poolmanager.java

cnc网通小灵通网关接口源码

package cncgw.smdb;

/**
 * <p>Title: </p>
 * <p>Description: </p>
 * <p>Copyright: Copyright (c) 2003</p>
 * <p>Company: </p>
 * @author
 * @version 1.0
 */

import java.sql.*;
import java.io.*;
import java.util.*;

import cncgw.cncMain;



/**
 * 创建一个数据连接池所需要的属性为：
 * poolname.url/poolname.user/poolname.password/poolname.maxconns/
 * poolname.initconns/poolname.Clogintimeout/poolname.Cloglevel
 */
public class PoolManager {

    static private PoolManager instance;
    static private int clients;

    public static String driver = "";
    public static String url = "";
    public static String user = "";
    public static String password = "";
    public static int initconn = 3;
    public static int maxconns = 6;
    public static int logintimeout = 10;


    private Vector drivers = new Vector();
    private Hashtable pools = new Hashtable();

    private PoolManager()
    {
     init();
    }

    public static synchronized  PoolManager getInstance()
    {
        if (instance == null) {
            instance = new PoolManager();
        }
        clients++;
        return instance;
    }

    private void init()  {

       Properties dbProps = new Properties();
       String name = "cnc";
       String driverClassName = driver;

       try {

         int init;
            try
            {
               init = initconn;
            }
            catch (NumberFormatException e)
            {
               cncMain.errorlog("Invalid initconns value " + initconn +
                             " for " + name);
               init = 0;
            }

         int max;
            try
            {
               max = maxconns;
            }
            catch (NumberFormatException e)
            {
               cncMain.errorlog("Invalid maxconns value " + maxconns +
                               " for " + name);
               max = 0;
            }

         int timeOut;
            try
            {
               timeOut = logintimeout;
            }
            catch (NumberFormatException e)
            {
               cncMain.errorlog("Invalid logintimeout value " + logintimeout +
                            " for " + name);
               timeOut = 5;
            }


         // 填充数据连接属性
         loadDriver(driverClassName);

       }
       catch (Exception e) {
            cncMain.errorlog("Can't read the properties of connection pool in config.");
            return;
       }
       addDBConnToPool(name,driverClassName,url,user,password,initconn,maxconns,logintimeout);
  }
    public void addDBConnToPool(String ConnName,String DriverClassName,String DBUrl,String DBUser,
                        String DBPassword,int InitConns,int MaxConns,int LoginTimeOut)
    {
        loadDriver(DriverClassName);
        ConnectionPool pool =
                new ConnectionPool(ConnName, DBUrl, DBUser, DBPassword,
                MaxConns, InitConns, LoginTimeOut);
        pools.put(ConnName, pool);
    }

    private void loadDriver(String driverClassName) {
        try {
            Driver driver = (Driver) Class.forName(driverClassName).newInstance();
            DriverManager.registerDriver(driver);
            drivers.addElement(driver);
            System.out.println("Registered JDBC driver " + driverClassName);
        }
        catch (Exception e) {
            System.err.println(e + "Can't register JDBC driver: " + driverClassName);
        }
    }


    public Connection getConnection(String name)
    {
        Connection conn = null;
        ConnectionPool pool = (ConnectionPool) pools.get(name);
        if (pool != null)
        {
            try
            {
                conn = pool.getConnection();
            }
            catch (SQLException e)
            {
                System.err.println(e+ "Exception getting connection from " + name);
            }
        }
        return conn;
    }

    public void freeConnection(String name, Connection con)
    {
        ConnectionPool pool = (ConnectionPool) pools.get(name);
        if (pool != null)
        {
            pool.freeConnection(con);
        }
    }

    public synchronized void release()
    {
        // Wait until called by the last client
        if (--clients != 0)
        {
            return;
        }

        Enumeration allPools = pools.elements();
        while (allPools.hasMoreElements())
        {
            ConnectionPool pool = (ConnectionPool) allPools.nextElement();
            pool.release();
        }

        Enumeration allDrivers = drivers.elements();
        while (allDrivers.hasMoreElements())
        {
            Driver driver = (Driver) allDrivers.nextElement();
//         try
//         {
//            DriverManager.deregisterDriver(driver);
//            Clog.info("Deregistered JDBC driver " +
//          .error(e +"Couldn't deregister JDBC driver: " +
//                             driver.getClass().getName());
//         }
        }
    }
}