cleaned up code and improved error handling

tools.descartes.dml.mm.applicationlevel/src/tools/descartes/dml/mm/applicationlevel/functions/commands/CalculateMeanCommand.java

@@ -18,18 +18,21 @@ public class CalculateMeanCommand extends AbstractHandler {
 	@Override
 	public Object execute(ExecutionEvent event) throws ExecutionException {
 		RandomVariable var = extractRandomVar(event);
-		double d = RandomVariableHelper.getNumericalMean(var.getProbFunction());
-		displayMean(d);
-
+		try {
+			double d = RandomVariableHelper.getNumericalMean(var.getProbFunction());
+			displayString("The mean of the selected RandomVariable is " + d, "Calculate Mean");
+		} catch (Exception e) {
+			displayString(e.getMessage(), "Error");
+		}
 		return null;
 	}
 
-	private void displayMean(double d) {
+	private void displayString(String message, String title) {
 		PlatformUI.getWorkbench().getDisplay().asyncExec(new Runnable() {
 			public void run() {
 				Shell activeShell = PlatformUI.getWorkbench().getActiveWorkbenchWindow().getShell();
-				MessageDialog dialog = new MessageDialog(activeShell, "Calculate Mean", null,
-						"The mean of the selected RandomVariable is " + d, 0, 0, "OK");
+				MessageDialog dialog = new MessageDialog(activeShell, title, null,
+						message, 0, 0, "OK");
 				dialog.open();
 			}
 		});

tools.descartes.dml.mm.applicationlevel/src/tools/descartes/dml/mm/applicationlevel/functions/util/RandomVariableHelper.java

@@ -19,16 +19,41 @@ import tools.descartes.dml.mm.applicationlevel.functions.ProbabilityMassFunction
 import tools.descartes.dml.mm.applicationlevel.functions.SampleList;
 
 /**
- * Provides helper functions for ProbabilityFunctions, e.g., to compute their mean value.
+ * Provides helper functions for ProbabilityFunctions, e.g., to compute their
+ * mean value.
  * 
  * @author Fabian Brosig
  */
 public class RandomVariableHelper {
-	
+
+	/*
+	 * I know it is ugly...but apparently there is no other solution that works
+	 * (With QVTO blackboxes, the probfn parameter seems to be explicitly casted so
+	 * that method overloading does not work as expected.)
+	 */
+	public static Double getNumericalMean(ProbabilityFunction probfn) {
+		if (probfn instanceof IntLiteral)
+			return _getNumericalMean((IntLiteral) probfn);
+		if (probfn instanceof DoubleLiteral)
+			return _getNumericalMean((DoubleLiteral) probfn);
+		if (probfn instanceof BooleanLiteral)
+			return _getNumericalMean((BooleanLiteral) probfn);
+		if (probfn instanceof ExponentialDistribution)
+			return _getNumericalMean((ExponentialDistribution) probfn);
+		if (probfn instanceof NormalDistribution)
+			return _getNumericalMean((NormalDistribution) probfn);
+		if (probfn instanceof BoxedPDF)
+			return _getNumericalMean((BoxedPDF) probfn);
+		if (probfn instanceof ProbabilityMassFunction)
+			return _getNumericalMean((ProbabilityMassFunction) probfn);
+
+		return _getNumericalMean(probfn);
+	}
+
 	private static Double _getNumericalMean(ProbabilityMassFunction pmf) {
 		return RandomVariableHelper._getNumericalMean(pmf.getSamples());
 	}
-	
+
 	private static Double _getNumericalMean(IntSampleList intsl) {
 		int[] singletons = new int[intsl.getItems().size()];
 		double[] probabilities = new double[intsl.getItems().size()];
@@ -39,7 +64,7 @@ public class RandomVariableHelper {
 		EnumeratedIntegerDistribution dist = new EnumeratedIntegerDistribution(singletons, probabilities);
 		return dist.getNumericalMean();
 	}
-	
+
 	private static Double _getNumericalMean(DoubleSampleList doublesl) {
 		double[] singletons = new double[doublesl.getItems().size()];
 		double[] probabilities = new double[doublesl.getItems().size()];
@@ -52,22 +77,25 @@ public class RandomVariableHelper {
 	}
 
