git.gag.com Git - debian/openrocket/blob - core/src/net/sf/openrocket/simulation/customexpression/IndexExpression.java

   1 package net.sf.openrocket.simulation.customexpression;
   2
   3 import java.util.List;
   4
   5 import de.congrace.exp4j.Calculable;
   6 import de.congrace.exp4j.Variable;
   7 import net.sf.openrocket.document.OpenRocketDocument;
   8 import net.sf.openrocket.logging.LogHelper;
   9 import net.sf.openrocket.simulation.customexpression.CustomExpression;
  10 import net.sf.openrocket.simulation.FlightDataType;
  11 import net.sf.openrocket.simulation.SimulationStatus;
  12 import net.sf.openrocket.startup.Application;
  13 import net.sf.openrocket.util.LinearInterpolator;
  14
  15 public class IndexExpression extends CustomExpression {
  16
  17         FlightDataType type;
  18         private static final LogHelper log = Application.getLogger();
  19
  20         public IndexExpression(OpenRocketDocument doc, String indexText, String typeText){
  21                 super(doc);
  22
  23                 setExpression(indexText);
  24                 this.setName("");
  25                 this.setSymbol(typeText);
  26         }
  27
  28         @Override
  29         public Variable evaluate(SimulationStatus status){
  30
  31                 Calculable calc = buildExpression();
  32                 if (calc == null){
  33                         return new Variable("Unknown");
  34                 }
  35
  36                 // From the given datatype, get the time and function values and make an interpolator
  37
  38                 //Note: must get in a way that flight data system will figure out units. Otherwise there will be a type conflict when we get the new data.
  39                 FlightDataType type = FlightDataType.getType(null, getSymbol(), null);
  40
  41                 List<Double> data = status.getFlightData().get(type);
  42                 List<Double> time = status.getFlightData().get(FlightDataType.TYPE_TIME);
  43                 LinearInterpolator interp = new LinearInterpolator(time, data);
  44
  45                 // Evaluate this expression to get the t value
  46                 try{
  47                         double tvalue = calc.calculate().getDoubleValue();
  48                         return new Variable(hash(), interp.getValue( tvalue ) );
  49                 }
  50                 catch (java.util.EmptyStackException e){
  51                         log.user("Unable to calculate time index for indexed expression "+getExpressionString()+" due to empty stack exception");
  52                         return new Variable("Unknown");
  53                 }
  54
  55         }
  56 }