listfourcylindervehicles.java

本套光盘提供了本书各章实例的所需的部分源程序文件以及数据库文件。读者 需要使用JDK 1.4(必需）版

// 厂商实现的PersistenceManagerFactory
import com.solarmetric.kodo.impl.jdbc.JDBCPersistenceManagerFactory;
import javax.jdo.Extent;
import javax.jdo.PersistenceManager;
import javax.jdo.PersistenceManagerFactory;
import javax.jdo.Query;
import java.util.Collection;
import java.util.Iterator;
public class ListFourCylinderVehicles {
public static void main(String[] args) {
// 厂商特定的工厂实现...
    PersistenceManagerFactory managerFactory = new JDBCPersistenceManagerFactory();
    
// 获得 a manager...
    PersistenceManager manager =managerFactory.getPersistenceManager();
     Extent ext = manager.getExtent(MotorVehicle.class, true);
// 只返回有4个cylinders的 vehicles...
   Query query = manager.newQuery(MotorVehicle.class, ext, "engine.numberOfCylinders == 4");
      Collection vehicles = (Collection) query.execute();
      Iterator iterator = vehicles.iterator();
       while (iterator.hasNext()) {
                Vehicle vehicle = (Vehicle) iterator.next();
                System.out.println("vehicle = " + vehicle);
            }
        manager.close();
        }
    }