columninfo.java

一个数据挖掘软件ALPHAMINERR的整个过程的JAVA版源代码

/*
 *    This program 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.
 *
 *    This program 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.  See the
 *    GNU General Public License for more details.
 *
 *    You should have received a copy of the GNU General Public License
 *    along with this program; if not, write to the Free Software
 *    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

 /**
  * Title: XELOPES Data Mining Library
  * Description: The XELOPES library is an open platform-independent and data-source-independent library for Embedded Data Mining.
  * Copyright: Copyright (c) 2002 Prudential Systems Software GmbH
  * Company: ZSoft (www.zsoft.ru), Prudsys (www.prudsys.com)
  * @author Valentine Stepanenko ([e-mail])
  * @version 1.0
  */

package com.prudsys.pdm.Input.Relational;

/**
 * Base class for column description.
 */
public class ColumnInfo
{
  protected String name;
  protected String remarks;
  protected boolean nullable;

  /**
   * Constructor of column info from given result set of column.
   *
   * @param rs given result set of column
   * @throws java.sql.SQLException cannot read result set
   */
  ColumnInfo(java.sql.ResultSet rs) throws java.sql.SQLException {
    name = rs.getString("COLUMN_NAME");
    remarks = rs.getString("REMARKS");
    int nl = rs.getInt("NULLABLE");
    if(nl == java.sql.DatabaseMetaData.columnNullable) nullable = true;
    else nullable = false;
  }

  /**
   * Returns column name.
   *
   * @return column name
   */
  public String getName() {
    return name;
  }

  /**
   * Returns remarks of column.
   *
   * @return column remark
   */
  public String getRemarks() {
    return remarks;
  }

  /**
   * Allows empty values.
   *
   * @return allows empty values
   */
  public boolean isNullable() {
    return nullable;
  }

  /**
   * Returns string representation of column info
   *
   * @return string representation of column info
   */
  public String toString() {
    return name;
  }

  /**
   * Constructs column info from given result set.
   *
   * @param rs result set for obtaining column info
   * @return column info obtained from given result set
   * @throws java.sql.SQLException cannot obtain column info
   */
  public static ColumnInfo getColumnInfo(java.sql.ResultSet rs) throws java.sql.SQLException {

    ColumnInfo ci = null;
    short type = rs.getShort("DATA_TYPE");
    //System.out.println(type);
    if(type == java.sql.Types.BIGINT||
       type == java.sql.Types.DECIMAL||
       type == java.sql.Types.DOUBLE||
       type == java.sql.Types.FLOAT||
       type == java.sql.Types.INTEGER||
       type == java.sql.Types.NUMERIC||
       type == java.sql.Types.REAL||
       type == java.sql.Types.SMALLINT||
       type == java.sql.Types.TINYINT
       )
    ci = new NumericColumn(rs);
    else if(type == java.sql.Types.CHAR||
            type == java.sql.Types.VARCHAR)
    ci = new StringColumn(rs);
    return ci;
  }
}