package org.opensync.tools;
   
   import java.sql.Connection;
   import java.sql.DriverManager;
   import java.sql.SQLException;
   import java.sql.Statement;
   import java.util.Enumeration;
   import java.util.Vector;
   
  public class ConnectionPool {
  private int checkedOut;
  private Vector freeConnections = new Vector();
  //private String name;
  private String url;
  private String user;
  private String password;
  private int maxConns;
  private int timeOut;
  private String logfile;
  private String conversion_function;
  private String operator_concat;
  private boolean autocommit = false;
  private boolean batchmode = false;
  
    public ConnectionPool (String url, String user, String password,
    int maxConns, int initConns, int timeOut, String logFilename,String operator_concat,
    String conversion_function)throws SQLException{
      if (Utils.debug) System.out.println("ConnectionPool::ConnectionPool begin");
      this.conversion_function = conversion_function;
      this.operator_concat = operator_concat;
      this.url = url;
      this.user = user;
      this.password = password;
      this.maxConns = maxConns;
      this.timeOut = timeOut > 0 ? timeOut : 5;
      this.logfile = logFilename;
  
      initPool(initConns,logfile);
      if (Utils.debug) System.out.println("Pool created...");
    }
  
    private void initPool(int initConns, String logFile)throws SQLException {
      for (int i=0;i<initConns;i++) {
        Connection pc = newConnection();
        freeConnections.addElement(pc);
      }
    }
  
    public void setAutocommit(boolean autocommit) {
      this.autocommit = autocommit;
    }
  
    public void setBatchmode(boolean batchmode) {
      this.batchmode = batchmode;
    }
  
    public boolean getBatchmode() {
      return batchmode;
    }
  
    public Connection getConnection() throws SQLException {
      if (Utils.debug) System.out.println("connection request received...");
      return getConnection(timeOut*1000);
    }
  
    private synchronized Connection getConnection(long timeout) throws SQLException {
      long startTime = System.currentTimeMillis();
      long remaining = timeout;
      Connection conn = null;
  
      while ((conn = getPooledConnection())==null) {
        try {
          wait(remaining);
          }
        catch (InterruptedException e) {
            Utils.LogToFile(logfile,"InterruptedException: " + e.getMessage());
          }
        remaining = timeout - (System.currentTimeMillis() - startTime);
        if (remaining <= 0) {
          throw new SQLException("getConnection() timeout");
          }
        }
  
      if (!isConnectionOK(conn)) {
        return getConnection(remaining);
        }
  
      checkedOut++;
      conn.setAutoCommit(autocommit);
  
  
      try {
        if (!autocommit) conn.setTransactionIsolation(Connection.TRANSACTION_READ_UNCOMMITTED);
      } catch (SQLException localsqlex) {
        // Transaction isolation level not supported.
      }
  
  
      return conn;
   }
 
   private boolean isConnectionOK(Connection conn) {
   Statement testStmt = null;
 
     try {
       if (!conn.isClosed()) {
         testStmt = conn.createStatement();
         testStmt.close();
         }
       else return false;
       }
     catch (SQLException e) {
       Utils.SqlLogToFile("SQLException: " + e.getMessage());
       if (testStmt != null) {
         try {
           testStmt.close();
           }
         catch (SQLException se) {
             Utils.SqlLogToFile("SQLException: " + se.getMessage());
           }
         }
       return false;
       }
 
     return true;
   }
 
   private Connection getPooledConnection() throws SQLException {
 
     //System.out.println("ConnectionPool::getPooledConnection call");
 
     Connection conn = null;
     ///////////////////////////////////////////
     // Uncomment to debug connection problems
     ///////////////////////////////////////////
     //System.out.println("ConnectionPool::getPooledConnection - freeConnections.size()="+freeConnections.size());
     //try{
     //  double a = 1 / 0;
     //}catch (Exception e){
     //  e.printStackTrace();
     //}
     ///////////////////////////////////////////
     if (freeConnections.size() > 0) {
       conn = (Connection)freeConnections.firstElement();
       freeConnections.removeElementAt(0);
     }
     else if (maxConns == 0 || checkedOut < maxConns){
       //if (Utils.debug)
       System.out.println("Connections used: "+checkedOut+ " free connections: "+ (maxConns > 0 ? maxConns - checkedOut : 0));
       conn = newConnection();
     }
     return conn;
   }
 
   private Connection newConnection() throws SQLException {
 
     if (Utils.debug) System.out.println("ConnectionPool::newConnection call");
 
     Connection conn = null;
     if (user == null) conn = DriverManager.getConnection(url);
     else conn = DriverManager.getConnection(url,user,password);
     return conn;
   }
 
   public synchronized void freeConnection(Connection conn) {
 
     try {
       if (!autocommit) conn.commit();
     } catch (SQLException sqlex) {}
     if (Utils.debug)  System.out.println("ConnectionPool::freeConnection call");
     freeConnections.addElement(conn);
     checkedOut--;
     notifyAll();
   }
 
   public synchronized void release()throws SQLException{
     Enumeration allConnections = freeConnections.elements();
     while (allConnections.hasMoreElements()) {
       Connection con = (Connection)allConnections.nextElement();
       // In case of connection with autocommit set to false
       if (this.isConnectionOK(con) || !this.autocommit) con.commit();
       con.close();
     }
     freeConnections.removeAllElements();
   }
 
   public synchronized void releaseWithException()throws SQLException{
     Enumeration allConnections = freeConnections.elements();
     while (allConnections.hasMoreElements()) {
       Connection con = (Connection)allConnections.nextElement();
       // In case of connection with autocommit set to false
       if (this.isConnectionOK(con) || !this.autocommit) con.rollback();
       con.close();
     }
     freeConnections.removeAllElements();
   }
 
 
   public String getConversionFunction() {
     return conversion_function;
   }
   public String getOperatorConcat() {
     return operator_concat;
   }
 
   public String getUrl(){
     return url;
   }
 }