThreadParallelIndexExecutor;
import org.compass.gps.impl.SingleCompassGps;

import es.alvsanand.webpage.common.Logger;
import es.alvsanand.webpage.db.QueryBean;
import es.alvsanand.webpage.db.QueryBean.OrderBean;
import es.alvsanand.webpage.db.search.TextConverter;

/**
 * 
 * 
 * @author alvaro.santos
 * @date 23/11/2009
 * 
 */
public abstract class DAOHelper {
    private transient static final Logger logger = new Logger(DAOHelper.class);

    protected final static String ORDERBY_SPQL_TEXT = " ORDER BY ";
    protected final static String ASC_SPQL_TEXT = " ASCENDING";
    protected final static String DES_SPQL_TEXT = " DESCENDING";

    private static final EntityManagerFactory entityManagerFactory = Persistence
            .createEntityManagerFactory("alvsanand");

    private static Compass compass;
    private static CompassGps compassGps;

    protected EntityManager getEntityManager() {
        return entityManagerFactory.createEntityManager();
    }

    public static Compass getCompass() {
        if (compass == null) {
            logger.debug("Getting new instance of Compass");

            compass = new CompassConfiguration().setConnection("gae://index")
                    .setSetting(CompassEnvironment.ExecutorManager.EXECUTOR_MANAGER_TYPE, "disabled")
                    .addScan("es.alvsanand.webpage.model").registerConverter("textConverter",
                            com.google.appengine.api.datastore.Text.class, new TextConverter())
                    .buildCompass();

            compassGps = new SingleCompassGps(compass);

            CompassGpsDevice device = new JpaGpsDevice("appengine", entityManagerFactory);

            ((JpaGpsDevice) device).setParallelIndexExecutor(new SameThreadParallelIndexExecutor());

            compassGps.addGpsDevice(device);

            if (compass.getSearchEngineIndexManager().isLocked()) {
                compass.getSearchEngineIndexManager().releaseLocks();
            }

            compassGps.start();

            compassGps.index();
        }

        return compass;
    }

    protected Query getQuery(EntityManager entityManager, String queryName, QueryBean queryBean) {
        StringBuffer queryString = new StringBuffer(queryName);

        Query q = null;

        if (queryBean != null) {
            if (queryBean.getOrderBeans() != null) {
                for (int i = 0; i < queryBean.getOrderBeans().size(); i++) {
                    OrderBean orderBean = queryBean.getOrderBeans().get(i);

                    if (StringUtils.isEmpty(orderBean.getName())) {
                        continue;
                    }

                    if (i == 0) {
                        queryString.append(ORDERBY_SPQL_TEXT);
                    }

                    queryString.append(orderBean.getName());
                    queryString.append((orderBean.isAscendingOrder()) ? ASC_SPQL_TEXT : DES_SPQL_TEXT);
                    if (i + 1 < queryBean.getOrderBeans().size()) {
                        queryString.append(", ");
                    }
                }
            }

            q = entityManager.createQuery(queryString.toString());

            if (queryBean.getLimit() > 0) {
                q.setMaxResults(queryBean.getLimit());
            }
            if (queryBean.getOffset() > 0) {
                q.setFirstResult(queryBean.getOffset());
            }
        } else {
            q = entityManager.createQuery(queryName);
        }

        return q;
    }

    protected Query getNamedQuery(EntityManager entityManager, String queryName, QueryBean queryBean) {
        Query q = entityManager.createNamedQuery(queryName);

        if (queryBean != null) {
            if (queryBean.getLimit() > 0) {
                q.setMaxResults(queryBean.getLimit());
            }
            if (queryBean.getOffset() > 0) {
                q.setFirstResult(queryBean.getOffset());
            }
        }

        return q;
    }
}