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diff --git a/subprojects/viatra-runtime-base/src/main/java/tools/refinery/viatra/runtime/base/api/IndexingLevel.java b/subprojects/viatra-runtime-base/src/main/java/tools/refinery/viatra/runtime/base/api/IndexingLevel.java
new file mode 100644
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+++ b/subprojects/viatra-runtime-base/src/main/java/tools/refinery/viatra/runtime/base/api/IndexingLevel.java
@@ -0,0 +1,113 @@
+/*******************************************************************************
+ * Copyright (c) 2010-2016, Grill Balázs, IncQueryLabs
+ * 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 tools.refinery.viatra.runtime.base.api;
+
+import tools.refinery.viatra.runtime.matchers.context.IndexingService;
+
+import java.util.Set;
+
+/**
+ * The values of this enum denotes the level of indexing the base indexer is capable of.
+ *
+ * @author Grill Balázs
+ * @since 1.4
+ *
+ */
+public enum IndexingLevel {
+
+    /**
+     * No indexing is performed
+     */
+    NONE,
+
+    /**
+     * Only cardinality information is stored. This indexing level makes possible to calculate
+     * results of {@link NavigationHelper#countAllInstances(org.eclipse.emf.ecore.EClass)}, {@link NavigationHelper#countFeatures(org.eclipse.emf.ecore.EStructuralFeature)}
+     * and {@link NavigationHelper#countDataTypeInstances(org.eclipse.emf.ecore.EDataType)} with minimal memory footprint.
+     */
+    STATISTICS,
+
+    /**
+     * Notifications are dispatched about the changes
+     */
+    NOTIFICATIONS,
+
+    /**
+     * Cardinality information is stored and live notifications are dispatched
+     */
+    BOTH,
+
+    /**
+     * Full indexing is performed, set of instances is available
+     */
+    FULL
+
+    ;
+
+    private static final IndexingLevel[][] mergeTable = {
+                         /* NONE            STATISTICS  NOTIFICATIONS   BOTH     FULL*/
+       /* NONE          */{ NONE,           STATISTICS, NOTIFICATIONS,  BOTH,    FULL},
+       /* STATISTICS    */{ STATISTICS,     STATISTICS, BOTH,           BOTH,    FULL},
+       /* NOTIFICATIONS */{ NOTIFICATIONS,  BOTH,       NOTIFICATIONS,  BOTH,    FULL},
+       /* BOTH          */{ BOTH,           BOTH,       BOTH,           BOTH,    FULL},
+       /* FULL          */{ FULL,           FULL,       FULL,           FULL,    FULL}
+    };
+
+    public static IndexingLevel toLevel(IndexingService service){
+        switch(service){
+        case INSTANCES:
+            return IndexingLevel.FULL;
+        case NOTIFICATIONS:
+            return IndexingLevel.NOTIFICATIONS;
+        case STATISTICS:
+            return IndexingLevel.STATISTICS;
+        default:
+           return IndexingLevel.NONE;
+        }
+    }
+
+    public static IndexingLevel toLevel(Set<IndexingService> services){
+        IndexingLevel result = NONE;
+        for(IndexingService service : services){
+            result = result.merge(toLevel(service));
+        }
+        return result;
+    }
+
+    /**
+     * Merge this level with the given other level, The resulting indexing level will provide the
+     * functionality which conforms to both given levels.
+     */
+    public IndexingLevel merge(IndexingLevel other){
+        if (other == null) return this;
+        return mergeTable[this.ordinal()][other.ordinal()];
+    }
+
+    /**
+     * Tells whether the indexer shall perform separate statistics calculation for this level
+     */
+    public boolean hasStatistics() {
+        return this == IndexingLevel.BOTH || this == IndexingLevel.STATISTICS || this == IndexingLevel.FULL;
+    }
+
+    /**
+     * Tells whether the indexer shall perform instance indexing
+     */
+    public boolean hasInstances(){
+        return this == IndexingLevel.FULL;
+    }
+
+    /**
+     * Returns whether the current indexing level includes all features from the parameter level
+     * @since 1.5
+     */
+    public boolean providesLevel(IndexingLevel level) {
+        return this.merge(level) == this;
+    }
+}