Master Thesis - SCChart Edge Merge - Code Review

plugins/de.cau.cs.kieler.sccharts.ui/META-INF/services/de.cau.cs.kieler.sccharts.ui.synthesis.hooks.SynthesisHook

@@ -1,4 +1,5 @@
 de.cau.cs.kieler.sccharts.ui.synthesis.hooks.DeclarationsHook
+de.cau.cs.kieler.sccharts.ui.synthesis.hooks.EdgeMergeHook
 de.cau.cs.kieler.sccharts.ui.synthesis.hooks.LocalDeclarationsHook
 de.cau.cs.kieler.sccharts.ui.synthesis.hooks.StateActionsHook
 de.cau.cs.kieler.sccharts.ui.synthesis.hooks.BlackWhiteModeHook

plugins/de.cau.cs.kieler.sccharts.ui/src/de/cau/cs/kieler/sccharts/ui/synthesis/TransitionSynthesis.xtend

@@ -51,7 +51,7 @@ import static extension de.cau.cs.kieler.klighd.syntheses.DiagramSyntheses.*
 class TransitionSynthesis extends SubSynthesis<Transition, KEdge> {
 
     /**
-     * Immediate transition will be more likely drwn from left to right as long as there are no more than this threshold
+     * Immediate transition will be more likely drawn from left to right as long as there are no more than this threshold
      *  number of other edges to flip to break a cycle.
      */ 
     public static val IMMEDIATE_TRANSITION_DIRECTION_THRESHOLD = 6

plugins/de.cau.cs.kieler.sccharts.ui/src/de/cau/cs/kieler/sccharts/ui/synthesis/hooks/EdgeMergeHook.xtend

@@ -0,0 +1,115 @@
+/*
+ * KIELER - Kiel Integrated Environment for Layout Eclipse RichClient
+ * 
+ * http://www.informatik.uni-kiel.de/rtsys/kieler/
+ * 
+ * Copyright 2021,2022 by
+ * + Kiel University
+ *   + Department of Computer Science
+ *     + Real-Time and Embedded Systems Group
+ * 
+ * This code is provided under the terms of the Eclipse Public License (EPL).
+ * See the file epl-v10.html for the license text.
+ */
+package de.cau.cs.kieler.sccharts.ui.synthesis.hooks
+
+import de.cau.cs.kieler.klighd.krendering.ViewSynthesisShared
+import de.cau.cs.kieler.sccharts.ui.synthesis.hooks.SynthesisHook
+import de.cau.cs.kieler.klighd.kgraph.KNode
+import de.cau.cs.kieler.sccharts.State
+import de.cau.cs.kieler.klighd.kgraph.KEdge
+import de.cau.cs.kieler.sccharts.Transition
+import de.cau.cs.kieler.sccharts.Scope
+import org.eclipse.xtend.lib.annotations.Data
+import de.cau.cs.kieler.sccharts.PreemptionType
+import de.cau.cs.kieler.sccharts.HistoryType
+import de.cau.cs.kieler.sccharts.DeferredType
+import java.util.HashMap
+import de.cau.cs.kieler.sccharts.ui.synthesis.GeneralSynthesisOptions
+import de.cau.cs.kieler.klighd.SynthesisOption
+import de.cau.cs.kieler.sccharts.DelayType
+
+/**
+ * Merge transitions that are considered semantically similar to be visualized using one edge.
+ */
+@ViewSynthesisShared
+class EdgeMergeHook extends SynthesisHook {
+
+
+    /** The related synthesis option */
+    public static final SynthesisOption MERGE_SIMILAR_EDGES = SynthesisOption.createCheckOption(EdgeMergeHook, "Merge Similar Edges",
+            false).setCategory(GeneralSynthesisOptions::APPEARANCE);
+
+    override getDisplayedSynthesisOptions() {
+        return newLinkedList(de.cau.cs.kieler.sccharts.ui.synthesis.hooks.EdgeMergeHook.MERGE_SIMILAR_EDGES)
+    }
+
+    /**
+     * a mapping of an edge group key to the representative edge for that group
+     */
+    HashMap<EdgeGroupKey, KEdge> map = new HashMap<EdgeGroupKey,KEdge>();
+
+    /**
+     * A Key used to determine if two transitions are semantically similar to be represented by one edge
+     */
+    @Data
+    static class EdgeGroupKey {
+        State source;
+        State target;
+        PreemptionType preemption;
+        HistoryType history;
+        DeferredType deferred;
+        DelayType delay;
+        boolean deterministic;
+    }
+
+    /** 
+     * Invoked before the translation of the model starts.
+     * @param scopethe input model
+     * @param nodethe empty diagram root node
+     */
+    override void start(Scope scope, KNode node) {
+        // reset the map of representative edges as we start a new synthesis
+        map.clear()
+    }
+
+    /** 
+     * Invoked after a {@link Transition} is translated.
+     * @param transitionthe transition
+     * @param edgethe translated edge
+     */
+    override void processTransition(Transition transition, KEdge edge) {
+
+        if (MERGE_SIMILAR_EDGES.booleanValue) {
+
+            // build the transitions key to find the representing edge
+            // or insert the current edge if no edge was already chosen
+            var key = new EdgeGroupKey(
+                transition.sourceState, 
+                transition.targetState, 
+                transition.preemption, 
+                transition.history, 
+                transition.deferred, 
+                transition.delay,
+                transition.isNondeterministic
+            );
+
+            // if we do not already have a representative use the current edge as the representative
+            val rep = map.computeIfAbsent(key, [EdgeGroupKey _key | edge]); 
+
+            if (edge != rep) {
+                // if this was not just chosen as the representative transfer all edge labels to the representative
+                rep.labels.addAll(edge.labels)
+                for (label : edge.labels) {
+                    // adjust the transfered labels parent
+                    label.parent = rep
+                }
+                // remove the current edge from the graph, as it will be represented by the representative edge
+                edge.source.outgoingEdges.remove(edge)
+                edge.target.outgoingEdges.remove(edge)
+            }
+
+        }
+    }
+
+}