pooledconnection.java

SAP这个系统的一个转换器

//
//
package com.scxh.eei.sql;

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

import javax.sql.ConnectionEvent;
import javax.sql.ConnectionEventListener;
import com.scxh.eei.sql.proxy.*;

/**
 *  implementation of the <code>PooledConnection</code> interface.
 *
 * @version $Id: PooledConnection.java,v 1.11 2005/02/01 23:52:50 Exp $
 */
public class PooledConnection implements javax.sql.PooledConnection {
    private ArrayList listeners = new ArrayList();

    protected Connection _connection;
    protected ConnectionProxy connection;

    public PooledConnection(Connection connection) {
      this._connection=connection;
    }

    /**
     * Adds the specified listener to the list.
     *
     * @see #fireConnectionEvent
     * @see #removeConnectionEventListener
     */
    public synchronized void addConnectionEventListener(ConnectionEventListener listener) {
        // Clone the list of listeners to avoid concurrent modifications. See
        // bug [1113040] Small bug in net.sourceforge.jtds.jdbcx.PooledConnection
        // for a description of how these can occur. The method still needs to
        // be synchronized to prevent race conditions.
        listeners = (ArrayList) listeners.clone();
        // Now add the listener to the new, cloned list
        listeners.add(listener);
    }

    /**
     * Closes the database connection.
     *
     * @throws SQLException if an error occurs
     */
    public synchronized void close() throws SQLException {
        connection.close();
        connection = null; // 垃圾收集的连接
    }

    /**
     * Fires a new connection event on all listeners.
     *
     * @param closed <code>true</code> if <code>close</code> has been called on the
     *        connection; <code>false</code> if the <code>sqlException</code> represents
     *        an error where the connection may not longer be used.
     * @param sqlException the SQLException to pass to the listeners
     */
    public synchronized void fireConnectionEvent(boolean closed, SQLException sqlException) {
        if (listeners.size() > 0) {
            ConnectionEvent connectionEvent = new ConnectionEvent(this, sqlException);
            Iterator iterator = listeners.iterator();

            while (iterator.hasNext()) {
                ConnectionEventListener listener = (ConnectionEventListener) iterator.next();

                if (closed) {
                    if(listener!=null)
                       listener.connectionClosed(connectionEvent);
                } else {
                    try {
                        if (connection == null || connection.isClosed()) {
                            listener.connectionErrorOccurred(connectionEvent);
                        }
                    } catch (SQLException ex) {
                        // Will never occur
                    }
                }
            }
        }
    }

    /**
     * Returns a ConnectionProxy.
     *
     * @throws SQLException if an error occurs
     */
    public synchronized Connection getConnection() throws SQLException {
      if(connection!=null){
        throw new SQLException("the PooledConnection is used");
      }else{
        this.connection = new ConnectionProxy(this, _connection);
        return this.connection;
      }
    }

    public synchronized void freeConnection() throws SQLException {
      this.connection=null;
    }
    /**
     * Removes the specified listener from the list.
     *
     * @see #addConnectionEventListener
     * @see #fireConnectionEvent
     */
    public synchronized void removeConnectionEventListener(ConnectionEventListener listener) {
        // Clone the list of listeners to avoid concurrent modifications. See
        // bug [1113040] Small bug in net.sourceforge.jtds.jdbcx.PooledConnection
        // for a description of how these can occur. The method still needs to
        // be synchronized to prevent race conditions.
        listeners = (ArrayList) listeners.clone();
        // Now remove the listener from the new, cloned list
        listeners.remove(listener);
    }
}