1 files changed, 44 insertions, 0 deletions

diff --git a/subprojects/interpreter/src/main/java/tools/refinery/interpreter/matchers/util/PurgableCache.java b/subprojects/interpreter/src/main/java/tools/refinery/interpreter/matchers/util/PurgableCache.java
new file mode 100644
index 00000000..af969ba4
--- /dev/null
+++ b/subprojects/interpreter/src/main/java/tools/refinery/interpreter/matchers/util/PurgableCache.java
@@ -0,0 +1,44 @@
+/*******************************************************************************
+ * Copyright (c) 2010-2017, Zoltan Ujhelyi, IncQuery Labs Ltd.
+ * 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.interpreter.matchers.util;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.function.Supplier;
+
+/**
+ * @author Zoltan Ujhelyi
+ * @since 1.7
+ * @noreference This class is not intended to be referenced by clients.
+ */
+public class PurgableCache implements ICache {
+
+    Map<Object, Object> storage = new HashMap<>();
+
+    @Override
+    @SuppressWarnings("unchecked")
+    public <T> T getValue(Object key, Class<? extends T> clazz, Supplier<T> valueProvider) {
+        if (storage.containsKey(key)) {
+            Object value = storage.get(key);
+            Preconditions.checkState(clazz.isInstance(value), "Cache stores for key %s a value of %s that is incompatible with the requested type %s", key, value, clazz);
+            return (T) value;
+        } else {
+            T value = valueProvider.get();
+            storage.put(key, value);
+            return value;
+        }
+    }
+
+    /**
+     * Removes all values stored in the cache
+     */
+    public void purge() {
+        storage.clear();
+    }
+}