Source code: org/fencedb/base/DBAccess.java

   
   package org.fencedb.base;
   
   import org.odmg.Implementation;
   import org.odmg.Database;
   import org.odmg.ODMGException;
   import org.odmg.OQLQuery;
   import org.odmg.Transaction;
   import org.odmg.DList;
  import org.odmg.QueryException;
  
  import java.util.Vector;
  import java.util.List;
  
  import org.apache.ojb.odmg.OJB;
  
  /**
   *  Description of the Class
   *
   * @author  vico
   * @created  June 7, 2003
   */
  public class DBAccess
  {
  
      private static DBAccess self = null;
  
      private Implementation odmg;
      private Database db;
  
  
      /**
       *Constructor for the DBAccess object
       */
      public DBAccess()
      {
          if (self == null) {
              // get odmg facade instance
              odmg = OJB.getInstance();
              db = odmg.newDatabase();
              //open database
              try {
                  db.open("default", Database.OPEN_READ_WRITE);
              }
              catch (ODMGException ex) {
                  ex.printStackTrace();
              }
              self = this;
          }
      }
  
  
      /**
       *  Gets the instance attribute of the DBAccess object
       *
       * @return  The instance value
       */
      public static DBAccess getInstance()
      {
          if (self != null) {
              return self;
          }
          else {
              return new DBAccess();
          }
      }
  
  
      /**
       *  Gets the odmg attribute of the DBAccess object
       *
       * @return  The odmg value
       */
      public Implementation getOdmg()
      {
          return odmg;
      }
  
  
      /**
       *  Description of the Method
       *
       * @param  oqlQuery Description of the Parameter
       * @param  args Description of the Parameter
       * @return  Description of the Return Value
       * @exception  QueryException Description of the Exception
       */
      public List runOQL(String oqlQuery, Vector args)
          throws QueryException
      {
  
          Transaction tx = getInstance().getOdmg().newTransaction();
          tx.begin();
          OQLQuery query = getInstance().getOdmg().newOQLQuery();
          query.create(oqlQuery);
          if (args != null) {
              for (int i = 0, size = args.size(); i < size; i++) {
                  query.bind(args.elementAt(i));
              }
         }
         DList result = (DList)query.execute();
         tx.commit();
         return result;
     }
 
 
     /**
      *  Description of the Method
      *
      * @param  oqlQuery Description of the Parameter
      * @return  Description of the Return Value
      * @exception  QueryException Description of the Exception
      */
     public List runOQL(String oqlQuery)
         throws QueryException
     {
         return runOQL(oqlQuery, null);
     }
 
 }