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.
   */
  
  /*
   *    NormDiscrete.java
   *    Copyright (C) 2008 University of Waikato, Hamilton, New Zealand
   *
   */
  
  package weka.core.pmml;
  
  import java.util.ArrayList;
  
  import org.w3c.dom.Element;
  
  import weka.core.Attribute;
  import weka.core.Instance;
  import weka.core.Utils;
  
  /**
   * Class encapsulating a NormDiscrete Expression. Creates an
   * indicator for a particular discrete value.
   * 
   * @author Mark Hall (mhall{[at]}pentaho{[dot]}com)
   * @version $Revision 1.0 $
   */
  public class NormDiscrete extends Expression {
    
    /**
     * For serialization 
     */
    private static final long serialVersionUID = -8854409417983908220L;
  
    /** The name of the field to lookup our value in */
    protected String m_fieldName;
    
    /** The actual attribute itself */
    protected Attribute m_field;
    
    /** The index of the attribute */
    protected int m_fieldIndex = -1;
    
    /** The actual value (as a String) that will correspond to an output of 1 */
    protected String m_fieldValue;
    
    /** True if a replacement for missing values has been specified */
    protected boolean m_mapMissingDefined = false;
    
    /** The value of the missing value replacement (if defined) */
    protected double m_mapMissingTo;
    
    /**
     *  If we are referring to a nominal (rather than String) attribute
     * then this holds the index of the value in question. Will be faster
     * than searching for the value each time.
     */
    protected int m_fieldValueIndex = -1;
    
    /**
     * Constructor. Reads the field name and field value for this NormDiscrete
     * Expression.
     * 
     * @param normDisc the Element encapsulating this NormDiscrete
     * @param opType the optype for this expression (taken from either the
     * enclosing DefineFunction or DerivedField)
     * @param fieldDefs an ArrayList of Attributes for the fields that this
     * Expression might need to access
     * enclosing DefineFunction or DerivedField)
     * @throws Exception if there is a problem parsing this Apply Expression
     */
    public NormDiscrete(Element normDisc, FieldMetaInfo.Optype opType, ArrayList<Attribute> fieldDefs)
      throws Exception {
      super(opType, fieldDefs);
      
      if (opType != FieldMetaInfo.Optype.CONTINUOUS) {
        throw new Exception("[NormDiscrete] can only have a continuous optype");
      }
      
      m_fieldName = normDisc.getAttribute("field");
      m_fieldValue = normDisc.getAttribute("value");
      
      String mapMissing = normDisc.getAttribute("mapMissingTo");
      if (mapMissing != null && mapMissing.length() > 0) {
        m_mapMissingTo = Double.parseDouble(mapMissing);
        m_mapMissingDefined = true;
      }
      
      if (fieldDefs != null) {
        setUpField();
      }
    }
    
    /**
     * Set the field definitions for this Expression to use
     * 
     * @param fieldDefs the field definitions to use
     * @throws Exception if there is a problem setting the field definitions
     */
    public void setFieldDefs(ArrayList<Attribute> fieldDefs) throws Exception {
      super.setFieldDefs(fieldDefs);
      setUpField();
    }
    
    /**
     * Find the named field, set up the index(es) etc.
     * 
     * @throws Exception if a problem occurs.
     */
    private void setUpField() throws Exception {
      m_fieldIndex = -1;
      m_fieldValueIndex = -1;
      m_field = null;
      
      if (m_fieldDefs != null) {
        m_fieldIndex = getFieldDefIndex(m_fieldName);
  
        if (m_fieldIndex < 0) {
          throw new Exception("[NormDiscrete] Can't find field " + m_fieldName
              + " in the supplied field definitions.");
        }
        m_field = m_fieldDefs.get(m_fieldIndex);
        
        if (!(m_field.isString() || m_field.isNominal())) {
          throw new Exception("[NormDiscrete] reference field " + m_fieldName
              +" must be categorical");
        }
        
        if (m_field.isNominal()) {
          // set up the value index
          m_fieldValueIndex = m_field.indexOfValue(m_fieldValue);
          if (m_fieldValueIndex < 0) {
            throw new Exception("[NormDiscrete] Unable to find value " + m_fieldValue
                + " in nominal attribute " + m_field.name());
          }
        } else if (m_field.isString()) {
          // add our value to this attribute (if it is already there
          // then this will have no effect).
          m_fieldValueIndex = m_field.addStringValue(m_fieldValue);
        }
      }
    }
  
    /**
     * Return the structure of the result of applying this Expression
     * as an Attribute.
     * 
     * @return the structure of the result of applying this Expression as an
     * Attribute.
     */
    protected Attribute getOutputDef() {    
      return new Attribute(m_fieldName + "=" + m_fieldValue);
    }
  
    /**
     * Get the result of evaluating the expression. In the case
     * of a continuous optype, a real number is returned; in
     * the case of a categorical/ordinal optype, the index of the nominal
     * value is returned as a double.
     * 
     * @param incoming the incoming parameter values
     * @return the result of evaluating the expression
     * @throws Exception if there is a problem computing the result
     */
    public double getResult(double[] incoming) throws Exception {
      
      double result = 0.0;
      if (Utils.isMissingValue(incoming[m_fieldIndex])) {
        if (m_mapMissingDefined) {
          result = m_mapMissingTo; // return the replacement
        } else {
          result = incoming[m_fieldIndex]; // just return the missing value
        }
      } else {
        if (m_fieldValueIndex == (int)incoming[m_fieldIndex]) {
          result = 1.0;
        }
      }
      
      return result;
    }
  
    /**
     * Always throws an Exception since the result of NormDiscrete must
     * be continuous.
     * 
     * @param incoming the incoming parameter values
     * @throws Exception always
     */
    public String getResultCategorical(double[] incoming) throws Exception {
      throw new Exception("[NormDiscrete] Can't return the result as a categorical value!");
    }
    
    public String toString(String pad) {
      StringBuffer buff = new StringBuffer();
      buff.append("NormDiscrete: " + m_fieldName + "=" + m_fieldValue);
      if (m_mapMissingDefined) {
        buff.append("\n" + pad + "map missing values to: " + m_mapMissingTo);
      }
      
      return buff.toString();
    }
  }
  