diff --git a/DRAMSys/library/src/common/configuration/AddressMapping.cpp b/DRAMSys/library/src/common/configuration/AddressMapping.cpp
index b3277d89..7b2237cc 100644
--- a/DRAMSys/library/src/common/configuration/AddressMapping.cpp
+++ b/DRAMSys/library/src/common/configuration/AddressMapping.cpp
@@ -34,7 +34,6 @@
  */
 
 #include "AddressMapping.h"
-#include "util.h"
 
 #include <iostream>
 
@@ -49,12 +48,11 @@ void to_json(json &j, const AddressMapping &m)
                   {"COLUMN_BIT", m.coloumnBits},
                   {"BANKGROUP_BIT", m.bankGroupBits},
                   {"BANK_BIT", m.bankBits},
-                  {"ROW_BIT", m.rowBits}};
-
-    from_optional("CHANNEL_BIT", congen, m.channelBits);
-    from_optional("BYTE_BIT", congen, m.byteBits);
-    from_optional("BANKGROUP_BIT", congen, m.bankGroupBits);
-    from_optional("XOR", congen, m.xorBits);
+                  {"ROW_BIT", m.rowBits},
+                  {"CHANNEL_BIT", m.channelBits},
+                  {"BYTE_BIT", m.byteBits},
+                  {"BANKGROUP_BIT", m.bankGroupBits},
+                  {"XOR", m.xorBits}};
 
     j["CONGEN"] = congen;
 }
@@ -73,10 +71,17 @@ void from_json(const json &j, AddressMapping &m)
     congen.at("BANK_BIT").get_to(m.bankBits);
     congen.at("ROW_BIT").get_to(m.rowBits);
 
-    get_optional("CHANNEL_BIT", congen, m.channelBits);
-    get_optional("BYTE_BIT", congen, m.byteBits);
-    get_optional("BANKGROUP_BIT", congen, m.bankGroupBits);
-    get_optional("XOR", congen, m.xorBits);
+    if (congen.contains("CHANNEL_BIT"))
+        congen.at("CHANNEL_BIT").get_to(m.channelBits);
+
+    if (congen.contains("BYTE_BIT"))
+        congen.at("BYTE_BIT").get_to(m.byteBits);
+
+    if (congen.contains("BANKGROUP_BIT"))
+        congen.at("BANKGROUP_BIT").get_to(m.bankGroupBits);
+
+    if (congen.contains("XOR"))
+        congen.at("XOR").get_to(m.xorBits);
 }
 
 void to_json(json &j, const XorPair &x)
@@ -90,4 +95,4 @@ void from_json(const json &j, XorPair &x)
     j.at("SECOND").get_to(x.second);
 }
 
-} // namespace Configuration
+} // namespace DRAMSysConfiguration
diff --git a/DRAMSys/library/src/common/configuration/AddressMapping.h b/DRAMSys/library/src/common/configuration/AddressMapping.h
index 07c4cda0..ffcc3ca2 100644
--- a/DRAMSys/library/src/common/configuration/AddressMapping.h
+++ b/DRAMSys/library/src/common/configuration/AddressMapping.h
@@ -33,8 +33,10 @@
  *    Derek Christ
  */
 
-#ifndef ADDRESSMAPPING_H
-#define ADDRESSMAPPING_H
+#ifndef DRAMSYSCONFIGURATION_ADDRESSMAPPING_H
+#define DRAMSYSCONFIGURATION_ADDRESSMAPPING_H
+
+#include "util.h"
 
 #include <nlohmann/json.hpp>
 #include <unordered_set>
@@ -56,13 +58,13 @@ void from_json(const json &j, XorPair &x);
 
 struct AddressMapping
 {
-    std::pair<std::unordered_set<unsigned int>, bool> byteBits;
+    Optional<std::unordered_set<unsigned int>> byteBits;
     std::unordered_set<unsigned int> coloumnBits;
     std::unordered_set<unsigned int> bankBits;
-    std::pair<std::unordered_set<unsigned int>, bool> bankGroupBits;
+    Optional<std::unordered_set<unsigned int>> bankGroupBits;
     std::unordered_set<unsigned int> rowBits;
-    std::pair<std::unordered_set<unsigned int>, bool> channelBits;
-    std::pair<std::vector<XorPair>, bool> xorBits;
+    Optional<std::unordered_set<unsigned int>> channelBits;
+    Optional<std::vector<XorPair>> xorBits;
 };
 
