/*

  * Copyright (c) 2004 International Decision Systems, Inc.  All Rights Reserved.

  *

  * By using this Software, You acknowledge that the Software is a valuable asset

  * and trade secret of either International Decision Systems, Inc. ("IDSI") or a

  * third party supplier of IDSI and constitutes confidential and proprietary

  * information.

  *

  * NEITHER IDSI NOR ANY AGENT OR PERSON ACTING FOR OR WITH IDSI HAS MADE OR DOES

  * MAKE ANY STATEMENTS, AFFIRMATIONS, REPRESENTATIONS OR WARRANTIES WHATSOEVER

  * TO YOU, WHETHER EXPRESS OR IMPLIED, AS TO THE SOFTWARE, THE QUALITY OR

  * CONDITION OF THE SOFTWARE, OR THE OPERATING CHARACTERISTICS OR RELIABILITY OF

  * THE SOFTWARE, OR ITS SUITABILITY FOR ANY GENERAL OR PARTICULAR PURPOSE, OR AS

  * TO ANY OTHER MATTER WHATSOEVER; ANY AND ALL OTHER WARRANTIES INCLUDING

  * WITHOUT LIMITATION ANY WARRANTIES IMPLIED BY LAW, SUCH AS THE IMPLIED

  * WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, AND TITLE,

  * USE AND NON-INFRINGEMENT; ARE HEREBY EXPRESSLY DISCLAIMED AND EXCLUDED.

 */

 package net.sourceforge.addam.ddlrun.grammars;

 import java.io.IOException;

 import java.io.InputStream;

 import java.net.URL;

 import java.sql.Connection;

 import java.sql.SQLException;

 import java.util.Enumeration;

 import java.util.Properties;

 /**

  * Used to get the correct grammar for a JDBC connection

  *

  * @author TIM3

  * @since Mar 28, 2005

  */

 public class ScriptGrammarManager {

         /**

          * Constructor.

          *

          * @todo externalize the property filename in this method.

          */

     public ScriptGrammarManager() {

             //TODO externalize this property file name

         this("net/sourceforge/addam/ddlrun/grammars/ScriptGrammars.properties");

     }

     public ScriptGrammarManager(String resourceName) {

         Enumeration resources;

         try {

             resources = ScriptGrammarManager.class.getClassLoader().getResources(resourceName);

         } catch (IOException e) {

             throw new RuntimeException("unable to load resource named " + resourceName, e);

         }

         if (!resources.hasMoreElements()) {

             throw new RuntimeException("no such resource " + resourceName);

         }

         while (resources.hasMoreElements()) {

             URL resource = (URL) resources.nextElement();

             InputStream in = null;

             try {

                 in = resource.openStream();

                 registry.load(in);

             } catch (IOException e) {

                 throw new RuntimeException("unable to load resource " + resource, e);

             } finally {

                 try {

                     if (in != null) {

                         in.close();

                     }

                 } catch (IOException e) {

                     // shouldn't happen

                     throw new RuntimeException("unable to load resource " + resource, e);

                 }

             }

         }

     }

     public ScriptGrammarManager(Properties registry) {

         this.registry.putAll(registry);

     }

     public ScriptGrammar getGrammar(Connection connection) {

         String productName = null;

         if (connection != null) {

             try {

                 productName = connection.getMetaData().getDatabaseProductName();

             } catch (SQLException e) {

                 throw new RuntimeException("unable to determine database product name", e);

             }

         }

         ScriptGrammar grammar = null;

         if (productName != null) {

             String grammarClassName = registry.getProperty(productName);

             if (grammarClassName != null) {

                 try {

                     grammar = (ScriptGrammar) Class.forName(grammarClassName).newInstance();

                 } catch (InstantiationException e) {

                     throw new RuntimeException("unable to instantiate: " + grammarClassName, e);

                 } catch (IllegalAccessException e) {

                     throw new RuntimeException("illegal access when instantiating: " + grammarClassName, e);

                 } catch (ClassNotFoundException e) {

                     throw new RuntimeException("class not found: " + grammarClassName, e);

                 }

             }

         }

         return grammar;

     }

     // for testing

     Properties getGrammarRegistry() {

         // wrap the registry so the caller can't modify it

         return new Properties(registry);

     }

     private final Properties registry = new Properties();

 }