com.impetus.kundera.client.ClientResolver Maven / Gradle / Ivy

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/*******************************************************************************
 * * Copyright 2012 Impetus Infotech.
 *  *
 *  * 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 com.impetus.kundera.client;

import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.impetus.kundera.PersistenceProperties;
import com.impetus.kundera.loader.ClientFactory;
import com.impetus.kundera.metadata.model.KunderaMetadata;
import com.impetus.kundera.metadata.model.PersistenceUnitMetadata;

/**
 * Resolver class for client. It instantiates client factory and discover
 * specific client.
 * 
 * @author vivek.mishra
 */
public final class ClientResolver
{

    /** The client factories. */
    static Map clientFactories = new ConcurrentHashMap();

    /** logger instance. */
    private static final Logger logger = LoggerFactory.getLogger(ClientResolver.class);

    /**
     * Gets the client.
     * 
     * @param persistenceUnit
     *            the persistence unit
     * @return the client
     */
    public static Client discoverClient(String persistenceUnit)
    {
        logger.info("Returning client instance for:" + persistenceUnit);
        ClientFactory clientFactory = clientFactories.get(persistenceUnit);
        if (clientFactory != null)
        {
            return clientFactory.getClientInstance();
        }
        throw new ClientResolverException(" No client configured for:" + persistenceUnit);
    }

    /**
     * Gets the client factory.
     * 
     * @param persistenceUnit
     *            the persistence unit
     * @return the client factory
     */
    public static ClientFactory getClientFactory(String persistenceUnit)
    {
        ClientFactory clientFactory = clientFactories.get(persistenceUnit);

        if (clientFactory != null)
            return clientFactory;

        logger.info("Initializing client factory for: " + persistenceUnit);
        PersistenceUnitMetadata persistenceUnitMetadata = KunderaMetadata.INSTANCE.getApplicationMetadata()
                .getPersistenceUnitMetadata(persistenceUnit);
        String kunderaClientFactory = persistenceUnitMetadata.getProperties().getProperty(
                PersistenceProperties.KUNDERA_CLIENT_FACTORY);

        if (kunderaClientFactory == null)
        {
            throw new ClientResolverException(
                    " is missing from persistence.xml, please provide specific client factory. e.g., ");
        }
        try
        {
            clientFactory = (ClientFactory) Class.forName(kunderaClientFactory).newInstance();
        }
        catch (InstantiationException e)
        {
            logger.error("Error while initializing client factory, Caused by: " + e.getMessage());
            throw new ClientResolverException("Couldn't instantiate class", e);
        }
        catch (IllegalAccessException e)
        {
            logger.error("Error while initializing client factory, Caused by: " + e.getMessage());
            throw new ClientResolverException(e);
        }
        catch (ClassNotFoundException e)
        {
            logger.error("Error while initializing client factory, Caused by: " + e.getMessage());
            throw new ClientResolverException(e);
        }

        if (clientFactory == null)
        {
            logger.error("Client Factory Not Configured For Specified Client Type : ");
            throw new ClientResolverException("Client Factory Not Configured For Specified Client Type.");
        }

        clientFactories.put(persistenceUnit, clientFactory);

        logger.info("Finishing factory initialization");
        return clientFactory;
    }
}