Github user nickwallen commented on a diff in the pull request:
https://github.com/apache/metron/pull/990#discussion_r183103619
--- Diff:
metron-stellar/stellar-common/src/main/java/org/apache/metron/stellar/common/CachingStellarProcessor.java
---
@@ -0,0 +1,140 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.metron.stellar.common;
+
+import com.github.benmanes.caffeine.cache.Cache;
+import com.github.benmanes.caffeine.cache.Caffeine;
+import org.apache.metron.stellar.common.utils.ConversionUtils;
+import org.apache.metron.stellar.dsl.Context;
+import org.apache.metron.stellar.dsl.VariableResolver;
+import org.apache.metron.stellar.dsl.functions.resolver.FunctionResolver;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Optional;
+import java.util.Set;
+import java.util.concurrent.TimeUnit;
+
+/**
+ * The Caching Stellar Processor is a stellar processor that optionally
fronts stellar with an expression-by-expression
+ * LFU cache.
+ */
+public class CachingStellarProcessor extends StellarProcessor {
--- End diff --
Where are the unit tests for the `CachingStellarProcessor`?
---
