/*

  * $Source$

  * $Revision$

  *

  * Copyright (C) 2000 William Chesters

  *

  * Part of Melati (http://melati.org), a framework for the rapid

  * development of clean, maintainable web applications.

  *

  * Melati is free software; Permission is granted to copy, distribute

  * and/or modify this software under the terms either:

  *

  * a) the GNU General Public License as published by the Free Software

  *    Foundation; either version 2 of the License, or (at your option)

  *    any later version,

  *

  *    or

  *

  * b) any version of the Melati Software License, as published

  *    at http://melati.org

  *

  * You should have received a copy of the GNU General Public License and

  * the Melati Software License along with this program;

  * if not, write to the Free Software Foundation, Inc.,

  * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA to obtain the

  * GNU General Public License and visit http://melati.org to obtain the

  * Melati Software License.

  *

  * Feel free to contact the Developers of Melati (http://melati.org),

  * if you would like to work out a different arrangement than the options

  * outlined here.  It is our intention to allow Melati to be used by as

  * wide an audience as possible.

  *

  * This program is distributed in the hope that it will be useful,

  * but WITHOUT ANY WARRANTY; without even the implied warranty of

  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

  * GNU General Public License for more details.

  *

  * Contact details for copyright holder:

  *

  *     William Chesters <williamc At paneris.org>

  *     http://paneris.org/~williamc

  *     Obrechtstraat 114, 2517VX Den Haag, The Netherlands

  */

 package org.melati;

 import java.io.IOException;

 import java.util.Vector;

 import java.util.Properties;

 import org.melati.poem.Database;

 import org.melati.poem.PoemDatabaseFactory;

 import org.melati.util.DatabaseInitException;

 import org.melati.util.MelatiBugMelatiException;

 import org.melati.util.PropertiesUtils;

 import org.melati.util.PropertyException;

 /**

  * An object which knows how to connect to a database.

  */

 public final class LogicalDatabase {

   private LogicalDatabase() {}

   /** Properties, named for this class. */

   private static Properties databaseDefs = null;

   private static final int MAX_TRANSACTIONS_DEFAULT = 8;

   private static synchronized Properties databaseDefs() {

     if (databaseDefs == null)

       try { 

         databaseDefs =

             PropertiesUtils.fromResource(LogicalDatabase.class,

                 getPropertiesName());

       } catch (IOException e) {

         throw new MelatiBugMelatiException("Cannot open database properties file " + getPropertiesName(), e);

       }        

     return databaseDefs;

   }

   /** 

    * Retrieve the databases which have completed initialisation.

    *

    * @return a <code>Vector</code> of the initialised databases

    */

   public static Vector<Database> initialisedDatabases() {

     return PoemDatabaseFactory.initialisedDatabases();

   }

   /** 

    * Retrieve the names of the databases which have 

    * completed initialisation.

    * Note that a database which has not been used 

    * will not have been initialised.

    *

    * @return a <code>Vector</code> of the initialised database names

    */

   public static Vector<String> getInitialisedDatabaseNames() {

     return PoemDatabaseFactory.getInitialisedDatabaseNames();

   }

   /** 

    * Retrieve a database by name.

    *

    * @param name the name of the database

    * @throws DatabaseInitException if any Exception is trapped

    * @return a <code>Database</code> with the name specified

    */

   public static Database getDatabase(String name) 

       throws DatabaseInitException {

     Database db = PoemDatabaseFactory.getDatabase(name);

     if (db == null) {

       Properties defs = databaseDefs();

       String pref =  LogicalDatabase.class.getName() + "." + name + ".";

       String url = null;

       String user = null;

       String pass = null;

       String clazz = null;

       String dbmsClass = null;

       String addConstraints = null;

       String logSQL  = null;

       String logCommits = null;

       int maxTrans;

       try {

         url = PropertiesUtils.getOrDie(defs, pref + "url");

         user = PropertiesUtils.getOrDie(defs, pref + "user");

         pass = PropertiesUtils.getOrDie(defs, pref + "pass");

         clazz = PropertiesUtils.getOrDie(defs, pref + "class");

         dbmsClass = PropertiesUtils.getOrDie(defs, pref + "dbmsclass");

         addConstraints = PropertiesUtils.getOrDefault(defs, pref + "addconstraints", "false");

         logSQL = PropertiesUtils.getOrDefault(defs, pref + "logsql", "false");

         logCommits = PropertiesUtils.getOrDefault(defs, pref + "logcommits", "false");

         maxTrans = PropertiesUtils.

                          getOrDefault_int(defs, pref + "maxtransactions", MAX_TRANSACTIONS_DEFAULT);

       } catch (PropertyException e) {

         throw new DatabaseInitException(getPropertiesName(),name, e);

       }

       db = PoemDatabaseFactory.getDatabase(name, url, user, pass, 

              clazz, dbmsClass, 

              new Boolean(addConstraints).booleanValue(), 

              new Boolean(logSQL).booleanValue(), 

              new Boolean(logCommits).booleanValue(),

              maxTrans);

     }

     return db;

   }  

   /**

    * Set the databaseDefs.

    */

   public static void setDatabaseDefs(Properties databaseDefsIn) {

     databaseDefs = databaseDefsIn;

   }

   /**

    * The name used with <code>getResourceAsStream</code> to 

    * get the file and the properties within it. 

    * 

    * @return Returns the defaultPropertiesName.

    */

   public static String getPropertiesName() {

     return "org.melati.LogicalDatabase.properties";

   }

 }