lastusedstrategy.java

主要考察的是资源池的设计和实现

package ServerImpl;
import java.util.*;
public class lastUsedStrategy implements Strategy {
    Hashtable unused=null;
    ArrayList list=new ArrayList();
    public Object getObject(String id, ResourcePool pool) throws Exception{           
        Hashtable unused = pool.getUnused();
        Enumeration e = unused.keys();
        Object lastobj=null,obj;
        Resource rs;
        Resource lastRs = new Resource("base",0);
        while( e.hasMoreElements() ){
            obj = e.nextElement();   
            rs=(Resource)unused.get(obj);
            if(rs.getObjectID().equals(id) && rs.getLastusedtime()>lastRs.getLastusedtime()){
               lastobj=obj;
               lastRs=rs;
            }
        }
        if(lastRs.getLastusedtime()==0)
            return null;
        else
            return lastobj;   
    }
}