package com.dy.testClient.tcpConnect;

import java.util.*;
import org.apache.mina.core.session.IoSession;


public class MinaConnectPool {
    /**
     * 空闲会话的池(Hashtable是线程安全的)
     */
    private static Hashtable<String , Vector<IoSession>> freeSessions = new Hashtable<String ,Vector<IoSession>>();

    /**
     * 从会话池中得到空闲的会话，如果没有空闲的会话，本着快速反应的原则，新建一个会话，不再等待繁忙会话的释放
     * @param host
     * @param port
     * @return
     * @throws Exception
     */
    public static IoSession getSession(String host , int port , int connectTimeout) throws Exception{
        Vector<IoSession> vecter = freeSessions.get(getKey(host , port)) ;
        if(vecter == null){
            vecter = new Vector<IoSession>() ;
            freeSessions.put(getKey(host , port), vecter) ;
        }

        MinaConnect con = new MinaConnect() ;

        IoSession se = popSession(vecter , con) ;
        if(se == null){
            MinaHandler handler = new MinaHandler(connectTimeout) ;
            se = createNewSession(host, port, connectTimeout, con, handler) ;
        }
        return se ;
    }

    /**
     * 将会话放回池中
     * @param host
     * @param port
     * @param se
     */
    public static void freeSession(String host , int port , IoSession se){
        if(se == null){
            return ;
        }
        Vector<IoSession> vecter = freeSessions.get(getKey(host , port)) ;
        if(vecter == null){
            vecter = new Vector<IoSession>() ;
            freeSessions.put(getKey(host , port), vecter) ;
        }
        putSession(vecter, se) ;
    }

    /**
     * 从会话池中取得空闲的会话
     * @param vecter
     * @return
     */
    private static IoSession popSession(Vector<IoSession> vecter , MinaConnect con){
        IoSession se = null ;
        while(se == null && !vecter.isEmpty()){
            se = (IoSession)vecter.firstElement() ;
            if(se != null){
                vecter.removeElementAt(0) ;
            }
            if(!con.isConnected(se)){
                se = null ;
            }
        }
        return se ;
    }

    /**
     * 放新会话
     * @param vecter
     * @param se
     */
    private static void putSession(Vector<IoSession> vecter , IoSession se){
        vecter.addElement(se) ;
    }

    /**
     * 创建新会话
     * @param host
     * @param port
     * @param connectTimeout
     * @param con
     * @return
     * @throws Exception
     */
    private static IoSession createNewSession(String host , int port , int connectTimeout, MinaConnect con , MinaHandler handler) throws Exception{
        return con.createSession(host, port, connectTimeout , handler) ;
    }

    /**
     * 得到会话池的key
     * @param url
     * @param port
     * @return
     */
    private static String getKey(String host , int port){
        return host + port ;
    }

}