db4odriver.java

个人感觉非常不错的poleperst-acid

/* 
This file is part of the PolePosition database benchmark
http://www.polepos.org

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.

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 org.polepos.teams.db4o;

import org.polepos.framework.*;

import com.db4o.*;
import com.db4o.ext.*;
import com.db4o.query.*;


/**
 * @author Herkules
 */
public abstract class Db4oDriver extends Driver{
    
	private ExtObjectContainer mDB;

	public void takeSeatIn( Car car , TurnSetup setup) throws CarMotorFailureException{
        super.takeSeatIn(car, setup);
		((Db4oCar)car).initialize();
	}

	public void prepare(){
		mDB = ((Db4oCar)car()).createObjectContainer();		
	}
	
	public void backToPit(){
		mDB.close();
        
        // give the weak reference collector thread time to end
        try {
            Thread.sleep(500);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
	}
	
	public ExtObjectContainer db(){
		return mDB;
	}
    
    protected void doQuery( Query q ){
        ObjectSet result = q.execute();
        while ( result.hasNext() ){
            Object o = result.next();
            if(o instanceof CheckSummable){
                addToCheckSum(((CheckSummable)o).checkSum());
            }
        }
    }
    
    protected void readExtent(Class clazz){
        Query q = db().query();
        q.constrain(clazz);
        doQuery(q);
    }
    
    protected void begin(){
        // db4o always works in a transaction so a begin call
        // is not needed.
    }
    
    protected void commit(){
        mDB.commit();
    }
    
    protected void store(Object obj){
        mDB.set(obj);
    }
}