1 files changed, 90 insertions, 0 deletions

diff --git a/subprojects/viatra-runtime/src/main/java/tools/refinery/viatra/runtime/matchers/planning/operations/PStart.java b/subprojects/viatra-runtime/src/main/java/tools/refinery/viatra/runtime/matchers/planning/operations/PStart.java
new file mode 100644
index 00000000..9e6ea10e
--- /dev/null
+++ b/subprojects/viatra-runtime/src/main/java/tools/refinery/viatra/runtime/matchers/planning/operations/PStart.java
@@ -0,0 +1,90 @@
+/*******************************************************************************
+ * Copyright (c) 2010-2014, Bergmann Gabor, 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.matchers.planning.operations;
+
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.Set;
+import java.util.stream.Collectors;
+
+import tools.refinery.viatra.runtime.matchers.psystem.PConstraint;
+import tools.refinery.viatra.runtime.matchers.psystem.PVariable;
+
+/**
+ * No constraints, and no parent SubPlan, just a (possibly empty) set of a priori known (input) variables. Satisfied by a single tuple.
+ * 
+ * <p> Can also be used without a priori variables, 
+ *   e.g. as a "virtual parent" in extreme cases, 
+ *   such as <code>pattern foo(Bar) = {Bar = eval (3*4)} </code> 
+ * 
+ * @author Bergmann Gabor
+ *
+ */
+public class PStart extends POperation {
+    
+    private Set<PVariable> aPrioriVariables;
+
+    
+    public PStart(Set<PVariable> aPrioriVariables) {
+        super();
+        this.aPrioriVariables = aPrioriVariables;
+    }
+    public PStart(PVariable... aPrioriVariables) {
+        this(new HashSet<PVariable>(Arrays.asList(aPrioriVariables)));
+    }
+    public Set<PVariable> getAPrioriVariables() {
+        return aPrioriVariables;
+    }
+
+    @Override
+    public String getShortName() {
+        return aPrioriVariables.stream().map(PVariable::getName).collect(Collectors.joining(",", "START_{", "}"));
+    }
+    @Override
+    public int numParentSubPlans() {
+        return 0;
+    }
+
+    @Override
+    public Set<? extends PConstraint> getDeltaConstraints() {
+        return Collections.emptySet();
+    }
+
+    @Override
+    public int hashCode() {
+        final int prime = 31;
+        int result = 1;
+        result = prime
+                * result
+                + ((aPrioriVariables == null) ? 0 : aPrioriVariables.hashCode());
+        return result;
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj)
+            return true;
+        if (obj == null)
+            return false;
+        if (!(obj instanceof PStart))
+            return false;
+        PStart other = (PStart) obj;
+        if (aPrioriVariables == null) {
+            if (other.aPrioriVariables != null)
+                return false;
+        } else if (!aPrioriVariables.equals(other.aPrioriVariables))
+            return false;
+        return true;
+    }
+
+
+    
+    
+}