content: /*
   *    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.
   */
  
  /*
   *    AttributeTransformer.java
   *    Copyright (C) 2000 University of Waikato, Hamilton, New Zealand
   *
   */
  
  package weka.attributeSelection;
  
  import weka.core.Instance;
  import weka.core.Instances;
  
  /** 
   * Abstract attribute transformer. Transforms the dataset.
   *
   * @author Mark Hall (mhall@cs.waikato.ac.nz)
   * @version $Revision: 4613 $
   */
  public interface AttributeTransformer {
      // ===============
      // Public methods.
      // ===============
  
    /**
     * Returns just the header for the transformed data (ie. an empty
     * set of instances. This is so that AttributeSelection can
     * determine the structure of the transformed data without actually
     * having to get all the transformed data through getTransformedData().
     * @return the header of the transformed data.
     * @exception Exception if the header of the transformed data can't
     * be determined.
     */
    Instances transformedHeader() throws Exception;
  
    /**
     * Transform the supplied data set (assumed to be the same format
     * as the training data)
     * @return A set of instances representing the transformed data
     * @exception Exception if the attribute could not be evaluated
     */
    Instances transformedData(Instances data) throws Exception;
  
    /**
     * Transforms an instance in the format of the original data to the
     * transformed space
     * @return a transformed instance
     * @exception Exception if the instance could not be transformed
     */
    Instance convertInstance(Instance instance) throws Exception;
  }
  