 void to_json(json &j, const AddressMapping &m);
diff --git a/DRAMSys/library/src/common/configuration/CMakeLists.txt b/DRAMSys/library/src/common/configuration/CMakeLists.txt
index d62c5fdc..bd199eae 100644
--- a/DRAMSys/library/src/common/configuration/CMakeLists.txt
+++ b/DRAMSys/library/src/common/configuration/CMakeLists.txt
@@ -32,6 +32,7 @@
 #   Derek Christ
 
 set(JSON_BuildTests OFF CACHE INTERNAL "")
+set(JSON_ImplicitConversions OFF CACHE INTERNAL "")
 add_subdirectory(${CMAKE_SOURCE_DIR}/library/src/common/third_party/nlohmann ${CMAKE_CURRENT_BINARY_DIR}/nlohmann)
 
 option(DRAMSYS_CONFIGURATION_TESTS "Build the unit tests for configuration." OFF)
@@ -56,5 +57,6 @@ add_library(DRAMSysConfiguration STATIC
 
 target_compile_definitions(DRAMSysConfiguration PRIVATE DRAMSysResourceDirectory="${CMAKE_SOURCE_DIR}/library/resources")
 
-target_link_libraries(DRAMSysConfiguration PRIVATE nlohmann_json::nlohmann_json)
 target_include_directories(DRAMSysConfiguration PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})
+
+target_link_libraries(DRAMSysConfiguration PRIVATE nlohmann_json::nlohmann_json)
diff --git a/DRAMSys/library/src/common/configuration/Configuration.cpp b/DRAMSys/library/src/common/configuration/Configuration.cpp
index 006db6f2..c610f579 100644
--- a/DRAMSys/library/src/common/configuration/Configuration.cpp
+++ b/DRAMSys/library/src/common/configuration/Configuration.cpp
@@ -34,7 +34,6 @@
  */
 
 #include "Configuration.h"
-#include "util.h"
 
 #include <fstream>
 
@@ -43,14 +42,11 @@ namespace DRAMSysConfiguration
 
 void to_json(json &j, const Configuration &c)
 {
-    j = json{{"addressmapping", c.addressMapping},
-             {"mcconfig", c.mcConfig},
-             {"memspec", c.memSpec},
-             {"simulationid", c.simulationId},
-             {"simconfig", c.simConfig}};
+    j = json{{"addressmapping", c.addressMapping}, {"mcconfig", c.mcConfig},   {"memspec", c.memSpec},
+             {"simulationid", c.simulationId},     {"simconfig", c.simConfig}, {"thermalconfig", c.thermalConfig},
+             {"tracesetup", c.traceSetup}};
 
-    from_optional("thermalconfig", j, c.thermalConfig);
-    from_optional("tracesetup", j, c.traceSetup);
+    remove_null_values(j);
 }
 
 void from_json(const json &j, Configuration &c)
@@ -61,8 +57,11 @@ void from_json(const json &j, Configuration &c)
     j.at("simulationid").get_to(c.simulationId);
     j.at("simconfig").get_to(c.simConfig);
 
-    get_optional("thermalconfig", j, c.thermalConfig);
-    get_optional("tracesetup", j, c.traceSetup);
+    if (j.contains("thermalconfig"))
+        j.at("thermalconfig").get_to(c.thermalConfig);
+
+    if (j.contains("tracesetup"))
+        j.at("tracesetup").get_to(c.traceSetup);
 }
 
 Configuration from_path(const std::string &path)
@@ -72,4 +71,4 @@ Configuration from_path(const std::string &path)
     return simulation.get<DRAMSysConfiguration::Configuration>();
 }
 
-} // namespace Configuration
+} // namespace DRAMSysConfiguration
diff --git a/DRAMSys/library/src/common/configuration/Configuration.h b/DRAMSys/library/src/common/configuration/Configuration.h
index 9385d13a..676036ec 100644
--- a/DRAMSys/library/src/common/configuration/Configuration.h
+++ b/DRAMSys/library/src/common/configuration/Configuration.h
@@ -33,8 +33,8 @@
  *    Derek Christ
  */
 
-#ifndef CONFIGURATION_H
-#define CONFIGURATION_H
+#ifndef DRAMSYSCONFIGURATION_CONFIGURATION_H
+#define DRAMSYSCONFIGURATION_CONFIGURATION_H
 
 #include "AddressMapping.h"
 #include "McConfig.h"
@@ -42,6 +42,7 @@
 #include "ThermalConfig.h"
 #include "TraceSetup.h"
 #include "memspec/MemSpec.h"
+#include "util.h"
 
