/*
    * $Source$
    * $Revision$
    *
    * 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";
   }
 }