package org.lcsim.geometry.field;
   
   import hep.physics.vec.BasicHep3Vector;
   import hep.physics.vec.Hep3Vector;
   import org.jdom.Element;
   import org.lcsim.geometry.FieldMap;
   import org.lcsim.geometry.compact.Field;
   
   /**
   * Base class for field map implementations. Subclasses should override
   * getXField, getYField, getZField as appropriate (the default implementation
   * returns 0).
   * @author tonyj
   */
  abstract class AbstractFieldMap extends Field implements FieldMap
  {
     AbstractFieldMap(Element node)
     {
        super(node);
     }
     abstract void getField(double x, double y, double z, BasicHep3Vector field);
     
     public Hep3Vector getField(Hep3Vector position, BasicHep3Vector field)
     {
        if (field == null) field = new BasicHep3Vector();
        getField(position.x(),position.y(),position.z(),field);
        return field;
     }
     
     public Hep3Vector getField(Hep3Vector position)
     {
        return getField(position,null);
     }
     
     public void getField(double[] position, double[] b)
     {
        BasicHep3Vector field = new BasicHep3Vector();
        getField(position[0],position[1],position[2],field);
        b[0] = field.x();
        b[1] = field.y();
        b[2] = field.z();
     }
     
     public double[] getField(double[] position)
     {
        BasicHep3Vector field = new BasicHep3Vector();
        getField(position[0],position[1],position[2],field);
        return field.v();
     }
  }