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diff --git a/Solvers/VIATRA-Solver/org.eclipse.viatra.dse/src/org/eclipse/viatra/dse/util/ValueComparableEObjectStringMap.java b/Solvers/VIATRA-Solver/org.eclipse.viatra.dse/src/org/eclipse/viatra/dse/util/ValueComparableEObjectStringMap.java
new file mode 100644
index 00000000..49af05d1
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+++ b/Solvers/VIATRA-Solver/org.eclipse.viatra.dse/src/org/eclipse/viatra/dse/util/ValueComparableEObjectStringMap.java
@@ -0,0 +1,63 @@
+/*******************************************************************************
+ * Copyright (c) 2010-2015, Andras Szabolcs Nagy and Daniel Varro
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v. 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-v20.html.
+ * 
+ * SPDX-License-Identifier: EPL-2.0
+ *******************************************************************************/
+package org.eclipse.viatra.dse.util;
+
+import java.util.Comparator;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.TreeMap;
+
+import org.eclipse.emf.ecore.EObject;
+
+import com.google.common.base.Functions;
+import com.google.common.collect.Ordering;
+
+/**
+ * 
+ * This custom {@link TreeMap} implementation enables to store {@link EObject}-{@link String} pairs sorted by values
+ * (strings). It works as expected if the map is modified in any way, hence the map will still be sorted by values on
+ * the new set of entries.
+ * 
+ * It is allowed to have two entries with the same EObject key (and also with same values).
+ * 
+ * The short coming of the class is that EObjects are compared to each other by their
+ * {@link System#identityHashCode(Object)}, which may lead to unexpected errors.
+ * 
+ * @author Andras Szabolcs Nagy
+ *
+ */
+public class ValueComparableEObjectStringMap extends TreeMap<EObject, String> {
+
+    private static final class EObjectComparator implements Comparator<EObject> {
+        @Override
+        public int compare(EObject o1, EObject o2) {
+            return Integer.valueOf(System.identityHashCode(o1)).compareTo(Integer.valueOf(System.identityHashCode(o2)));
+        }
+    }
+
+    private final Map<EObject, String> innerMap;
+
+    public ValueComparableEObjectStringMap() {
+        this(new HashMap<EObject, String>());
+    }
+
+    private ValueComparableEObjectStringMap(Map<EObject, String> innerMap) {
+        super(Ordering.natural().onResultOf(Functions.forMap(innerMap)).compound(new EObjectComparator()));
+        this.innerMap = innerMap;
+    }
+
+    @Override
+    public String put(EObject keyEObject, String stringValue) {
+        if (innerMap.containsKey(keyEObject)) {
+            remove(keyEObject);
+        }
+        innerMap.put(keyEObject, stringValue);
+        return super.put(keyEObject, stringValue);
+    }
+}