package org.apache.torque.engine.platform;

 /*

  * Licensed to the Apache Software Foundation (ASF) under one

  * or more contributor license agreements.  See the NOTICE file

  * distributed with this work for additional information

  * regarding copyright ownership.  The ASF licenses this file

  * to you 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.

  */

 import java.util.HashMap;

 import java.util.Map;

 import org.apache.commons.logging.Log;

 import org.apache.commons.logging.LogFactory;

 /**

  * Factory class responsible for creating Platform objects that define RDBMS platform specific behaviour.

  */

 public class PlatformFactory {

         private static Map<String, Platform> platforms = new HashMap<String, Platform>();

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

         /**

          * Returns the Platform for a platform name.

          * 

          * @param dbms

          *            name of the platform

          */

         public static Platform getPlatformFor(String dbms) {

                 Platform result = null;

                 String platformName = null;

                 result = (Platform) getPlatforms().get(dbms);

                 if (result == null) {

                         try {

                                 platformName = getClassnameFor(dbms);

                                 Class<?> platformClass = Class.forName(platformName);

                                 result = (Platform) platformClass.newInstance();

                         } catch (Throwable t) {

                                 log.warn("problems with platform " + platformName + ": " + t.getMessage());

                                 log.warn("Torque will use PlatformDefaultImpl instead");

                                 result = new PlatformDefaultImpl();

                         }

                         getPlatforms().put(dbms, result); // cache the Platform

                 }

                 return result;

         }

         /**

          * compute the name of the concrete Class representing the Platform specified by <code>platform</code>

          * 

          * @param platform

          *            the name of the platform as specified in the repository

          */

         private static String getClassnameFor(String platform) {

                 String pf = "Default";

                 if (platform != null) {

                         pf = platform;

                 }

                 return "org.apache.torque.engine.platform.Platform" + pf.substring(0, 1).toUpperCase() + pf.substring(1) + "Impl";

         }

         /**

          * Gets the platforms.

          * 

          * @return Returns a HashMap

          */

         private static Map<String, Platform> getPlatforms() {

                 return platforms;

         }

 }