 #include <memory>
 #include <nlohmann/json.hpp>
@@ -68,8 +69,8 @@ struct Configuration
     MemSpec memSpec;
     SimConfig simConfig;
     std::string simulationId;
-    std::pair<ThermalConfig, bool> thermalConfig;
-    std::pair<TraceSetup, bool> traceSetup;
+    Optional<ThermalConfig> thermalConfig;
+    Optional<TraceSetup> traceSetup;
 };
 
 void to_json(json &j, const Configuration &p);
@@ -77,6 +78,6 @@ void from_json(const json &j, Configuration &p);
 
 Configuration from_path(const std::string &path);
 
-} // namespace Configuration
+} // namespace DRAMSysConfiguration
 
-#endif // CONFIGURATION_H
+#endif // DRAMSYSCONFIGURATION_CONFIGURATION_H
diff --git a/DRAMSys/library/src/common/configuration/McConfig.cpp b/DRAMSys/library/src/common/configuration/McConfig.cpp
index daaf66d0..50684665 100644
--- a/DRAMSys/library/src/common/configuration/McConfig.cpp
+++ b/DRAMSys/library/src/common/configuration/McConfig.cpp
@@ -34,8 +34,7 @@
  */
 
 #include "McConfig.h"
-#include "util.h"
-
+#include <iostream>
 namespace DRAMSysConfiguration
 {
 
@@ -52,29 +51,64 @@ void to_json(json &j, const McConfig &c)
              {"RefreshMaxPulledin", c.refreshMaxPulledin},
              {"PowerDownPolicy", c.powerDownPolicy},
              {"Arbiter", c.arbiter},
-             {"MaxActiveTransactions", c.maxActiveTransactions}};
+             {"MaxActiveTransactions", c.maxActiveTransactions},
+             {"RefreshManagment", c.refreshManagement}};
 
-    from_optional("RefreshManagment", j, c.refreshManagement);
+    remove_null_values(j);
 }
 
 void from_json(const json &j, McConfig &c)
 {
     json j_mcconfig = get_config_json(j, mcConfigPath, "mcconfig");
 
-    j_mcconfig.at("PagePolicy").get_to(c.pagePolicy);
-    j_mcconfig.at("Scheduler").get_to(c.scheduler);
-    j_mcconfig.at("SchedulerBuffer").get_to(c.schedulerBuffer);
-    j_mcconfig.at("RequestBufferSize").get_to(c.requestBufferSize);
-    j_mcconfig.at("CmdMux").get_to(c.cmdMux);
-    j_mcconfig.at("RespQueue").get_to(c.respQueue);
-    j_mcconfig.at("RefreshPolicy").get_to(c.refreshPolicy);
-    j_mcconfig.at("RefreshMaxPostponed").get_to(c.refreshMaxPostponed);
-    j_mcconfig.at("RefreshMaxPulledin").get_to(c.refreshMaxPulledin);
-    j_mcconfig.at("PowerDownPolicy").get_to(c.powerDownPolicy);
-    j_mcconfig.at("Arbiter").get_to(c.arbiter);
-    j_mcconfig.at("MaxActiveTransactions").get_to(c.maxActiveTransactions);
+    if (j_mcconfig.contains("PagePolicy"))
+        j_mcconfig.at("PagePolicy").get_to(c.pagePolicy);
 
