made the model events a simple enum.

src/main/java/de/neemann/digital/core/ModelEvent.java

@@ -1,27 +1,43 @@
 package de.neemann.digital.core;
 
 /**
+ * A event fired by the model
+ *
  * @author hneemann
  */
-public class ModelEvent {
+public enum ModelEvent {
 
-    public static final ModelEvent STEP = new ModelEvent(Event.STEP);
+    /**
-    public static final ModelEvent MICROSTEP = new ModelEvent(Event.MICROSTEP);
+     * Is fired after the model had became stable after first stabilization.
-    public static final ModelEvent STARTED = new ModelEvent(Event.STARTED);
+     */
-    public static final ModelEvent BREAK = new ModelEvent(Event.BREAK);
+    STARTED,
-    public static final ModelEvent STOPPED = new ModelEvent(Event.STOPPED);
-    public static final ModelEvent MANUALCHANGE = new ModelEvent(Event.MANUALCHANGE);
 
-    public enum Event {STARTED, STOPPED, STEP, BREAK, MANUALCHANGE, MICROSTEP}
+    /**
+     * The model had stopped.
+     */
+    STOPPED,
 
-    private final Event event;
+    /**
+     * Is fired if the model had performed a full step.
+     * This means a change is propagated through all nodes, and the model has
+     * become stable again.
+     */
+    STEP,
 
-    private ModelEvent(Event event) {
+    /**
-        this.event = event;
+     * A break is detected.
-    }
+     */
+    BREAK,
 
-    public Event getType() {
+    /**
-        return event;
+     * Here was a manual change to the model by the user.
-    }
+     */
+    MANUALCHANGE,
+
+    /**
+     * If fired if a micro step is calculated.
+     * This means the aktual nodes are calculated, but not the effected nodes.
+     */
+    MICROSTEP;
 
 }

src/main/java/de/neemann/digital/core/ModelStateObserver.java

@@ -1,10 +1,17 @@
 package de.neemann.digital.core;
 
 /**
+ * Interface to implement observers of the model.
+ *
  * @author hneemann
  */
 public interface ModelStateObserver {
 
+    /**
+     * called if a event was detected.
+     *
+     * @param event the event
+     */
     void handleEvent(ModelEvent event);
 
 }

src/main/java/de/neemann/digital/draw/model/RealTimeClock.java

@@ -41,7 +41,7 @@ public class RealTimeClock implements ModelStateObserver {
 
     @Override
     public void handleEvent(ModelEvent event) {
-        switch (event.getType()) {
+        switch (event) {
             case STARTED:
                 if (frequency > 50)  // if frequency is high it is not necessary to update the GUI at every clock
                     output.removeObserver(GuiModelObserver.class);

src/main/java/de/neemann/digital/draw/shapes/DataShape.java

@@ -23,14 +23,14 @@ import java.util.ArrayList;
  */
 public class DataShape implements Shape {
 
-    private final ModelEvent.Event type;
+    private final ModelEvent type;
     private DataSet dataSet;
 
     public DataShape(ElementAttributes attr) {
         if (attr.get(AttributeKey.MicroStep))
-            type = ModelEvent.Event.MICROSTEP;
+            type = ModelEvent.MICROSTEP;
         else
-            type = ModelEvent.Event.STEP;
+            type = ModelEvent.STEP;
     }
 
     @Override

src/main/java/de/neemann/digital/gui/GuiModelObserver.java

@@ -16,7 +16,7 @@ import de.neemann.digital.gui.components.CircuitComponent;
  */
 public class GuiModelObserver implements Observer, ModelStateObserver {
     private final CircuitComponent component;
-    private final ModelEvent.Event type;
+    private final ModelEvent type;
     private boolean changed = false;
 
     /**
@@ -25,7 +25,7 @@ public class GuiModelObserver implements Observer, ModelStateObserver {
      * @param component the component to update
      * @param type      the event type which triggers a repainting
      */
-    public GuiModelObserver(CircuitComponent component, ModelEvent.Event type) {
+    public GuiModelObserver(CircuitComponent component, ModelEvent type) {
         this.component = component;
         this.type = type;
     }
@@ -37,7 +37,7 @@ public class GuiModelObserver implements Observer, ModelStateObserver {
 
