mysqlresultsetmetadata.java

来自「RESIN 3.2 最新源码」· Java 代码 · 共 102 行

/*
 * Copyright (c) 1998-2008 Caucho Technology -- all rights reserved
 *
 * This file is part of Resin(R) Open Source
 *
 * Each copy or derived work must preserve the copyright notice and this
 * notice unmodified.
 *
 * Resin Open Source is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * Resin Open Source is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE, or any warranty
 * of NON-INFRINGEMENT.  See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Resin Open Source; if not, write to the
 *
 *   Free Software Foundation, Inc.
 *   59 Temple Place, Suite 330
 *   Boston, MA 02111-1307  USA
 *
 * @author Nam Nguyen
 */

package com.caucho.quercus.lib.db;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.util.logging.Logger;

import com.caucho.quercus.QuercusException;
import com.caucho.util.L10N;


/**
 * Extra Mysql metadata.
 * XXX: implement more methods
 */
public class MysqlResultSetMetaData
{
  private static final Logger log
    = Logger.getLogger(MysqlResultSetMetaData.class.getName());
  private static final L10N L
    = new L10N(MysqlResultSetMetaData.class);
  
  private ResultSetMetaData _resultSetMetaData;
  
  private String []_columnEncodings;
  
  protected MysqlResultSetMetaData(ResultSetMetaData metaData)
  {
    _resultSetMetaData = metaData;
    
    try {
      _columnEncodings = new String[metaData.getColumnCount()];
    } catch (SQLException e) {
      throw new QuercusException(e);
    }
  }
  
  public String getColumnCharacterEncoding(int column)
  {
    String encoding = _columnEncodings[column - 1];
    
    if (encoding == null) {
      encoding = getColumnCharacterEncodingImpl(column);
      
      _columnEncodings[column - 1] = encoding;
    }
    
    return encoding;
  }
  
  private String getColumnCharacterEncodingImpl(int column)
  {
    Class cls = _resultSetMetaData.getClass();
    
    try {
      Method method = cls.getMethod("getColumnCharacterEncoding", int.class);
      
      Object result = method.invoke(_resultSetMetaData, column);
      
      return (String) result;
      
    } catch (NoSuchMethodException e) {
      throw new QuercusException(e);
    } catch (InvocationTargetException e) {
      throw new QuercusException(e);
    } catch (IllegalAccessException e) {
      throw new QuercusException(e);
    }
  }

}