-    get_optional("RefreshManagment", j_mcconfig, c.refreshManagement);
+    if (j_mcconfig.contains("PagePolicy"))
+        j_mcconfig.at("Scheduler").get_to(c.scheduler);
+
+    if (j_mcconfig.contains("SchedulerBuffer"))
+        j_mcconfig.at("SchedulerBuffer").get_to(c.schedulerBuffer);
+
+    if (j_mcconfig.contains("RequestBufferSize"))
+        j_mcconfig.at("RequestBufferSize").get_to(c.requestBufferSize);
+
+    if (j_mcconfig.contains("CmdMux"))
+        j_mcconfig.at("CmdMux").get_to(c.cmdMux);
+
+    if (j_mcconfig.contains("RespQueue"))
+        j_mcconfig.at("RespQueue").get_to(c.respQueue);
+
+    if (j_mcconfig.contains("RefreshPolicy"))
+        j_mcconfig.at("RefreshPolicy").get_to(c.refreshPolicy);
+
+    if (j_mcconfig.contains("RefreshMaxPostponed"))
+        j_mcconfig.at("RefreshMaxPostponed").get_to(c.refreshMaxPostponed);
+
+    if (j_mcconfig.contains("RefreshMaxPulledin"))
+        j_mcconfig.at("RefreshMaxPulledin").get_to(c.refreshMaxPulledin);
+
+    if (j_mcconfig.contains("PowerDownPolicy"))
+        j_mcconfig.at("PowerDownPolicy").get_to(c.powerDownPolicy);
+
+    if (j_mcconfig.contains("Arbiter"))
+        j_mcconfig.at("Arbiter").get_to(c.arbiter);
+
+    if (j_mcconfig.contains("MaxActiveTransactions"))
+        j_mcconfig.at("MaxActiveTransactions").get_to(c.maxActiveTransactions);
+
+    if (j_mcconfig.contains("RefreshManagment"))
+        j_mcconfig.at("RefreshManagment").get_to(c.refreshManagement);
+
+    invalidateEnum(c.pagePolicy);
+    invalidateEnum(c.scheduler);
+    invalidateEnum(c.schedulerBuffer);
+    invalidateEnum(c.cmdMux);
+    invalidateEnum(c.respQueue);
+    invalidateEnum(c.refreshPolicy);
+    invalidateEnum(c.respQueue);
+    invalidateEnum(c.powerDownPolicy);
+    invalidateEnum(c.arbiter);
 }
 
-} // namespace Configuration
+} // namespace DRAMSysConfiguration
diff --git a/DRAMSys/library/src/common/configuration/McConfig.h b/DRAMSys/library/src/common/configuration/McConfig.h
index 363a06b8..649d81bb 100644
--- a/DRAMSys/library/src/common/configuration/McConfig.h
+++ b/DRAMSys/library/src/common/configuration/McConfig.h
@@ -33,8 +33,10 @@
  *    Derek Christ
  */
 
-#ifndef MCCONFIG_H
-#define MCCONFIG_H
+#ifndef DRAMSYSCONFIGURATION_MCCONFIG_H
+#define DRAMSYSCONFIGURATION_MCCONFIG_H
+
+#include "util.h"
 
 #include <memory>
 #include <nlohmann/json.hpp>
@@ -150,19 +152,19 @@ NLOHMANN_JSON_SERIALIZE_ENUM(Arbiter, {{Arbiter::Invalid, nullptr},
 
 struct McConfig
 {
-    PagePolicy pagePolicy;
-    Scheduler scheduler;
-    SchedulerBuffer schedulerBuffer;
-    unsigned int requestBufferSize;
-    CmdMux cmdMux;
-    RespQueue respQueue;
-    RefreshPolicy refreshPolicy;
-    unsigned int refreshMaxPostponed;
-    unsigned int refreshMaxPulledin;
-    PowerDownPolicy powerDownPolicy;
-    Arbiter arbiter;
-    unsigned int maxActiveTransactions;
-    std::pair<bool, bool> refreshManagement;
+    Optional<PagePolicy> pagePolicy;
+    Optional<Scheduler> scheduler;
+    Optional<SchedulerBuffer> schedulerBuffer;
+    Optional<unsigned int> requestBufferSize;
+    Optional<CmdMux> cmdMux;
+    Optional<RespQueue> respQueue;
+    Optional<RefreshPolicy> refreshPolicy;
+    Optional<unsigned int> refreshMaxPostponed;
+    Optional<unsigned int> refreshMaxPulledin;
+    Optional<PowerDownPolicy> powerDownPolicy;
+    Optional<Arbiter> arbiter;
+    Optional<unsigned int> maxActiveTransactions;
+    Optional<bool> refreshManagement;
 };
 
 void to_json(json &j, const McConfig &c);
diff --git a/DRAMSys/library/src/common/configuration/SimConfig.cpp b/DRAMSys/library/src/common/configuration/SimConfig.cpp
index 77903e0b..34cc41ef 100644
--- a/DRAMSys/library/src/common/configuration/SimConfig.cpp
+++ b/DRAMSys/library/src/common/configuration/SimConfig.cpp
@@ -34,7 +34,6 @@
  */
 
 #include "SimConfig.h"
-#include "util.h"
 
 namespace DRAMSysConfiguration
 {
@@ -62,21 +61,53 @@ void from_json(const json &j, SimConfig &c)
 {
     json j_simconfig = get_config_json(j, simConfigPath, "simconfig");
 
