1 files changed, 75 insertions, 0 deletions

diff --git a/subprojects/viatra-runtime-localsearch/src/main/java/tools/refinery/viatra/runtime/localsearch/operations/extend/ExtendConstant.java b/subprojects/viatra-runtime-localsearch/src/main/java/tools/refinery/viatra/runtime/localsearch/operations/extend/ExtendConstant.java
new file mode 100644
index 00000000..455236f3
--- /dev/null
+++ b/subprojects/viatra-runtime-localsearch/src/main/java/tools/refinery/viatra/runtime/localsearch/operations/extend/ExtendConstant.java
@@ -0,0 +1,75 @@
+/*******************************************************************************
+ * Copyright (c) 2010-2014, Marton Bur, Akos Horvath, Zoltan Ujhelyi, Istvan Rath 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.localsearch.operations.extend;
+
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.Iterator;
+import java.util.List;
+import java.util.function.Function;
+
+import tools.refinery.viatra.runtime.localsearch.MatchingFrame;
+import tools.refinery.viatra.runtime.localsearch.matcher.ISearchContext;
+import tools.refinery.viatra.runtime.localsearch.operations.ISearchOperation;
+
+/**
+ * This operation handles constants in search plans by binding a variable to a constant value. Such operations should be
+ * executed as early as possible during plan execution.
+ * 
+ * @author Marton Bur
+ *
+ */
+public class ExtendConstant implements ISearchOperation {
+
+    private class Executor extends SingleValueExtendOperationExecutor<Object> {
+
+        public Executor(int position) {
+            super(position);
+        }
+
+        @Override
+        public Iterator<?> getIterator(MatchingFrame frame, ISearchContext context) {
+            return Collections.singletonList(value).iterator();
+        }
+        
+        @Override
+        public ISearchOperation getOperation() {
+            return ExtendConstant.this;
+        }
+    }
+    
+    private final Object value;
+    private final int position;
+
+    public ExtendConstant(int position, Object value) {
+        this.position = position;
+        this.value = value;
+    }
+
+    @Override
+    public ISearchOperationExecutor createExecutor() {
+        return new Executor(position);
+    }
+
+    @Override
+    public List<Integer> getVariablePositions() {
+        return Arrays.asList(position);
+    }
+    
+    @Override
+    public String toString() {
+        return toString(Object::toString);
+    }
+    
+    @Override
+    public String toString(Function<Integer, String> variableMapping) {
+        return "extend    constant -"+variableMapping.apply(position)+"='"+value+"'";
+    }
+    
+}