 	private static Double _getNumericalMean(SampleList sl) {
-		// I know it is ugly...
-		     if (sl instanceof IntSampleList) return _getNumericalMean( (IntSampleList) sl );
-		else if (sl instanceof BoolSampleList) return _getNumericalMean( (BoolSampleList) sl );
-		else if (sl instanceof DoubleSampleList) return _getNumericalMean( (DoubleSampleList) sl );
-		else if (sl instanceof EnumSampleList) return _getNumericalMean( (EnumSampleList) sl );
-		return null;
+		if (sl instanceof IntSampleList)
+			return _getNumericalMean((IntSampleList) sl);
+		else if (sl instanceof BoolSampleList)
+			return _getNumericalMean((BoolSampleList) sl);
+		else if (sl instanceof DoubleSampleList)
+			return _getNumericalMean((DoubleSampleList) sl);
+		else if (sl instanceof EnumSampleList)
+			return _getNumericalMean((EnumSampleList) sl);
+		throw new IllegalStateException("Unknown type of SampleList: " + sl.getClass().getName());
 	}
-	
+
 	private static Double _getNumericalMean(EnumSampleList enumsl) {
 		throw new UnsupportedOperationException("Enums do not have a numerical mean.");
 	}
-	
+
 	private static Double _getNumericalMean(BoolSampleList enumsl) {
-		return null;
+		throw new UnsupportedOperationException("Booleans do not have a numerical mean.");
 	}
-	
+
 	private static Double _getNumericalMean(BoxedPDF bpdf) {
 		double mean = 0;
 		double lastValue = 0;
@@ -78,47 +106,32 @@ public class RandomVariableHelper {
 
 		return mean;
 	}
-	
+
 	private static Double _getNumericalMean(NormalDistribution nd) {
 		return nd.getMu().doubleValue();
 	}
-	
+
 	private static Double _getNumericalMean(ExponentialDistribution expd) {
-		double rate = expd.getRate().doubleValue(); 
-		return (rate > 0) ? 1/rate : null;
+		double rate = expd.getRate().doubleValue();
+		if (rate > 0)
+			return 1 / rate;
+		throw new UnsupportedOperationException("ExponentialDistribution can not have a rate of 0");
 	}
-	
+
 	private static Double _getNumericalMean(BooleanLiteral l) {
-		return null;
+		throw new UnsupportedOperationException("Booleans do not have a numerical mean.");
 	}
-	
+
 	private static Double _getNumericalMean(DoubleLiteral l) {
 		return l.getValue().doubleValue();
 	}
-	
+
 	private static Double _getNumericalMean(IntLiteral l) {
 		return l.getValue().doubleValue();
 	}
-	
+
 	private static Double _getNumericalMean(ProbabilityFunction probfn) {
-		assert false; // thanks to method overloading, this method should never be invoked
-		return null;
+		throw new IllegalStateException("Unknown type of ProbabilityFunction: " + probfn.getClass().getName());
 	}
-	
-	public static Double getNumericalMean(ProbabilityFunction probfn) {
-		// I know it is ugly...but apparently there is no other solution that works 
-		// (With QVTO blackboxes, the probfn parameter seems to be explicitly casted so that method overloading does not work as expected.)
-			 if (probfn instanceof IntLiteral) return _getNumericalMean( (IntLiteral) probfn );
-		else if (probfn instanceof DoubleLiteral) return _getNumericalMean( (DoubleLiteral) probfn );
-		else if (probfn instanceof BooleanLiteral) return _getNumericalMean( (BooleanLiteral) probfn );
-		else if (probfn instanceof ExponentialDistribution) return _getNumericalMean( (ExponentialDistribution) probfn );
-		else if (probfn instanceof NormalDistribution) return _getNumericalMean( (NormalDistribution) probfn );
-		else if (probfn instanceof BoxedPDF) return _getNumericalMean( (BoxedPDF) probfn );
-		else if (probfn instanceof ProbabilityMassFunction) return _getNumericalMean( (ProbabilityMassFunction) probfn );
-		else if (probfn instanceof ProbabilityMassFunction)
-			return _getNumericalMean((BoxedPDF) probfn);
-		else { return _getNumericalMean(probfn); }	
-	}
-	
-}
 
+}