-    j_simconfig.at("AddressOffset").get_to(c.addressOffset);
-    j_simconfig.at("CheckTLM2Protocol").get_to(c.checkTLM2Protocol);
-    j_simconfig.at("DatabaseRecording").get_to(c.databaseRecording);
-    j_simconfig.at("Debug").get_to(c.debug);
-    j_simconfig.at("ECCControllerMode").get_to(c.eccControllerMode);
-    j_simconfig.at("EnableWindowing").get_to(c.enableWindowing);
-    j_simconfig.at("ErrorCSVFile").get_to(c.errorCsvFile);
-    j_simconfig.at("ErrorChipSeed").get_to(c.errorChipSeed);
-    j_simconfig.at("PowerAnalysis").get_to(c.powerAnalysis);
-    j_simconfig.at("SimulationName").get_to(c.simulationName);
-    j_simconfig.at("SimulationProgressBar").get_to(c.simulationProgressBar);
-    j_simconfig.at("StoreMode").get_to(c.storeMode);
-    j_simconfig.at("ThermalSimulation").get_to(c.thermalSimulation);
-    j_simconfig.at("UseMalloc").get_to(c.useMalloc);
-    j_simconfig.at("WindowSize").get_to(c.windowSize);
+    if (j_simconfig.contains("AddressOffset"))
+        j_simconfig.at("AddressOffset").get_to(c.addressOffset);
+
+    if (j_simconfig.contains("CheckTLM2Protocol"))
+        j_simconfig.at("CheckTLM2Protocol").get_to(c.checkTLM2Protocol);
+
+    if (j_simconfig.contains("DatabaseRecording"))
+        j_simconfig.at("DatabaseRecording").get_to(c.databaseRecording);
+
+    if (j_simconfig.contains("Debug"))
+        j_simconfig.at("Debug").get_to(c.debug);
+
+    if (j_simconfig.contains("ECCControllerMode"))
+        j_simconfig.at("ECCControllerMode").get_to(c.eccControllerMode);
+
+    if (j_simconfig.contains("EnableWindowing"))
+        j_simconfig.at("EnableWindowing").get_to(c.enableWindowing);
+
+    if (j_simconfig.contains("ErrorCSVFile"))
+        j_simconfig.at("ErrorCSVFile").get_to(c.errorCsvFile);
+
+    if (j_simconfig.contains("ErrorChipSeed"))
+        j_simconfig.at("ErrorChipSeed").get_to(c.errorChipSeed);
+
+    if (j_simconfig.contains("PowerAnalysis"))
+        j_simconfig.at("PowerAnalysis").get_to(c.powerAnalysis);
+
+    if (j_simconfig.contains("SimulationName"))
+        j_simconfig.at("SimulationName").get_to(c.simulationName);
+
+    if (j_simconfig.contains("SimulationProgressBar"))
+        j_simconfig.at("SimulationProgressBar").get_to(c.simulationProgressBar);
+
+    if (j_simconfig.contains("StoreMode"))
+        j_simconfig.at("StoreMode").get_to(c.storeMode);
+
+    if (j_simconfig.contains("ThermalSimulation"))
+        j_simconfig.at("ThermalSimulation").get_to(c.thermalSimulation);
+
+    if (j_simconfig.contains("UseMalloc"))
+        j_simconfig.at("UseMalloc").get_to(c.useMalloc);
+
+    if (j_simconfig.contains("WindowSize"))
+        j_simconfig.at("WindowSize").get_to(c.windowSize);
+
+    invalidateEnum(c.eccControllerMode);
+    invalidateEnum(c.storeMode);
 }
 
-} // namespace Configuration
+} // namespace DRAMSysConfiguration
diff --git a/DRAMSys/library/src/common/configuration/SimConfig.h b/DRAMSys/library/src/common/configuration/SimConfig.h
index b28d131d..d0ca2fa5 100644
--- a/DRAMSys/library/src/common/configuration/SimConfig.h
+++ b/DRAMSys/library/src/common/configuration/SimConfig.h
@@ -33,8 +33,10 @@
  *    Derek Christ
  */
 
-#ifndef SIMCONFIG_H
-#define SIMCONFIG_H
+#ifndef DRAMSYSCONFIGURATION_SIMCONFIG_H
+#define DRAMSYSCONFIGURATION_SIMCONFIG_H
+
+#include "util.h"
 
 #include <nlohmann/json.hpp>
 
@@ -64,26 +66,27 @@ enum class StoreMode
 };
 
