NativeJpaHelper.java

/*
 * Copyright 2004-2009 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.compass.gps.device.jpa.extractor;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashSet;
import java.util.Set;
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.compass.core.util.ClassUtils;
import org.compass.gps.device.jpa.JpaGpsDeviceException;

/**
 * @author kimchy
 */
public abstract class NativeJpaHelper {

    private static final Log log = LogFactory.getLog(NativeJpaHelper.class);

    private static final NativeJpaExtractor[] extractors;

    static {
        ArrayList<NativeJpaExtractor> extractorsList = new ArrayList<NativeJpaExtractor>();
        try {
            ClassUtils.forName("org.springframework.orm.jpa.EntityManagerFactoryInfo", NativeJpaHelper.class.getClassLoader());
            extractorsList.add(new SpringNativeJpaExtractor());
        } catch (ClassNotFoundException e) {
            // not in classpath
        } catch (Throwable t) {
            log.warn("Faiiled to regsiter Spring native JPA extractor", t);
        }
        try {
            ClassUtils.forName("org.apache.openejb.persistence.JtaEntityManager", NativeJpaHelper.class.getClassLoader());
            extractorsList.add(new OpenEjbNativeJpaExtractor());
        } catch (ClassNotFoundException e) {
            // not in classpath
        } catch (Throwable t) {
            log.warn("Faiiled to regsiter OpenEJB native JPA extractor", t);
        }
        try {
            ClassUtils.forName("org.jboss.ejb3.entity.InjectedEntityManagerFactory", NativeJpaHelper.class.getClassLoader());
            extractorsList.add(new JBossNativeJpaExtractor());
        } catch (ClassNotFoundException e) {
            // not in classpath
        } catch (Throwable t) {
            log.warn("Faiiled to regsiter JBoss native JPA extractor", t);
        }
        try {
            ClassUtils.forName("com.sun.enterprise.util.EntityManagerFactoryWrapper", NativeJpaHelper.class.getClassLoader());
            extractorsList.add(new GlassfishNativeHibernateJpaExtractor());
        } catch (ClassNotFoundException e) {
            // not in classpath
        } catch (Throwable t) {
            log.warn("Faiiled to regsiter Glassfish native JPA extractor", t);
        }
        extractors = extractorsList.toArray(new NativeJpaExtractor[extractorsList.size()]);
        if (log.isDebugEnabled()) {
            log.debug("Using native JPA extractors " + Arrays.toString(extractors));
        }
    }

    public static interface NativeJpaCallback<T> {

        T onHibernate();

        T onTopLinkEssentials();

        T onOpenJPA();

        T onEclipseLink();

        T onUnknown();
    }

    public static <T> T detectNativeJpa(EntityManagerFactory emf, NativeJpaCallback<T> callback) throws JpaGpsDeviceException {
        EntityManagerFactory nativeEmf = extractNativeJpa(emf);

        Set interfaces = ClassUtils.getAllInterfacesAsSet(nativeEmf);
        Set<String> interfacesAsStrings = new HashSet<String>();
        for (Object anInterface : interfaces) {
            interfacesAsStrings.add(((Class) anInterface).getName());
        }
        interfacesAsStrings.add(nativeEmf.getClass().getName());

        T retVal;
        if (interfacesAsStrings.contains("org.hibernate.ejb.HibernateEntityManagerFactory")) {
            retVal = callback.onHibernate();
        } else if (interfacesAsStrings.contains("oracle.toplink.essentials.internal.ejb.cmp3.EntityManagerFactoryImpl")) {
            retVal = callback.onTopLinkEssentials();
        } else if (interfacesAsStrings.contains("org.eclipse.persistence.internal.jpa.EntityManagerFactoryImpl")) {
            retVal = callback.onEclipseLink();
        } else if (interfacesAsStrings.contains("org.apache.openjpa.persistence.OpenJPAEntityManagerFactory")) {
            retVal = callback.onOpenJPA();
        } else {
            retVal = callback.onUnknown();
        }
        return retVal;
    }

    public static EntityManagerFactory extractNativeJpa(EntityManagerFactory emf) {
        if (extractors.length == 0) {
            return emf;
        }
        EntityManagerFactory nativeEmf = emf;
        do {
            emf = nativeEmf;
            for (NativeJpaExtractor extractor : extractors) {
                nativeEmf = extractor.extractNative(nativeEmf);
            }
        } while (nativeEmf != emf);

        return nativeEmf;
    }

    public static EntityManager extractNativeJpa(EntityManager em) {
        if (extractors.length == 0) {
            return em;
        }
        EntityManager nativeEm = em;
        do {
            while (true) {
                // even though getDelegate should return the actual underlying implementation (Hibernate Session for example)
                // some app servers that wrap the EM, actually return the wrapped EM, and not the wrapped EM # getDelegate()
                Object delegate = nativeEm.getDelegate();
                if (delegate == nativeEm) {
                    break;
                }
                if (delegate instanceof EntityManager) {
                    nativeEm = (EntityManager) delegate;
                } else {
                    break;
                }
            }
            em = nativeEm;
            for (NativeJpaExtractor extractor : extractors) {
                nativeEm = extractor.extractNative(nativeEm);
            }
        } while (nativeEm != em);

        return nativeEm;
    }
}