import javax.xml.parsers.*;

import org.w3c.dom.*;

import org.xml.sax.*;

import java.io.*;

public class dbxmlparser

{

    static  string  xmlfile;

    public dbxmlparser(string filename)

    {

        xmlfile=filename;

    }

    public static element loaddocument()

    {

        try

        {

            //工厂

            documentbuilderfactory dcfactory=documentbuilderfactory.newinstance();

            //文档构造器

            documentbuilder db=dcfactory.newdocumentbuilder();

            //构造的文档

            document doc=db.parse(xmlfile);

            //根元素

            element root=doc.getdocumentelement();

            return root;

            }catch( parserconfigurationexception e){

            system.out.println("parserconfigurationexception");

            e.printstacktrace();

        }catch(ioexception e)      {

            system.out.println("ioexception ");

            e.printstacktrace();

        }catch(saxexception e)     {

            system.out.println("saxexception ");

            e.printstacktrace();

        }catch(exception e) {

            e.printstacktrace();

        }

        return null;

    }

    public connpara getsource()

    {

        element root=loaddocument();

        if( root==null) {  return null;   }

        nodelist nodes=root.getelementsbytagname("source");

        if(nodes.getlength()>0)

        {      

            node node=nodes.item(0);

            string connclass=getchildelementvalue(node,"class");

            string url=getchildelementvalue(node,"url");

            string username=getchildelementvalue(node,"user");

           string password=getchildelementvalue(node,"password");

            return new connpara(connclass,url,username,password);

        }

        return null;      

    }  

    public  connpara getdest()

    {

        element root=loaddocument();

        if( root==null) return null;

        nodelist nodes=root.getelementsbytagname("dest");

        if(nodes.getlength()>0)

        {      

            node node=nodes.item(0);

            string connclass=getchildelementvalue(node,"class");

            string url=getchildelementvalue(node,"url");

            string username=getchildelementvalue(node,"user");

            string password=getchildelementvalue(node,"password");

            return new connpara(connclass,url,username,password);

        }

        return null;      

    }

    //得到子元素的值

    private  string getchildelementvalue(node node,string subtagname)

    {

            string returnstring = "";

            if(node != null)

            {

                nodelist children = node.getchildnodes();

                for(int innerloop = 0; innerloop < children.getlength(); innerloop++)

                {

                    node child = children.item(innerloop);

                    if(child == null || child.getnodename() == null || !child.getnodename().equals(subtagname))

                        continue;

                    node grandchild = child.getfirstchild(); 

                    if(grandchild.getnodevalue() != null)

                        return grandchild.getnodevalue();

                }

            }

            return returnstring;      

    }  
}