1 files changed, 88 insertions, 0 deletions

diff --git a/subprojects/viatra-runtime-localsearch/src/main/java/tools/refinery/viatra/runtime/localsearch/operations/ISearchOperation.java b/subprojects/viatra-runtime-localsearch/src/main/java/tools/refinery/viatra/runtime/localsearch/operations/ISearchOperation.java
new file mode 100644
index 00000000..eb6243ed
--- /dev/null
+++ b/subprojects/viatra-runtime-localsearch/src/main/java/tools/refinery/viatra/runtime/localsearch/operations/ISearchOperation.java
@@ -0,0 +1,88 @@
+/*******************************************************************************
+ * Copyright (c) 2010-2013, Zoltan Ujhelyi, Akos Horvath, 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;
+
+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.matchers.ViatraQueryRuntimeException;
+
+/**
+ * Represents a search operation executable by the LS engine. It is expected that an operation can be shared among
+ * multiple LS matchers, but the created executors are not.
+ * 
+ * @author Zoltan Ujhelyi
+ * 
+ */
+public interface ISearchOperation {
+
+    /**
+     * Initializes a new operation executor for the given operation. Repeated calls must return different executor
+     * instances.
+     * 
+     * @since 2.0
+     */
+    public ISearchOperationExecutor createExecutor();
+    
+    /**
+     * 
+     * @since 2.0
+     *
+     */
+    public interface ISearchOperationExecutor {
+        
+        /**
+         * Returns the stateless operation this executor was initialized from
+         */
+        ISearchOperation getOperation();
+        
+        /**
+         * During the execution of the corresponding plan, the onInitialize callback is evaluated before the execution of
+         * the operation may begin. Operations may use this method to initialize its internal data structures.
+         * 
+         * @throws ViatraQueryRuntimeException
+         */
+        void onInitialize(MatchingFrame frame, ISearchContext context);
+    
+        /**
+         * After the execution of the operation failed and {@link #execute(MatchingFrame, ISearchContext)} returns false, the onBacktrack
+         * callback is evaluated. Operations may use this method to clean up any temporary structures, and make the
+         * operation ready for a new execution.
+         * 
+         * @throws ViatraQueryRuntimeException
+         */
+        void onBacktrack(MatchingFrame frame, ISearchContext context);
+    
+        /**
+         * 
+         * @param frame
+         * @param context
+         * @return true if successful, or false if backtracking needed
+         * @throws ViatraQueryRuntimeException
+         */
+        boolean execute(MatchingFrame frame, ISearchContext context);
+    }
+    /**
+     * 
+     * @return the ordered list of the variable numbers that are affected by the search operation
+     */
+    List<Integer> getVariablePositions();
+
+    /**
+     * Creates a string representation of the search operation by replacing the variable numbers according to the
+     * parameter function. It is expected that the provided function does return a non-null value for each variable
+     * index that is returned by {@link #getVariablePositions()}; otherwise a {@link NullPointerException} will be
+     * thrown during the calculation of the string.
+     * 
+     * @since 2.0
+     */
+    String toString(Function<Integer, String> variableMapping);
+}