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.
   */
  
  /*
   *    PotentialClassIgnorer.java
   *    Copyright (C) 2003 University of Waikato, Hamilton, New Zealand
   *
   */
  
  package weka.filters.unsupervised.attribute;
  
  import weka.core.Instances;
  import weka.core.Option;
  import weka.core.OptionHandler;
  import weka.core.Utils;
  import weka.filters.Filter;
  
  import java.util.Enumeration;
  import java.util.Vector;
  
  /**
   * This filter should be extended by other unsupervised attribute
   * filters to allow processing of the class attribute if that's
   * required. It the class is to be ignored it is essential that the
   * extending filter does not change the position (i.e. index) of the
   * attribute that is originally the class attribute !
   *
   * @author Eibe Frank (eibe@cs.waikato.ac.nz), Mark Hall (mhall@cs.waikato.ac.nz)
   * @version $Revision: 1.7 $ 
   */
  public abstract class PotentialClassIgnorer
    extends Filter
    implements OptionHandler {
  
    /** for serialization */
    private static final long serialVersionUID = 8625371119276845454L;
  
    /** True if the class is to be unset */
    protected boolean m_IgnoreClass = false;
  
    /** Storing the class index */
    protected int m_ClassIndex = -1;
  
    /**
     * Returns an enumeration describing the available options.
     *
     * @return 		an enumeration of all the available options.
     */
    public Enumeration listOptions() {
      Vector result = new Vector();
        
      result.addElement(new Option(
  	"\tUnsets the class index temporarily before the filter is\n"
  	+ "\tapplied to the data.\n"
  	+ "\t(default: no)",
  	"unset-class-temporarily", 1, "-unset-class-temporarily"));
  
      return result.elements();
    }
  
    /**
     * Parses a list of options for this object.
     *
     * @param options 	the list of options as an array of strings
     * @throws Exception 	if an option is not supported
     */
    public void setOptions(String[] options) throws Exception {
      setIgnoreClass(Utils.getFlag("unset-class-temporarily", options));
    }
  
    /**
     * Gets the current settings of the filter.
     *
     * @return 		an array of strings suitable for passing to setOptions
     */
    public String[] getOptions() {
      Vector        result;
  
      result = new Vector();
  
      if (getIgnoreClass())
        result.add("-unset-class-temporarily");
  
      return (String[]) result.toArray(new String[result.size()]);
    }
  
    /**
     * Sets the format of the input instances. If the filter is able to
     * determine the output format before seeing any input instances, it
     * does so here. This default implementation clears the output format
     * and output queue, and the new batch flag is set. Overriders should
     * call <code>super.setInputFormat(Instances)</code>
     *
     * @param instanceInfo an Instances object containing the input instance
     * structure (any instances contained in the object are ignored - only the
     * structure is required).
     * @return true if the outputFormat may be collected immediately
     * @throws Exception if the inputFormat can't be set successfully 
     */
    public boolean setInputFormat(Instances instanceInfo) throws Exception {
  
      boolean result = super.setInputFormat(instanceInfo);
      if (m_IgnoreClass) {
        m_ClassIndex = inputFormatPeek().classIndex();
        inputFormatPeek().setClassIndex(-1);
      }      
      return result;
    }
  
    /**
     * Gets the format of the output instances. This should only be called
     * after input() or batchFinished() has returned true. The relation
     * name of the output instances should be changed to reflect the
     * action of the filter (eg: add the filter name and options).
     *
     * @return an Instances object containing the output instance
     * structure only.
     * @throws NullPointerException if no input structure has been
     * defined (or the output format hasn't been determined yet) 
     */
    public Instances getOutputFormat() {
  
      if (m_IgnoreClass) {
        outputFormatPeek().setClassIndex(m_ClassIndex);
      }
      return super.getOutputFormat();
    }
  
    /**
     * Returns the tip text for this property
     *
     * @return 		tip text for this property suitable for
     * 			displaying in the explorer/experimenter gui
     */
    public String ignoreClassTipText() {
      return "The class index will be unset temporarily before the filter is applied.";
    }
  
    /**
     * Set the IgnoreClass value. Set this to true if the
     * class index is to be unset before the filter is applied.
     * 
     * @param newIgnoreClass The new IgnoreClass value.
     */
    public void setIgnoreClass(boolean newIgnoreClass) {
      m_IgnoreClass = newIgnoreClass;
    }
    
    /**
     * Gets the IgnoreClass value. If this to true then the
     * class index is to unset before the filter is applied.
     * 
     * @return the current IgnoreClass value.
     */
    public boolean getIgnoreClass() {
      return m_IgnoreClass;
    }
  }
  