1 files changed, 64 insertions, 0 deletions

diff --git a/store/src/main/java/tools/refinery/data/query/internal/RelationUpdateListenerEntry.java b/store/src/main/java/tools/refinery/data/query/internal/RelationUpdateListenerEntry.java
new file mode 100644
index 00000000..45be26b1
--- /dev/null
+++ b/store/src/main/java/tools/refinery/data/query/internal/RelationUpdateListenerEntry.java
@@ -0,0 +1,64 @@
+package tools.refinery.data.query.internal;
+
+import java.util.Arrays;
+import java.util.Objects;
+
+import org.eclipse.viatra.query.runtime.matchers.context.IQueryRuntimeContextListener;
+import org.eclipse.viatra.query.runtime.matchers.tuple.ITuple;
+import org.eclipse.viatra.query.runtime.matchers.tuple.Tuples;
+
+import tools.refinery.data.model.Tuple;
+import tools.refinery.data.query.view.RelationView;
+
+public class RelationUpdateListenerEntry<D> {
+        final RelationView<D> key;
+        final ITuple filter;
+        final IQueryRuntimeContextListener listener;
+        
+        public RelationUpdateListenerEntry(RelationView<D> key, ITuple filter, IQueryRuntimeContextListener listener) {
+                super();
+                this.key = key;
+                this.filter = filter;
+                this.listener = listener;
+        }
+        
+        public void processChange(Tuple tuple, D oldValue, D newValue) {
+                Object[] oldTuple = isMatching(key.getWrappedKey().transform(tuple, oldValue), filter);
+                Object[] newTuple = isMatching(key.getWrappedKey().transform(tuple, newValue), filter);
+                
+                if(!Arrays.equals(oldTuple, newTuple)) {
+                        if(oldTuple != null) {
+                                listener.update(key, Tuples.flatTupleOf(oldTuple), false);
+                        }
+                        if(newTuple != null) {
+                                listener.update(key, Tuples.flatTupleOf(newTuple), true);
+                        }
+                }
+        }
+        
+        private Object[] isMatching(Object[] tuple, ITuple filter) {
+                for(int i = 0; i<filter.getSize(); i++) {
+                        final Object filterObject = filter.get(i);
+                        if(filterObject != null && !filterObject.equals(tuple[i])) {
+                                return null;
+                        }
+                }
+                return tuple;
+        }
+
+        @Override
+        public int hashCode() {
+                return Objects.hash(filter, key, listener);
+        }
+
+        @Override
+        public boolean equals(Object obj) {
+                if (this == obj)
+                        return true;
+                if (!(obj instanceof RelationUpdateListenerEntry))
+                        return false;
+                RelationUpdateListenerEntry<?> other = (RelationUpdateListenerEntry<?>) obj;
+                return Objects.equals(filter, other.filter) && Objects.equals(key, other.key)
+                                && Objects.equals(listener, other.listener);
+        }
+}