Github user paul-rogers commented on a diff in the pull request:
https://github.com/apache/drill/pull/957#discussion_r140936344
--- Diff:
exec/java-exec/src/main/java/org/apache/drill/exec/server/options/PersistedOptionValue.java
---
@@ -0,0 +1,310 @@
+/**
+ * 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.drill.exec.server.options;
+
+import com.fasterxml.jackson.annotation.JsonIgnore;
+import com.fasterxml.jackson.annotation.JsonInclude;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.core.JsonParser;
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.core.ObjectCodec;
+import com.fasterxml.jackson.databind.DeserializationContext;
+import com.fasterxml.jackson.databind.JavaType;
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
+import com.fasterxml.jackson.databind.deser.std.StdDeserializer;
+import com.google.common.base.Preconditions;
+
+import java.io.IOException;
+
+/**
+ * <p>
+ * This represents a persisted {@link OptionValue}. Decoupling the {@link
OptionValue} from what
+ * is persisted will prevent us from accidentally breaking backward
compatibility in the future
+ * when the {@link OptionValue} changes. Additionally when we do change
the format of stored options we
+ * will not have to change much code since this is already designed with
backward compatibility in mind.
--- End diff --
Nice!
---
