1 files changed, 69 insertions, 0 deletions

diff --git a/subprojects/viatra-runtime-rete/src/main/java/tools/refinery/viatra/runtime/rete/single/FilterNode.java b/subprojects/viatra-runtime-rete/src/main/java/tools/refinery/viatra/runtime/rete/single/FilterNode.java
new file mode 100644
index 00000000..f66f1715
--- /dev/null
+++ b/subprojects/viatra-runtime-rete/src/main/java/tools/refinery/viatra/runtime/rete/single/FilterNode.java
@@ -0,0 +1,69 @@
+/*******************************************************************************
+ * 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.single;
+
+import java.util.Collection;
+import java.util.Map;
+import java.util.Map.Entry;
+
+import tools.refinery.viatra.runtime.matchers.tuple.Tuple;
+import tools.refinery.viatra.runtime.matchers.util.Direction;
+import tools.refinery.viatra.runtime.matchers.util.timeline.Timeline;
+import tools.refinery.viatra.runtime.rete.network.ReteContainer;
+import tools.refinery.viatra.runtime.rete.network.communication.Timestamp;
+
+/**
+ * This node implements a simple filter. A stateless abstract check() predicate determines whether a matching is allowed
+ * to pass.
+ * 
+ * @author Gabor Bergmann
+ * 
+ */
+public abstract class FilterNode extends SingleInputNode {
+
+    public FilterNode(final ReteContainer reteContainer) {
+        super(reteContainer);
+    }
+
+    /**
+     * Abstract filtering predicate. Expected to be stateless.
+     * 
+     * @param ps
+     *            the matching to be checked.
+     * @return true if and only if the parameter matching is allowed to pass through this node.
+     */
+    public abstract boolean check(final Tuple ps);
+
+    @Override
+    public void pullInto(final Collection<Tuple> collector, final boolean flush) {
+        for (final Tuple ps : this.reteContainer.pullPropagatedContents(this, flush)) {
+            if (check(ps)) {
+                collector.add(ps);
+            }
+        }
+    }
+    
+    @Override
+    public void pullIntoWithTimeline(Map<Tuple, Timeline<Timestamp>> collector, boolean flush) {
+        for (final Entry<Tuple, Timeline<Timestamp>> entry : this.reteContainer.pullPropagatedContentsWithTimestamp(this, flush).entrySet()) {
+            if (check(entry.getKey())) {
+                collector.put(entry.getKey(), entry.getValue());
+            }
+        }
+    }
+
+    @Override
+    public void update(final Direction direction, final Tuple updateElement, final Timestamp timestamp) {
+        if (check(updateElement)) {
+            propagateUpdate(direction, updateElement, timestamp);
+        }
+    }
+
+}