1 files changed, 51 insertions, 0 deletions

diff --git a/store/src/main/java/org/eclipse/viatra/solver/data/query/internal/RelationUpdateListener.java b/store/src/main/java/org/eclipse/viatra/solver/data/query/internal/RelationUpdateListener.java
new file mode 100644
index 00000000..c6d12614
--- /dev/null
+++ b/store/src/main/java/org/eclipse/viatra/solver/data/query/internal/RelationUpdateListener.java
@@ -0,0 +1,51 @@
+package org.eclipse.viatra.solver.data.query.internal;
+
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
+
+import org.eclipse.viatra.query.runtime.matchers.context.IQueryRuntimeContextListener;
+import org.eclipse.viatra.query.runtime.matchers.tuple.ITuple;
+import org.eclipse.viatra.solver.data.model.Tuple;
+import org.eclipse.viatra.solver.data.query.view.RelationView;
+
+public class RelationUpdateListener {
+        private final Map<RelationView<?>,Set<RelationUpdateListenerEntry<?>>> view2Listeners;
+        
+        public RelationUpdateListener(Set<RelationView<?>> relationViews) {
+                view2Listeners = new HashMap<>();
+                for(RelationView<?> relationView : relationViews) {
+                        view2Listeners.put(relationView, new HashSet<>());
+                }
+        }
+        public boolean containsRelationalView(RelationView<?> relationalKey) {
+                RelationView<?> relationView = relationalKey.getWrappedKey();
+                return view2Listeners.containsKey(relationView);
+        }
+        public void addListener(RelationView<?> relationalKey, ITuple seed, IQueryRuntimeContextListener listener) {
+                RelationView<?> relationView = relationalKey.getWrappedKey();
+                if(view2Listeners.containsKey(relationView)) {
+                        RelationUpdateListenerEntry<?> entry = new RelationUpdateListenerEntry<>(relationalKey, seed, listener);
+                        view2Listeners.get(relationView).add(entry);
+                } else throw new IllegalArgumentException();
+        }
+        public void removeListener(RelationView<?> relationalKey, ITuple seed, IQueryRuntimeContextListener listener) {
+                RelationView<?> relationView = relationalKey.getWrappedKey();
+                if(view2Listeners.containsKey(relationView)) {
+                        RelationUpdateListenerEntry<?> entry = new RelationUpdateListenerEntry<>(relationalKey, seed, listener);
+                        view2Listeners.get(relationView).remove(entry);
+                } else throw new IllegalArgumentException();
+        }
+        
+        public <D> void processChange(RelationView<D> relationView, Tuple tuple, D oldValue, D newValue) {
+                Set<RelationUpdateListenerEntry<?>> listeners = view2Listeners.get(relationView);
+                if(listeners != null) {
+                        for(RelationUpdateListenerEntry<?> listener : listeners) {
+                                @SuppressWarnings("unchecked")
+                                RelationUpdateListenerEntry<D> typeCorrectListener = (RelationUpdateListenerEntry<D>) listener;
+                                typeCorrectListener.processChange(tuple, oldValue, newValue);
+                        }
+                } else throw new IllegalArgumentException("View was not indexed in constructor "+relationView);
+        }
+}