package org.apache.ojb.broker.util.sequence;

 /* Copyright 2003-2005 The Apache Software Foundation

  *

  * Licensed 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 org.apache.commons.lang.SystemUtils;

 import org.apache.ojb.broker.PersistenceBroker;

 import org.apache.ojb.broker.PersistenceBrokerException;

 import org.apache.ojb.broker.metadata.JdbcTypesHelper;

 import org.apache.ojb.broker.util.logging.LoggerFactory;

 import org.apache.ojb.broker.accesslayer.ResultSetAndStatement;

 import org.apache.ojb.broker.metadata.FieldDescriptor;

 import org.apache.ojb.broker.metadata.JdbcType;

 import org.apache.ojb.broker.query.Query;

 import java.sql.SQLException;

 /**

  * An Implementation Class that will retrieve a valid new value

  * for a PK field that is of type 'uniqueidentifier'. Since values

  * for these types are generated through a 'newid()' call to

  * MSSQL Server, this class is only valid for MSSQL Server 7.0 and up.

  * <br/>

  * This SequenceManager can be used for any classes that have their PK

  * defined as a 'uniqueidetifier'

  *

  * @author <a href="mailto:aclute825@hotmail.com">Andrew Clute</a>

  * @version $Id: SequenceManagerMSSQLGuidImpl.java,v 1.1 2007-08-24 22:17:29 ewestfal Exp $

  */

 public class SequenceManagerMSSQLGuidImpl extends AbstractSequenceManager

 {

     private static final JdbcType JDBC_TYPE_VARCHAR = JdbcTypesHelper.getJdbcTypeByName("varchar");

     /**

      * Constructor used by

      * {@link org.apache.ojb.broker.util.sequence.SequenceManagerFactory}

      *

      * @param broker  PB instance to perform the

      * id generation.

      */

     public SequenceManagerMSSQLGuidImpl(PersistenceBroker broker)

     {

         super(broker);

     }

     public Object getUniqueValue(FieldDescriptor field) throws SequenceManagerException

     {

         // only works for VARCHAR fields

         if(!field.getJdbcType().equals(JDBC_TYPE_VARCHAR))

         {

             throw new SequenceManagerException("This implementation only works with fields defined" +

                     " as VARCHAR, but given field was " + (field != null ? field.getJdbcType() : null));

         }

         Object result = getUniqueString(field);

         // perform a sql to java conversion here, so that clients do

         // not see any db specific values

         result = field.getFieldConversion().sqlToJava(result);

         return result;

     }

     /**

      * returns a unique String for given field.

      * the returned uid is unique accross all tables.

      */

     protected String getUniqueString(FieldDescriptor field) throws SequenceManagerException

     {

         ResultSetAndStatement rsStmt = null;

         String returnValue = null;

         try

         {

             rsStmt = getBrokerForClass().serviceJdbcAccess().executeSQL(

                     "select newid()", field.getClassDescriptor(), Query.NOT_SCROLLABLE);

             if (rsStmt.m_rs.next())

             {

                 returnValue = rsStmt.m_rs.getString(1);

             }

             else

             {

                 LoggerFactory.getDefaultLogger().error(this.getClass()

                         + ": Can't lookup new oid for field " + field);

             }

         }

         catch (PersistenceBrokerException e)

         {

             throw new SequenceManagerException(e);

         }

         catch (SQLException e)

         {

             throw new SequenceManagerException(e);

         }

         finally

         {

             // close the used resources

             if (rsStmt != null) rsStmt.close();

         }

         return returnValue;

     }

     /**

      * Returns a new unique int for the given Class and fieldname.

      */

     protected int getUniqueId(FieldDescriptor field) throws SequenceManagerException

     {

         throw new SequenceManagerException(

                 SystemUtils.LINE_SEPARATOR +

                 "Failure attempting to retrieve a Guid for a field that is an int -- field should be returned as a VARCHAR");

     }

     /**

      * Returns a new unique int for the given Class and fieldname.

      */

     protected long getUniqueLong(FieldDescriptor field) throws SequenceManagerException

     {

         throw new SequenceManagerException(

                 SystemUtils.LINE_SEPARATOR +

                 "Failure attempting to retrieve a Guid for a field that is a long -- field should be returned as a VARCHAR");

     }

     // TODO: never used? remove?

 //    /**

 //     * returns a unique Object for class clazz and field fieldName.

 //     * the returned Object is unique accross all tables in the extent of clazz.

 //     */

 //    protected Object getUniqueObject(FieldDescriptor field) throws SequenceManagerException

 //    {

 //        return getUniqueString(field);

 //    }

 }