1 files changed, 39 insertions, 0 deletions

diff --git a/subprojects/viatra-runtime/src/main/java/tools/refinery/viatra/runtime/matchers/context/IQueryCacheContext.java b/subprojects/viatra-runtime/src/main/java/tools/refinery/viatra/runtime/matchers/context/IQueryCacheContext.java
new file mode 100644
index 00000000..617207f6
--- /dev/null
+++ b/subprojects/viatra-runtime/src/main/java/tools/refinery/viatra/runtime/matchers/context/IQueryCacheContext.java
@@ -0,0 +1,39 @@
+/*******************************************************************************
+ * Copyright (c) 2010-2015, 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.context;
+
+import tools.refinery.viatra.runtime.matchers.ViatraQueryRuntimeException;
+import tools.refinery.viatra.runtime.matchers.backend.IQueryBackend;
+import tools.refinery.viatra.runtime.matchers.backend.IQueryResultProvider;
+import tools.refinery.viatra.runtime.matchers.psystem.queries.PQuery;
+
+/**
+ * Provides information on already cached queries to query evaluator backends at runtime.
+ * 
+ * @author Bergmann Gabor
+ *
+ */
+public interface IQueryCacheContext {
+    
+    /**
+     * Checks if there already is a caching result provider for the given query.
+     * <p> Returns false if called while the caching result provider of the given query is being constructed in the first place. 
+     */
+    public boolean isResultCached(PQuery query);
+    
+    /**
+     * Returns a caching result provider for the given query; it must be constructed if it does not exist yet.
+     * <p> <b>Caution:</b> behavior undefined if called while the caching result provider of the given query is being constructed. 
+     *   Beware of infinite loops. 
+     * <p> <b>Postcondition:</b> {@link IQueryBackend#isCaching()} returns true for the {@link #getQueryBackend()} of the returned provider
+     * 
+     * @throws ViatraQueryRuntimeException
+     */
+    public IQueryResultProvider getCachingResultProvider(PQuery query);
+}