1 files changed, 49 insertions, 0 deletions

diff --git a/subprojects/viatra-runtime-rete/src/main/java/tools/refinery/viatra/runtime/rete/construction/quasitree/JoinOrderingHeuristics.java b/subprojects/viatra-runtime-rete/src/main/java/tools/refinery/viatra/runtime/rete/construction/quasitree/JoinOrderingHeuristics.java
new file mode 100644
index 00000000..0ea7c1d9
--- /dev/null
+++ b/subprojects/viatra-runtime-rete/src/main/java/tools/refinery/viatra/runtime/rete/construction/quasitree/JoinOrderingHeuristics.java
@@ -0,0 +1,49 @@
+/*******************************************************************************
+ * Copyright (c) 2004-2010 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.construction.quasitree;
+
+import java.util.Comparator;
+
+import tools.refinery.viatra.runtime.rete.util.Options;
+import tools.refinery.viatra.runtime.rete.util.OrderingCompareAgent;
+
+/**
+ * @author Gabor Bergmann
+ * 
+ */
+public class JoinOrderingHeuristics implements Comparator<JoinCandidate> {
+
+    @Override
+    public int compare(JoinCandidate jc1, JoinCandidate jc2) {
+        return new OrderingCompareAgent<JoinCandidate>(jc1, jc2) {
+            @Override
+            protected void doCompare() {
+                swallowBoolean(true && consider(preferTrue(a.isTrivial(), b.isTrivial()))
+                        && consider(preferTrue(a.isSubsumption(), b.isSubsumption()))
+                        && consider(preferTrue(a.isCheckOnly(), b.isCheckOnly()))
+                        && consider( 
+                                Options.functionalDependencyOption == Options.FunctionalDependencyOption.OFF ?
+                                dontCare() :
+                                preferTrue(a.isHeath(), b.isHeath())
+                            )
+                        && consider(preferFalse(a.isDescartes(), b.isDescartes()))
+
+                        // TODO main heuristic decisions
+
+                        // tie breaking
+                        && consider(preferLess(a.getConsPrimary(), b.getConsPrimary(), TieBreaker.CONSTRAINT_LIST_COMPARATOR))
+                        && consider(preferLess(a.getConsSecondary(), b.getConsSecondary(), TieBreaker.CONSTRAINT_LIST_COMPARATOR))
+                        && consider(preferLess(System.identityHashCode(a), System.identityHashCode(b))));
+            }
+        }.compare();
+
+    }
+
+}
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