/*
* JBoss, Home of Professional Open Source.
* Copyright 2008, Red Hat Middleware LLC, and individual contributors
* as indicated by the @author tags. See the copyright.txt file 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;
import java.lang.reflect.Method;
import java.lang.reflect.InvocationTargetException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Enumeration;
import java.util.List;
import javax.ejb.FinderException;
import org.jboss.ejb.EntityEnterpriseContext;
import org.jboss.ejb.GenericEntityObjectFactory;
import org.jboss.ejb.plugins.cmp.jdbc.metadata.JDBCReadAheadMetaData;
import org.jboss.logging.Logger;
/**
* CMPStoreManager CustomFindByEntitiesCommand.
* Implements bridge for custom implemented finders in container managed entity
* beans. These methods are called ejbFindX in the EJB implementation class,
* where X can be anything. Such methods are called findX in the Home and/or
* the LocalHome interface.
*
* @see org.jboss.ejb.plugins.cmp.jdbc.JDBCFindEntitiesCommand
* @author <a href="mailto:michel.anke@wolmail.nl">Michel de Groot</a>
* @author <a href="mailto:john-jboss@freeborg.com">John Freeborg</a>
* @version $Revision: 81030 $
*/
public final class JDBCCustomFinderQuery implements JDBCQueryCommand
{
private final Logger log;
private final Method finderMethod;
private final JDBCReadAheadMetaData readAheadMetaData;
private final ReadAheadCache readAheadCache;
private final JDBCStoreManager manager;
/**
* Constructs a command which can handle multiple entity finders
* that are BMP implemented.
* @param finderMethod the EJB finder method implementation
*/
public JDBCCustomFinderQuery(JDBCStoreManager manager, Method finderMethod)
{
this.finderMethod = finderMethod;
this.manager = manager;
JDBCReadAheadMetaData readAheadMetaData = manager.getMetaData().getReadAhead();
if((readAheadMetaData != null) && readAheadMetaData.isOnLoad())
{
this.readAheadCache = manager.getReadAheadCache();
this.readAheadMetaData = readAheadMetaData;
}
else
{
this.readAheadCache = null;
this.readAheadMetaData = null;
}
this.log = Logger.getLogger(
this.getClass().getName() +
"." +
manager.getMetaData().getName() +
"." +
finderMethod.getName());
if(log.isDebugEnabled())
log.debug("Finder: Custom finder " + finderMethod.getName());
}
public JDBCStoreManager getSelectManager()
{
return manager;
}
public Collection execute(Method unused,
Object[] args,
EntityEnterpriseContext ctx,
GenericEntityObjectFactory factory)
throws FinderException
{
try
{
// invoke implementation method on ejb instance
Object value = finderMethod.invoke(ctx.getInstance(), args);
// if expected return type is Collection, return as is
// if expected return type is not Collection, wrap value in Collection
if(value instanceof Enumeration)
{
Enumeration enumeration = (Enumeration)value;
List result = new ArrayList();
while(enumeration.hasMoreElements())
{
result.add(enumeration.nextElement());
}
cacheResults(result);
return GenericEntityObjectFactory.UTIL.getEntityCollection(factory, result);
}
else if(value instanceof Collection)
{
List result;
if (value instanceof List)
result = (List)value;
else
result = new ArrayList((Collection)value);
cacheResults(result);
return GenericEntityObjectFactory.UTIL.getEntityCollection(factory, result);
}
else
{
// Don't bother trying to cache this
return Collections.singleton(factory.getEntityEJBObject(value));
}
}
catch(IllegalAccessException e)
{
log.error("Error invoking custom finder " + finderMethod.getName(), e);
throw new FinderException("Unable to access finder implementation: " +
finderMethod.getName());
}
catch(IllegalArgumentException e)
{
log.error("Error invoking custom finder " + finderMethod.getName(), e);
throw new FinderException("Illegal arguments for finder " +
"implementation: " + finderMethod.getName());
}
catch(InvocationTargetException e)
{
// Throw the exception if its a FinderException
Throwable ex = e.getTargetException();
if( ex instanceof FinderException )
{
throw (FinderException) ex;
}
else
{
throw new FinderException("Errror invoking cutom finder " +
finderMethod.getName() + ": " + ex);
}
}
}
private void cacheResults(List listOfPKs)
{
// the on-load read ahead cache strategy is the only one that makes
// sense to support for custom finders since all we have is a list of
// primary keys.
if(readAheadCache != null)
{
readAheadCache.addFinderResults(listOfPKs, readAheadMetaData);
}
}
}