     @Override
     public void handleEvent(ModelEvent event) {
-        if (changed && event.getType() == type) {
+        if (changed && event == type) {
             component.paintImmediately(0, 0, component.getWidth(), component.getHeight());
             changed = false;
         }

src/main/java/de/neemann/digital/gui/Main.java

@@ -374,7 +374,7 @@ public class Main extends JFrame implements ClosingWindowListener.ConfirmSave, E
             @Override
             public void enter() {
                 super.enter();
-                if (createAndStartModel(settings.get(AttributeKey.StartTimer), ModelEvent.Event.STEP))
+                if (createAndStartModel(settings.get(AttributeKey.StartTimer), ModelEvent.STEP))
                     circuitComponent.setManualChangeObserver(new FullStepObserver(model));
             }
         });
@@ -382,7 +382,7 @@ public class Main extends JFrame implements ClosingWindowListener.ConfirmSave, E
             @Override
             public void enter() {
                 super.enter();
-                if (createAndStartModel(false, ModelEvent.Event.MICROSTEP))
+                if (createAndStartModel(false, ModelEvent.MICROSTEP))
                     circuitComponent.setManualChangeObserver(new MicroStepObserver(model));
             }
         });
@@ -416,7 +416,7 @@ public class Main extends JFrame implements ClosingWindowListener.ConfirmSave, E
     }
 
 
-    private boolean createAndStartModel(boolean runClock, ModelEvent.Event updateEvent) {
+    private boolean createAndStartModel(boolean runClock, ModelEvent updateEvent) {
         try {
             circuitComponent.removeHighLighted();
             circuitComponent.setModeAndReset(true);

src/main/java/de/neemann/digital/gui/components/ProbeDialog.java

@@ -20,10 +20,10 @@ import java.util.List;
  */
 public class ProbeDialog extends JDialog implements ModelStateObserver {
 
-    private final ModelEvent.Event type;
+    private final ModelEvent type;
     private final SignalTableModel tableModel;
 
-    public ProbeDialog(Frame owner, Model model, ModelEvent.Event type, List<String> ordering) {
+    public ProbeDialog(Frame owner, Model model, ModelEvent type, List<String> ordering) {
         super(owner, Lang.get("win_measures"), false);
         setDefaultCloseOperation(DISPOSE_ON_CLOSE);
         this.type = type;
@@ -61,7 +61,7 @@ public class ProbeDialog extends JDialog implements ModelStateObserver {
 
     @Override
     public void handleEvent(ModelEvent event) {
-        if (event.getType() == type || event.getType() == ModelEvent.Event.MANUALCHANGE) {
+        if (event == type || event == ModelEvent.MANUALCHANGE) {
             tableModel.fireChanged();
         }
     }

src/main/java/de/neemann/digital/gui/components/data/DataSetDialog.java

@@ -32,7 +32,7 @@ public class DataSetDialog extends JDialog implements ModelStateObserver {
      * @param type     the event type which triggers a new DataSample
      * @param ordering
      */
-    public DataSetDialog(Frame owner, Model model, ModelEvent.Event type, List<String> ordering) {
+    public DataSetDialog(Frame owner, Model model, ModelEvent type, List<String> ordering) {
         super(owner, Lang.get("win_measures"), false);
         setDefaultCloseOperation(DISPOSE_ON_CLOSE);
         setAlwaysOnTop(true);

src/main/java/de/neemann/digital/gui/components/data/DataSetObserver.java

@@ -9,29 +9,29 @@ import de.neemann.digital.core.ModelStateObserver;
 public class DataSetObserver implements ModelStateObserver {
 
     private final DataSet dataSet;
-    private final ModelEvent.Event type;
+    private final ModelEvent type;
 
     private DataSample manualSample;
     private int maintime;
 
-    public DataSetObserver(ModelEvent.Event type, DataSet dataSet) {
+    public DataSetObserver(ModelEvent type, DataSet dataSet) {
         this.type = type;
         this.dataSet = dataSet;
     }
 
     @Override
     public void handleEvent(ModelEvent event) {
-        if (event.getType() == ModelEvent.Event.STARTED) {
+        if (event == ModelEvent.STARTED) {
             dataSet.clear();
             maintime = 0;
         }
-        if (event.getType() == ModelEvent.Event.MANUALCHANGE) {
+        if (event == ModelEvent.MANUALCHANGE) {
             if (manualSample == null)
                 manualSample = new DataSample(maintime, dataSet.signalSize());
             manualSample.fillWith(dataSet.getSignals());
         }
 
-        if (event.getType() == type) {
+        if (event == type) {
             if (manualSample != null) {
                 dataSet.add(manualSample);
                 manualSample = null;