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.
   */
  
  /*
   * ClassAssigner.java
   * Copyright (C) 2006 University of Waikato, Hamilton, New Zealand
   */
  
  package weka.filters.unsupervised.attribute;
  
  import weka.core.Capabilities;
  import weka.core.Instance; 
  import weka.core.DenseInstance;
  import weka.core.Instances;
  import weka.core.Option;
  import weka.core.RevisionUtils;
  import weka.core.Utils;
  import weka.core.Capabilities.Capability;
  import weka.filters.SimpleStreamFilter;
  
  import java.util.Enumeration;
  import java.util.Vector;
  
  /**
   <!-- globalinfo-start -->
   * Filter that can set and unset the class index.
   * <p/>
   <!-- globalinfo-end -->
   *
   <!-- options-start -->
   * Valid options are: <p/>
   * 
   * <pre> -D
   *  Turns on output of debugging information.</pre>
   * 
   * <pre> -C &lt;num|first|last|0&gt;
   *  The index of the class attribute. Index starts with 1, 'first'
   *  and 'last' are accepted, '0' unsets the class index.
   *  (default: last)</pre>
   * 
   <!-- options-end -->
   *
   * @author  fracpete (fracpete at waikato dot ac dot nz)
   * @version $Revision: 5987 $
   */
  public class ClassAssigner
    extends SimpleStreamFilter {
  
    /** for serialization. */
    private static final long serialVersionUID = 1775780193887394115L;
  
    /** use the first attribute as class. */
    public final static int FIRST = 0;
    
    /** use the last attribute as class. */
    public final static int LAST = -2;
    
    /** unset the class attribute. */
    public final static int UNSET = -1;
    
    /** the class index. */
    protected int m_ClassIndex = LAST;
    
    /**
     * Returns a string describing this classifier.
     * 
     * @return 		a description of the classifier suitable for
     * 			displaying in the explorer/experimenter gui
     */
    public String globalInfo() {
      return 
          "Filter that can set and unset the class index.";
    }
  
    /**
     * Returns an enumeration describing the available options.
     *
     * @return 		an enumeration of all the available options.
     */
    public Enumeration listOptions() {
      Vector result = new Vector();
      Enumeration enm = super.listOptions();
      while (enm.hasMoreElements())
        result.add(enm.nextElement());
        
      result.addElement(new Option(
  	"\tThe index of the class attribute. Index starts with 1, 'first'\n"
  	+ "\tand 'last' are accepted, '0' unsets the class index.\n"
  	+ "\t(default: last)",
  	"C", 1, "-C <num|first|last|0>"));
  
      return result.elements();
    }
  
    /**
     * Parses a list of options for this object. <p/>
     *
     <!-- options-start -->
     * Valid options are: <p/>
     * 
     * <pre> -D
     *  Turns on output of debugging information.</pre>
     * 
     * <pre> -C &lt;num|first|last|0&gt;
     *  The index of the class attribute. Index starts with 1, 'first'
     *  and 'last' are accepted, '0' unsets the class index.
     *  (default: last)</pre>
     * 
     <!-- options-end -->
     *
     * @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 {
      String        tmpStr;
  
      super.setOptions(options);
      
      tmpStr = Utils.getOption("C", options);
      if (tmpStr.length() != 0)
        setClassIndex(tmpStr);
      else
        setClassIndex("last");
    }
  
    /**
     * Gets the current settings of the filter.
     *
     * @return 		an array of strings suitable for passing to setOptions
     */
    public String[] getOptions() {
      Vector        result;
      String[]      options;
      int           i;
  
      result = new Vector();
  
      options = super.getOptions();
      for (i = 0; i < options.length; i++)
        result.add(options[i]);
  
      result.add("-C");
      result.add(getClassIndex());
  
      return (String[]) result.toArray(new String[result.size()]);
    }
  
    /**
     * Returns the tip text for this property.
     *
     * @return 		tip text for this property suitable for
     * 			displaying in the explorer/experimenter gui
     */
    public String classIndexTipText() {
      return 
          "The index of the class attribute, starts with 1, 'first' and 'last' "
        + "are accepted as well, '0' unsets the class index.";
    }
  
    /**
     * sets the class index.
     * 
     * @param value	the class index
     */
    public void setClassIndex(String value) {
      if (value.equalsIgnoreCase("first")) {
        m_ClassIndex = FIRST;
      }
      else if (value.equalsIgnoreCase("last")) {
        m_ClassIndex = LAST;
      }
      else if (value.equalsIgnoreCase("0")) {
        m_ClassIndex = UNSET;
      }
      else {
        try {
  	m_ClassIndex = Integer.parseInt(value) - 1;
        }
        catch (Exception e) {
  	System.err.println("Error parsing '" + value + "'!");
        }
      }
    }
  
    /**
     * returns the class index.
     * 
     * @return		the class index
     */
    public String getClassIndex() {
      if (m_ClassIndex == FIRST)
        return "first";
      else if (m_ClassIndex == LAST)
        return "last";
      else if (m_ClassIndex == UNSET)
        return "0";
      else
        return "" + (m_ClassIndex + 1);
    }
  
    /** 
     * Returns the Capabilities of this filter.
     *
     * @return            the capabilities of this object
     * @see               Capabilities
     */
    public Capabilities getCapabilities() {
      Capabilities result = super.getCapabilities();
      result.disableAll();
      
      // attributes
      result.enableAllAttributes();
      result.enable(Capability.MISSING_VALUES);
      
      // class
      result.enableAllClasses();
      result.enable(Capability.NO_CLASS);
      result.enable(Capability.MISSING_CLASS_VALUES);
      
      return result;
    }
  
    /**
     * Determines the output format based on the input format and returns 
     * this.
     *
     * @param inputFormat     the input format to base the output format on
     * @return                the output format
     * @throws Exception      in case the class index is invalid
     */
    protected Instances determineOutputFormat(Instances inputFormat)
        throws Exception {
      
      Instances result = new Instances(inputFormat, 0);
      
      if (m_ClassIndex == FIRST)
        result.setClassIndex(0);
      else if (m_ClassIndex == LAST)
        result.setClassIndex(result.numAttributes() - 1);
      else if (m_ClassIndex == UNSET)
        result.setClassIndex(-1);
      else
        result.setClassIndex(m_ClassIndex);
      
      return result;
    }
  
    /**
     * processes the given instance (may change the provided instance) and
     * returns the modified version.
     *
     * @param instance    the instance to process
     * @return            the modified data
     * @throws Exception  in case the processing goes wrong
     */
    protected Instance process(Instance instance) throws Exception {
      return instance;
    }
    
    /**
     * Returns the revision string.
     * 
     * @return		the revision
     */
    public String getRevision() {
      return RevisionUtils.extract("$Revision: 5987 $");
    }
  
    /**
     * Main method for executing this class.
     *
     * @param args should contain arguments for the filter: use -h for help
     */
    public static void main(String[] args) {
      runFilter(new ClassAssigner(), args);
    }
  }
  