diff --git a/control/json/utils/modifier.hpp b/control/json/utils/modifier.hpp
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+/**
+ * Copyright © 2021 IBM Corporation
+ *
+ * Licensed 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.
+ */
+#pragma once
+
+#include "config_base.hpp"
+
+#include <string>
+#include <vector>
+
+namespace phosphor::fan::control::json
+{
+
+using json = nlohmann::json;
+
+/**
+ * @class Modifier
+ *
+ * This class provides a doOp() function to modify a PropertyVariantType value
+ * based on a JSON config passed into its constructor.
+ *
+ * For example, with the JSON:
+ * {
+ *   "operator": "minus",
+ *   "value": 3
+ * }
+ *
+ * When doOp() is called, it will subtract 3 from the value passed
+ * into doOp() and return the result.
+ *
+ * The valid operators are:
+ *  - "minus"
+ *
+ * To add a new operator, derive a new class from BaseOperator and
+ * then create it accordingly in setOperator.
+ */
+class Modifier
+{
+  public:
+    /**
+     * @brief Base class for operators
+     */
+    struct BaseOperator
+    {
+        virtual PropertyVariantType operator()(double val) = 0;
+
+        virtual PropertyVariantType operator()(int32_t val) = 0;
+
+        virtual PropertyVariantType operator()(int64_t val) = 0;
+
+        virtual PropertyVariantType operator()(const std::string& val) = 0;
+
+        virtual PropertyVariantType operator()(bool val) = 0;
+    };
+
+    Modifier() = delete;
+    ~Modifier() = default;
+    Modifier(const Modifier&) = delete;
+    Modifier& operator=(const Modifier&) = delete;
+    Modifier(Modifier&&) = delete;
+    Modifier& operator=(Modifier&&) = delete;
+
+    /**
+     * @brief Constructor
+     *
+     * @param[in] jsonObj - The JSON config object
+     */
+    Modifier(const json& jsonObj);
+
+    /**
+     * @brief Performs the operation
+     *
+     * @param[in] value - The variant to do the operation on
+     *
+     * @return PropertyVariantType - The result
+     */
+    PropertyVariantType doOp(const PropertyVariantType& value);
+
+  private:
+    /**
+     * @brief Parse and set the value
+     *
+     * @param[in] jsonObj - The JSON config object
+     */
+    void setValue(const json& jsonObj);
+
+    /**
+     * @brief Parse and set the operator
+     *
+     * @param[in] jsonObj - The JSON config object
+     */
+    void setOperator(const json& jsonObj);
+
+    /**
+     * @brief Subtracts _value from value
+     *
+     * @param[in] value - The value to subtract from
+     */
+    PropertyVariantType minus(const PropertyVariantType& value);
+
+    /** @brief The value used by the operator */
+    PropertyVariantType _value;
+
+    /** @brief The operator that will be used */
+    std::unique_ptr<BaseOperator> _operator;
+};
+
+} // namespace phosphor::fan::control::json