/*
 * JBoss, Home of Professional Open Source
 * Copyright 2005, JBoss Inc., and individual contributors as indicated
 * by the @authors tag. See the copyright.txt in the distribution for a
 * full listing of individual contributors.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */
package org.jboss.ejb.plugins.cmp.jdbc.keygen;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import javax.ejb.EJBException;

import org.jboss.deployment.DeploymentException;
import org.jboss.ejb.EntityEnterpriseContext;
import org.jboss.ejb.plugins.cmp.jdbc.JDBCIdentityColumnCreateCommand;
import org.jboss.ejb.plugins.cmp.jdbc.JDBCStoreManager;
import org.jboss.ejb.plugins.cmp.jdbc.JDBCUtil;
import org.jboss.ejb.plugins.cmp.jdbc.SQLUtil;
import org.jboss.ejb.plugins.cmp.jdbc.metadata.JDBCEntityCommandMetaData;

/**
 * Create command for PostgreSQL that fetches the currval of the sequence
 * associated with a SERIAL column in this table.
 * 
 * @author <a href="mailto:jeremy@boynes.com">Jeremy Boynes</a>
 */
public class JDBCPostgreSQLCreateCommand extends JDBCIdentityColumnCreateCommand
{
   private String sequence;
   private String sequenceSQL;

   public void init(JDBCStoreManager manager) throws DeploymentException
   {
      super.init(manager);
   }

   protected void initEntityCommand(JDBCEntityCommandMetaData entityCommand) throws DeploymentException
   {
      super.initEntityCommand(entityCommand);
      sequence = entityCommand.getAttribute("sequence");
      if (sequence == null) {
         sequence = entity.getQualifiedTableName()
            + '_' + SQLUtil.getColumnNamesClause(pkField, new StringBuffer(20))
            + "_seq";
      }
      sequenceSQL = "SELECT currval('"+sequence+"')";
      if (debug) {
         log.debug("SEQUENCE SQL is :"+sequenceSQL);
      }
   }

   protected int executeInsert(int paramIndex, PreparedStatement ps, EntityEnterpriseContext ctx) throws SQLException
   {
      int rows = ps.executeUpdate();

      Statement s = null;
      ResultSet rs = null;
      try {
         if (trace) {
            log.trace("Executing SQL :"+sequenceSQL);
         }
         Connection c = ps.getConnection();
         s = c.createStatement();
         rs = s.executeQuery(sequenceSQL);
         if (!rs.next()) {
            throw new EJBException("sequence sql returned an empty ResultSet");
         }
         pkField.loadInstanceResults(rs, 1, ctx);
      } catch (RuntimeException e) {
         throw e;
      } catch (Exception e) {
         // throw EJBException to force a rollback as the row has been inserted
         throw new EJBException("Error extracting generated keys", e);
      } finally {
         JDBCUtil.safeClose(rs);
         JDBCUtil.safeClose(s);
      }

      return rows;
   }
}
