1 files changed, 26 insertions, 0 deletions

diff --git a/subprojects/viatra-runtime-rete/src/main/java/tools/refinery/viatra/runtime/rete/aggregation/IAggregatorNode.java b/subprojects/viatra-runtime-rete/src/main/java/tools/refinery/viatra/runtime/rete/aggregation/IAggregatorNode.java
new file mode 100644
index 00000000..6c286364
--- /dev/null
+++ b/subprojects/viatra-runtime-rete/src/main/java/tools/refinery/viatra/runtime/rete/aggregation/IAggregatorNode.java
@@ -0,0 +1,26 @@
+/*******************************************************************************
+ * Copyright (c) 2010-2016, Gabor Bergmann, IncQueryLabs Ltd.
+ * 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.rete.aggregation;
+
+import tools.refinery.viatra.runtime.rete.index.Indexer;
+
+/**
+ * Expresses that aggregators expose specialized non-enumerable indexers for outer joining.
+ * @author Gabor Bergmann
+ *
+ * @since 1.4
+ * 
+ */
+public interface IAggregatorNode {
+
+    Indexer getAggregatorOuterIndexer();
+
+    Indexer getAggregatorOuterIdentityIndexer(int resultPositionInSignature);
+
+}
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