1 files changed, 50 insertions, 0 deletions

diff --git a/subprojects/viatra-runtime-rete/src/main/java/tools/refinery/viatra/runtime/rete/misc/ConstantNode.java b/subprojects/viatra-runtime-rete/src/main/java/tools/refinery/viatra/runtime/rete/misc/ConstantNode.java
new file mode 100644
index 00000000..980d3eee
--- /dev/null
+++ b/subprojects/viatra-runtime-rete/src/main/java/tools/refinery/viatra/runtime/rete/misc/ConstantNode.java
@@ -0,0 +1,50 @@
+/*******************************************************************************
+ * Copyright (c) 2004-2008 Gabor Bergmann 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 tools.refinery.viatra.runtime.rete.misc;
+
+import java.util.Collection;
+import java.util.Map;
+
+import tools.refinery.viatra.runtime.matchers.context.IQueryRuntimeContext;
+import tools.refinery.viatra.runtime.matchers.tuple.Tuple;
+import tools.refinery.viatra.runtime.matchers.util.timeline.Timeline;
+import tools.refinery.viatra.runtime.rete.network.ReteContainer;
+import tools.refinery.viatra.runtime.rete.network.StandardNode;
+import tools.refinery.viatra.runtime.rete.network.communication.Timestamp;
+
+/**
+ * Node that always contains a single constant Tuple
+ * 
+ * @author Gabor Bergmann
+ */
+public class ConstantNode extends StandardNode {
+
+    protected Tuple constant;
+
+    /**
+     * @param constant
+     *            will be wrapped using {@link IQueryRuntimeContext#wrapTuple(Tuple)}
+     */
+    public ConstantNode(ReteContainer reteContainer, Tuple constant) {
+        super(reteContainer);
+        this.constant = reteContainer.getNetwork().getEngine().getRuntimeContext().wrapTuple(constant);
+    }
+
+    @Override
+    public void pullInto(Collection<Tuple> collector, boolean flush) {
+        collector.add(constant);
+    }
+
+    @Override
+    public void pullIntoWithTimeline(final Map<Tuple, Timeline<Timestamp>> collector, final boolean flush) {
+        collector.put(constant, Timestamp.INSERT_AT_ZERO_TIMELINE);
+    }
+
+}