/**
 * Copyright (c) 2010 Yahoo! Inc. All rights reserved.
 * 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. See accompanying LICENSE file.
 */
package org.apache.oozie.service;

import org.apache.oozie.store.StoreException;
import org.apache.oozie.service.Service;
import org.apache.oozie.service.Services;
import org.apache.oozie.store.SLAStore;
import org.apache.oozie.store.Store;
import org.apache.oozie.store.WorkflowStore;
import org.apache.oozie.store.CoordinatorStore;
import org.apache.oozie.ErrorCode;
import javax.persistence.EntityManager;

/**
 * Base service for persistency of jobs and actions.
 */
public class StoreService implements Service {

    /**
     * Return instance of store.
     *
     * @return {@link Store}.
     */
    @SuppressWarnings("unchecked")
    public <S extends Store> S getStore(Class<S> klass) throws StoreException {
        if (WorkflowStore.class.equals(klass)) {
            return (S) Services.get().get(WorkflowStoreService.class).create();
        }
        else {
            if (CoordinatorStore.class.equals(klass)) {
                return (S) Services.get().get(CoordinatorStoreService.class).create();
            }
            else {
                if (SLAStore.class.equals(klass)) {
                    return (S) Services.get().get(SLAStoreService.class).create();
                }
            }
        }
        // to do add checks for other stores - coordinator and SLA stores
        throw new StoreException(ErrorCode.E0607, " can not get store StoreService.getStore(Class)");
    }

    /**
     * Return instance of store with an EntityManager pointing to an existing Store.
     *
     * @return {@link Store}.
     */
    @SuppressWarnings("unchecked")
    public <S extends Store, T extends Store> S getStore(Class<S> klass, T store) throws StoreException {
        if (WorkflowStore.class.equals(klass)) {
            return (S) Services.get().get(WorkflowStoreService.class).create(store);
        }
        else {
            if (CoordinatorStore.class.equals(klass)) {
                return (S) Services.get().get(CoordinatorStoreService.class).create(store);
            }
            else {
                if (SLAStore.class.equals(klass)) {
                    return (S) Services.get().get(SLAStoreService.class).create(store);
                }
            }
        }
        throw new StoreException(ErrorCode.E0607, " StoreService.getStore(Class, store)");
    }

    /**
     * Return the public interface of the service.
     *
     * @return {@link StoreService}.
     */
    public Class<? extends Service> getInterface() {
        return StoreService.class;
    }

    private JPAService jpaService;

    /**
     * Initializes the {@link StoreService}.
     *
     * @param services services instance.
     */
    public void init(Services services) throws ServiceException {
        jpaService = Services.get().get(JPAService.class);
        if (jpaService == null) {
            throw new ServiceException(ErrorCode.E0610);
        }
    }

    /**
     * Destroy the StoreService
     */
    public void destroy() {
    }

    /**
     * Return EntityManager
     */
    public EntityManager getEntityManager() {
        return jpaService.getEntityManager();
    }
}