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;

     }

 }