1 files changed, 90 insertions, 0 deletions

diff --git a/subprojects/viatra-runtime-rete/src/main/java/tools/refinery/viatra/runtime/rete/construction/basiclinear/OrderingHeuristics.java b/subprojects/viatra-runtime-rete/src/main/java/tools/refinery/viatra/runtime/rete/construction/basiclinear/OrderingHeuristics.java
new file mode 100644
index 00000000..2b4e8890
--- /dev/null
+++ b/subprojects/viatra-runtime-rete/src/main/java/tools/refinery/viatra/runtime/rete/construction/basiclinear/OrderingHeuristics.java
@@ -0,0 +1,90 @@
+/*******************************************************************************
+ * 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.basiclinear;
+
+import java.util.Comparator;
+import java.util.Set;
+
+import tools.refinery.viatra.runtime.matchers.context.IQueryMetaContext;
+import tools.refinery.viatra.runtime.matchers.planning.SubPlan;
+import tools.refinery.viatra.runtime.matchers.psystem.DeferredPConstraint;
+import tools.refinery.viatra.runtime.matchers.psystem.EnumerablePConstraint;
+import tools.refinery.viatra.runtime.matchers.psystem.PConstraint;
+import tools.refinery.viatra.runtime.matchers.psystem.PVariable;
+import tools.refinery.viatra.runtime.matchers.psystem.basicenumerables.ConstantValue;
+import tools.refinery.viatra.runtime.matchers.util.CollectionsFactory;
+import tools.refinery.viatra.runtime.rete.util.OrderingCompareAgent;
+
+/**
+ * @author Gabor Bergmann
+ * 
+ */
+public class OrderingHeuristics implements Comparator<PConstraint> {
+    private SubPlan plan;
+    private IQueryMetaContext context;
+
+    public OrderingHeuristics(SubPlan plan, IQueryMetaContext context) {
+        super();
+        this.plan = plan;
+        this.context = context;
+    }
+
+    @Override
+    public int compare(PConstraint o1, PConstraint o2) {
+        return new OrderingCompareAgent<PConstraint>(o1, o2) {
+            @Override
+            protected void doCompare() {
+                boolean temp = consider(preferTrue(isConstant(a), isConstant(b)))
+                        && consider(preferTrue(isReady(a), isReady(b)));
+                if (!temp)
+                    return;
+
+                Set<PVariable> bound1 = boundVariables(a);
+                Set<PVariable> bound2 = boundVariables(b);
+                swallowBoolean(temp && consider(preferTrue(isBound(a, bound1), isBound(b, bound2)))
+                        && consider(preferMore(degreeBound(a, bound1), degreeBound(b, bound2)))
+                        && consider(preferLess(degreeFree(a, bound1), degreeFree(b, bound2)))
+
+                        // tie breaking
+                        && consider(preferLess(a.getMonotonousID(), b.getMonotonousID())) // this is hopefully deterministic
+                        && consider(preferLess(System.identityHashCode(a), System.identityHashCode(b))));
+            }
+        }.compare();
+    }
+
+    boolean isConstant(PConstraint o) {
+        return (o instanceof ConstantValue);
+    }
+
+    boolean isReady(PConstraint o) {
+        return (o instanceof EnumerablePConstraint)
+                || (o instanceof DeferredPConstraint && ((DeferredPConstraint) o)
+                        .isReadyAt(plan, context));
+    }
+
+    Set<PVariable> boundVariables(PConstraint o) {
+        Set<PVariable> boundVariables = CollectionsFactory.createSet(o.getAffectedVariables());
+        boundVariables.retainAll(plan.getVisibleVariables());
+        return boundVariables;
+    }
+
+    boolean isBound(PConstraint o, Set<PVariable> boundVariables) {
+        return boundVariables.size() == o.getAffectedVariables().size();
+    }
+
+    int degreeBound(PConstraint o, Set<PVariable> boundVariables) {
+        return boundVariables.size();
+    }
+
+    int degreeFree(PConstraint o, Set<PVariable> boundVariables) {
+        return o.getAffectedVariables().size() - boundVariables.size();
+    }
+
+}