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.
   */
  
  /*
   *    DerivedFieldMetaInfo.java
   *    Copyright (C) 2008 University of Waikato, Hamilton, New Zealand
   *
   */
  
  package weka.core.pmml;
  
  import java.io.Serializable;
  import java.util.ArrayList;
  
  import org.w3c.dom.Element;
  import org.w3c.dom.Node;
  import org.w3c.dom.NodeList;
  
  import weka.core.Attribute;
  import weka.core.Instances;
  
  public class DerivedFieldMetaInfo extends FieldMetaInfo implements Serializable {
    
    /** for serialization */
    
    /** display name */
    protected String m_displayName = null;
    
    /** 
     * the list of values (if the field is ordinal) - may be of size zero if none are specified.
     * If none are specified, we may be able to construct this by querying the Expression in
     * this derived field 
     */
    protected ArrayList<Value> m_values = new ArrayList<Value>();
    
    /** the single expression that defines the value of this field */
    protected Expression m_expression;
    
    public DerivedFieldMetaInfo(Element derivedField, ArrayList<Attribute> fieldDefs,
                                TransformationDictionary transDict) throws Exception {
      super(derivedField);
      // m_fieldName = derivedField.getAttribute("name");
      String displayName = derivedField.getAttribute("displayName");
      if (displayName != null && displayName.length() > 0) {
        m_displayName = displayName;
      }
      
      // get any values
      NodeList valL = derivedField.getElementsByTagName("Value");
      if (valL.getLength() > 0) {
        for (int i = 0; i < valL.getLength(); i++) {
          Node valueN = valL.item(i);
          if (valueN.getNodeType() == Node.ELEMENT_NODE) {
            Value v = new Value((Element)valueN);
            m_values.add(v);
          }
        }
      }
      
      // now get the expression
      m_expression = Expression.getExpression(derivedField, m_optype, fieldDefs, transDict);
    }
    
    /**
     * Upadate the field definitions for this derived field
     * 
     * @param fieldDefs the fields as an ArrayList of Attributes
     * @throws Exception if there is a problem setting the field definitions
     */
    public void setFieldDefs(ArrayList<Attribute> fieldDefs) throws Exception {
      m_expression.setFieldDefs(fieldDefs);
    }
    
    /**
     * Upadate the field definitions for this derived field
     * 
     * @param fields the fields as an Instances object
     * @throws Exception if there is a problem setting the field definitions
     */
    public void setFieldDefs(Instances fields) throws Exception {
      ArrayList<Attribute> tempDefs = new ArrayList<Attribute>();
      for (int i = 0; i < fields.numAttributes(); i++) {
        tempDefs.add(fields.attribute(i));
      }
      setFieldDefs(tempDefs);
    }
    
    /**
     * Get this derived field as an Attribute.
     * 
     * @return an Attribute for this derived field.
     */
    public Attribute getFieldAsAttribute() {
      return m_expression.getOutputDef().copy(m_fieldName);
    }
    
    /**
     * Get the derived field value for the given incoming vector of
     * values. Incoming values are assumed to be in the same order
     * as the attributes supplied in the field definitions ArrayList
     * used to construct this DerivedField.
     * 
     * If the optype of this derived field is continuous, then a real
     * number is returned. Otherwise, the number returned is the index
     * of the categorical/ordinal value corresponding to result of computing
     * the derived field value.
     * 
     * @param incoming the incoming parameter values
     * @return the result of computing the derived value
     * @throws Exception if there is a problem computing the value
     */
    public double getDerivedValue(double[] incoming) throws Exception {
      return m_expression.getResult(incoming);
    }
    
    public String toString() {
      StringBuffer buff = new StringBuffer();
      buff.append(getFieldAsAttribute() + "\nexpression:\n");
      buff.append(m_expression + "\n");
      
      return buff.toString();
    }
  }
  