util.java

db4o db4o是一个嵌入式的开源对象数据库引擎.对于Java与.NET开发者来说都是一个非常好的对象持久化工具. db4o性能高并且安装简单.

package com.db4o.f1;

import com.db4o.*;


public class Util {
    public final static String YAPFILENAME="formula1.yap";

    public static void listResult(ObjectSet result) {
        System.out.println(result.size());
        while(result.hasNext()) {
            System.out.println(result.next());
        }
    }
    
    public static void listResult(java.util.List result){
    	System.out.println(result.size());
    	for(int x = 0; x < result.size(); x++)
    		System.out.println(result.get(x));
    }
    
    public static void listRefreshedResult(ObjectContainer container,ObjectSet result,int depth) {
        System.out.println(result.size());
        while(result.hasNext()) {
            Object obj = result.next();
            container.ext().refresh(obj, depth);
            System.out.println(obj);
        }
    }
    
    public static void retrieveAll(ObjectContainer db){
        ObjectSet result=db.get(new Object());
        listResult(result);
    }
    
    public static void deleteAll(ObjectContainer db) {
        ObjectSet result=db.get(new Object());
        while(result.hasNext()) {
            db.delete(result.next());
        }
    }
}