package udp;

import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.util.UUID;

/**

• UDP 提供者，用于提供服务
  */
  public class UDPProvider {

  public static void main(String args[]) throws IOException {

   String sn = UUID.randomUUID().toString();
   Provider provider = new Provider(sn);
   provider.run();
  
   //读取任意字符退出
   System.in.read();
   provider.exit();
  

  }

  private static class Provider extends Thread{

   private String SN;
   private boolean done = false;
   private DatagramSocket ds = null;
   public Provider(String sn) {
       super();
       this.SN = sn;
   }
  
   @Override
   public void run() {
       super.run();
       System.out.println("UDPProvider started.");
       try{
           ds = new DatagramSocket(20000);
           while(!done){
               //构建接收实体
               byte buf[] = new byte[512];
               final DatagramPacket receivePacket = new DatagramPacket(buf,buf.length);
               //接收
               ds.receive(receivePacket);
               //打印接收到的信息
               String IP = receivePacket.getAddress().getHostAddress();
               int PORT = receivePacket.getPort();
               int length = receivePacket.getLength();
               String data = new String(receivePacket.getData(),0,length);
               System.out.println("UDPProvider 接收到 ip: "+IP+"\tport:"+PORT+"\tLength"+length+"\tDATA"+data);
  
               int port = MessageCreator.parsePort(data);
               if(port!=-1){
                   String sendMessage = MessageCreator.buildWithPort(port);
                   byte[] udpProviderSendByte = sendMessage.getBytes();
                   DatagramPacket sendGramPacket = new DatagramPacket(udpProviderSendByte,0,udpProviderSendByte.length,
                           receivePacket.getAddress(),PORT);
                   ds.send(sendGramPacket);
               }
           }
       }catch (Exception e){
           exit();
       }finally {
           exit();
       }
   }
  
  
   public void exit(){
       done = true;
       if(ds!=null){
           System.out.println(ds.getInetAddress().getHostAddress()+"\t连接断开！");
           ds.close();
           ds = null;
       }
   }
  

  }
  }