1 files changed, 99 insertions, 0 deletions

diff --git a/subprojects/viatra-runtime/src/main/java/tools/refinery/viatra/runtime/matchers/psystem/basicdeferred/BaseTypeSafeConstraint.java b/subprojects/viatra-runtime/src/main/java/tools/refinery/viatra/runtime/matchers/psystem/basicdeferred/BaseTypeSafeConstraint.java
new file mode 100644
index 00000000..7bc949a8
--- /dev/null
+++ b/subprojects/viatra-runtime/src/main/java/tools/refinery/viatra/runtime/matchers/psystem/basicdeferred/BaseTypeSafeConstraint.java
@@ -0,0 +1,99 @@
+/*******************************************************************************
+ * 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.matchers.psystem.basicdeferred;
+
+import java.util.Collections;
+import java.util.Set;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+import tools.refinery.viatra.runtime.matchers.context.IQueryMetaContext;
+import tools.refinery.viatra.runtime.matchers.planning.SubPlan;
+import tools.refinery.viatra.runtime.matchers.psystem.PBody;
+import tools.refinery.viatra.runtime.matchers.psystem.PVariable;
+import tools.refinery.viatra.runtime.matchers.psystem.TypeJudgement;
+import tools.refinery.viatra.runtime.matchers.psystem.VariableDeferredPConstraint;
+
+/**
+ * @author Gabor Bergmann
+ * 
+ */
+public abstract class BaseTypeSafeConstraint extends
+        VariableDeferredPConstraint {
+    
+    protected Set<PVariable> inputVariables;
+    protected PVariable outputVariable;
+
+    public PVariable getOutputVariable() {
+        return outputVariable;
+    }
+
+    /**
+     * @param pBody
+     * @param inputVariables
+     * @param outputVariable null iff no output (check-only)
+     */
+    public BaseTypeSafeConstraint(PBody pBody,
+            Set<PVariable> inputVariables, final PVariable outputVariable) {
+        super(pBody, 
+                (outputVariable == null) ? 
+                        inputVariables : 
+                            Stream.concat(inputVariables.stream(), Stream.of(outputVariable)).collect(Collectors.toSet())
+                    );
+        this.inputVariables = inputVariables;
+        this.outputVariable = outputVariable;
+    }
+
+    @Override
+    public Set<PVariable> getDeducedVariables() {
+        if (outputVariable == null) 
+            return Collections.emptySet(); 
+        else
+            return Collections.singleton(outputVariable);
+    }
+
+    @Override
+    public Set<PVariable> getDeferringVariables() {
+        return inputVariables;
+    }
+
+    @Override
+    public boolean isReadyAt(SubPlan plan, IQueryMetaContext context) {
+        if (super.isReadyAt(plan, context)) {
+            return checkTypeSafety(plan, context) == null;
+        }
+        return false;
+    }
+
+    /**
+     * Checks whether all type restrictions are already enforced on affected variables.
+     * 
+     * @param plan
+     * @return a variable whose type safety is not enforced yet, or null if the plan is typesafe
+     */
+    public PVariable checkTypeSafety(SubPlan plan, IQueryMetaContext context) {
+        Set<TypeJudgement> impliedJudgements = plan.getAllImpliedTypeJudgements(context);
+        
+        for (PVariable pVariable : inputVariables) {
+            Set<TypeJudgement> allTypeRestrictionsForVariable = pBody.getAllUnaryTypeRestrictions(context).get(pVariable);
+            if (allTypeRestrictionsForVariable != null && !impliedJudgements.containsAll(allTypeRestrictionsForVariable))
+                return pVariable;
+        }
+        return null;
+    }
+    
+    @Override
+    protected void doReplaceVariable(PVariable obsolete, PVariable replacement) {
+        if (inputVariables.remove(obsolete)) 
+            inputVariables.add(replacement);
+        if (outputVariable == obsolete) 
+            outputVariable = replacement;
+    }
+}