/*
* 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.jdbc2.bridge;

import org.jboss.ejb.plugins.cmp.bridge.SelectorBridge;
import org.jboss.ejb.plugins.cmp.jdbc2.QueryCommand;
import org.jboss.ejb.plugins.cmp.jdbc2.JDBCStoreManager2;
import org.jboss.ejb.plugins.cmp.jdbc2.schema.Schema;
import org.jboss.ejb.plugins.cmp.jdbc.metadata.JDBCQueryMetaData;
import org.jboss.ejb.EntityEnterpriseContext;
import org.jboss.ejb.EntityContainer;
import org.jboss.ejb.GenericEntityObjectFactory;

import javax.ejb.FinderException;
import javax.transaction.Transaction;
import javax.transaction.TransactionManager;
import java.lang.reflect.Method;
import java.util.Collection;

/**
 * @author <a href="mailto:alex@jboss.org">Alexey Loubyansky</a>
 * @version <tt>$Revision$</tt>
 */
public class EJBSelectBridge
   implements SelectorBridge
{
   private final static byte SINGLE = 0;
   private final static byte COLLECTION = 2;

   private final JDBCQueryMetaData metadata;
   private final QueryCommand command;
   private final byte returnType;
   private final Schema schema;
   private boolean syncBeforeSelect;
   private TransactionManager tm;

   public EJBSelectBridge(EntityContainer container, Schema schema, JDBCQueryMetaData metadata, QueryCommand command)
   {
      this.schema = schema;
      this.metadata = metadata;
      this.command = command;

      Class type = metadata.getMethod().getReturnType();
      if(Collection.class.isAssignableFrom(type))
      {
         returnType = COLLECTION;
      }
      else
      {
         returnType = SINGLE;
      }

      tm = container.getTransactionManager();
      syncBeforeSelect = !container.getBeanMetaData().getContainerConfiguration().getSyncOnCommitOnly();
   }

   // BridgeInvoker implementation

   public Object invoke(EntityEnterpriseContext instance, Method method, Object[] args)
      throws Exception
   {
      Transaction tx = (instance != null ? instance.getTransaction() : tm.getTransaction());

      if(syncBeforeSelect)
      {
         EntityContainer.synchronizeEntitiesWithinTransaction(tx);
      }

      return execute(args);
   }

   // SelectorBridge implementation

   public String getSelectorName()
   {
      return metadata.getMethod().getName();
   }

   public Method getMethod()
   {
      return metadata.getMethod();
   }

   public Object execute(Object[] args) throws FinderException
   {
      JDBCStoreManager2 manager = command.getStoreManager();
      GenericEntityObjectFactory factory = (metadata.isResultTypeMappingLocal() ?
         (GenericEntityObjectFactory)manager.getContainer().getLocalProxyFactory() : manager.getContainer().getProxyFactory());

      Object result;
      switch(returnType)
      {
         case SINGLE:
            result = command.fetchOne(schema, factory, args);
            if(result == null && getMethod().getReturnType().isPrimitive())
            {
               throw new FinderException(
                  "Cannot return null as a value of primitive type " + getMethod().getReturnType().getName()
               );
            }
            break;
         case COLLECTION:
            result = command.fetchCollection(schema, factory, args);
            break;
         default:
            throw new IllegalStateException("Unexpected return type: " + returnType);
      }
      return result;
   }
}
