/*
// $Id: //open/dev/farrago/src/net/sf/farrago/namespace/mdr/MedMdrClassExtent.java#13 $
// Farrago is an extensible data management system.
// Copyright (C) 2005-2009 The Eigenbase Project
// Copyright (C) 2005-2009 SQLstream, Inc.
// Copyright (C) 2005-2009 LucidEra, Inc.
// Portions Copyright (C) 2003-2009 John V. Sichi
//
// This program is free software; you can redistribute it and/or modify it
// under the terms of the GNU General Public License as published by the Free
// Software Foundation; either version 2 of the License, or (at your option)
// any later version approved by The Eigenbase Project.
//
// This program 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 General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/
package net.sf.farrago.namespace.mdr;

import java.util.*;

import javax.jmi.model.*;
import javax.jmi.reflect.*;

import net.sf.farrago.namespace.*;
import net.sf.farrago.namespace.impl.*;
import net.sf.farrago.type.*;
import net.sf.farrago.util.*;

import org.eigenbase.rel.*;
import org.eigenbase.rel.convert.*;
import org.eigenbase.relopt.*;
import org.eigenbase.reltype.*;
import org.eigenbase.util.*;


/**
 * MedMdrClassExtent represents the relational mapping of a class's extent
 * (stored by MDR) into a queryable set of rows.
 *
 * @author John V. Sichi
 * @version $Id: //open/dev/farrago/src/net/sf/farrago/namespace/mdr/MedMdrClassExtent.java#13 $
 */
class MedMdrClassExtent
    extends MedAbstractColumnSet
{
    //~ Instance fields --------------------------------------------------------

    final MedMdrNameDirectory directory;
    final RefClass refClass;

    //~ Constructors -----------------------------------------------------------

    MedMdrClassExtent(
        MedMdrNameDirectory directory,
        FarragoTypeFactory typeFactory,
        RefClass refClass,
        String [] foreignName,
        String [] localName,
        RelDataType rowType)
    {
        super(localName, foreignName, rowType, null, null);
        this.directory = directory;
        this.refClass = refClass;
    }

    //~ Methods ----------------------------------------------------------------

    // implement RelOptTable
    public double getRowCount()
    {
        // REVIEW:  find out how expensive this is!  Once we start applying
        // filters, this is probably bad.
        return refClass.refAllOfType().size();
    }

    // implement RelOptTable
    public RelNode toRel(
        RelOptCluster cluster,
        RelOptConnection connection)
    {
        return new MedMdrClassExtentRel(cluster, this, connection);
    }
}

// End MedMdrClassExtent.java
