squareplanesolidman.java

基于面向对象的数据库编程

package operation;

import brgeometry.*;
import com.versant.trans.*;
import java.util.*;

import com.versant.fund.*;
import com.versant.trans.*;
import helper.ProBag;
import helper.rootMaker;

/**
 * <p>Title: Broundary Rrepresentaion</p>
 * <p>Description:  这是一个实现对于正方体操作的具体的类。</p>
 * 它实现了接口Manager提供了用户和数据库交互的基本操作</p>
 * <p>Copyright: Copyright (c) 2003</p>
 * <p>Company: USTC</p>
 * @author unascribed
 * @version 1.0
 */

public class SquarePlaneSolidMan
    implements Manager {

  TransSession session;
  //首先，用“RootMaker”查找到rootmaker对象，然后调用该对象的方法产生一个新的root
  rootMaker rm;

  public SquarePlaneSolidMan(TransSession session) {
    this.session = session;
    rm = (rootMaker) session.findRoot("Maker");
  }

  /* 增加一个方体 */
  public Solid create() {
    try {
      // rm = (rootMaker) session.findRoot("Maker");
      //开始一个和数据库的Session
      rm.addSquarePlaneSolidNum();
      //产生一个新的root；
      String root = rm.SquarePlaneSolidrootMaker();
      System.out.println("the root of the newly created Cuboid is :    " + root);
      SquarePlaneSolid squarePlaneSolid = new SquarePlaneSolid();
      squarePlaneSolid.setName(root);
      //持久化
      session.makeRoot(root, squarePlaneSolid);
      session.commit();
      //返回该对象的基类；
      return squarePlaneSolid;
    }
    catch (VException exception) {
      session.endSession();
      //rootMaker 新产生的root与数据库中已经有的root重复
      if (exception.getErrno() == Constants.EVJ_ROOTNAME_ALREADY_DEFINED)
        System.out.println("Root name already exists");
        //rootMaker不存在
      if (exception.getErrno() == Constants.EVJ_ROOTNAME_DOES_NOT_EXIST) {
        System.out.println("rootname does not exist");
        rm = null;
      }
      else
        throw exception;
      return null;
    }
  }

  //删除一个方体
  public void deleteByRoot(String root) {
    try {
      SquarePlaneSolid squarePlaneSolid = (SquarePlaneSolid) session.findRoot(
          root);
      VEnumeration result;
      RequireMan requireMan =new RequireMan(session );

      result=requireMan.deepSelect( root,"Cube" );
      while (result.hasMoreElements()) {
      session.deleteObject(result.nextElement());
      }

     // session.deleteObject(squarePlaneSolid);
      session.deleteRoot(root);

      rm.delSquarePlaneSolidNum();
      session.commit();
      System.out.println("delete a CoboidPlaneSolid with name  " + root);
    }
    catch (VException exception) {
      session.endSession();
      int err = exception.getErrno();
      if (err != Constants.EVJ_ROOTNAME_DOES_NOT_EXIST) {
        throw exception;
      }
    }
  }

  public Solid findByRoot(String root) {
    try {
    SquarePlaneSolid squarePlaneSolid = (SquarePlaneSolid) session.findRoot(
        root);
    session.commit();
    return squarePlaneSolid;
    }

    catch (VException exception) {
  // session.endSession();
  // Ignore error if root name does not exist
  int err = exception.getErrno();
  if (err != Constants.EVJ_ROOTNAME_DOES_NOT_EXIST) {
    throw exception;
  }
 }
  return null;
  }

}