 NLOHMANN_JSON_SERIALIZE_ENUM(StoreMode, {{StoreMode::Invalid, nullptr},
+                                         {StoreMode::NoStorage, "NoStorage"},
                                          {StoreMode::Store, "Store"},
                                          {StoreMode::ErrorModel, "ErrorModel"}})
 
 struct SimConfig
 {
-    unsigned int addressOffset;
-    bool checkTLM2Protocol;
-    bool databaseRecording;
-    bool debug;
-    ECCControllerMode eccControllerMode;
-    bool enableWindowing;
-    std::string errorCsvFile;
-    unsigned int errorChipSeed;
-    bool powerAnalysis;
-    std::string simulationName;
-    bool simulationProgressBar;
-    StoreMode storeMode;
-    bool thermalSimulation;
-    bool useMalloc;
-    unsigned int windowSize;
+    Optional<unsigned int> addressOffset;
+    Optional<bool> checkTLM2Protocol;
+    Optional<bool> databaseRecording;
+    Optional<bool> debug;
+    Optional<ECCControllerMode> eccControllerMode;
+    Optional<bool> enableWindowing;
+    Optional<std::string> errorCsvFile;
+    Optional<unsigned int> errorChipSeed;
+    Optional<bool> powerAnalysis;
+    Optional<std::string> simulationName;
+    Optional<bool> simulationProgressBar;
+    Optional<StoreMode> storeMode;
+    Optional<bool> thermalSimulation;
+    Optional<bool> useMalloc;
+    Optional<unsigned int> windowSize;
 };
 
 void to_json(json &j, const SimConfig &c);
diff --git a/DRAMSys/library/src/common/configuration/ThermalConfig.cpp b/DRAMSys/library/src/common/configuration/ThermalConfig.cpp
index 6c69daec..5ed4fa8f 100644
--- a/DRAMSys/library/src/common/configuration/ThermalConfig.cpp
+++ b/DRAMSys/library/src/common/configuration/ThermalConfig.cpp
@@ -100,4 +100,4 @@ void from_json(const json &j, PowerInfo &c)
     j_powerinfo.at("dram_die_channel3").get_to(c.channel3);
 }
 
-} // namespace Configuration
+} // namespace DRAMSysConfiguration
diff --git a/DRAMSys/library/src/common/configuration/ThermalConfig.h b/DRAMSys/library/src/common/configuration/ThermalConfig.h
index 02c905b6..b7ed3238 100644
--- a/DRAMSys/library/src/common/configuration/ThermalConfig.h
+++ b/DRAMSys/library/src/common/configuration/ThermalConfig.h
@@ -33,8 +33,8 @@
  *    Derek Christ
  */
 
-#ifndef THERMALCONFIG_H
-#define THERMALCONFIG_H
+#ifndef DRAMSYSCONFIGURATION_THERMALCONFIG_H
+#define DRAMSYSCONFIGURATION_THERMALCONFIG_H
 
 #include <nlohmann/json.hpp>
 
diff --git a/DRAMSys/library/src/common/configuration/TraceSetup.cpp b/DRAMSys/library/src/common/configuration/TraceSetup.cpp
index 39b76790..2b9f4615 100644
--- a/DRAMSys/library/src/common/configuration/TraceSetup.cpp
+++ b/DRAMSys/library/src/common/configuration/TraceSetup.cpp
@@ -34,7 +34,6 @@
  */
 
 #include "TraceSetup.h"
-#include "util.h"
 
 namespace DRAMSysConfiguration
 {
@@ -61,12 +60,11 @@ void to_json(json &j, const TraceSetup &c)
             inititator_j["numRequests"] = generator->numRequests;
             inititator_j["rwRatio"] = generator->rwRatio;
             inititator_j["addressDistribution"] = generator->addressDistribution;
-
-            from_optional("seed", inititator_j, generator->seed);
-            from_optional("maxPendingReadRequests", inititator_j, generator->maxPendingReadRequests);
-            from_optional("maxPendingWriteRequests", inititator_j, generator->maxPendingWriteRequests);
-            from_optional("minAddress", inititator_j, generator->minAddress);
-            from_optional("maxAddress", inititator_j, generator->maxAddress);
+            inititator_j["seed"] = generator->seed;
+            inititator_j["maxPendingReadRequests"] = generator->maxPendingReadRequests;
+            inititator_j["maxPendingWriteRequests"] = generator->maxPendingWriteRequests;
+            inititator_j["minAddress"] = generator->minAddress;
+            inititator_j["maxAddress"] = generator->maxAddress;
         }
         else if (const auto hammer = dynamic_cast<TraceHammer *>(initiator.get()))
         {
@@ -79,6 +77,7 @@ void to_json(json &j, const TraceSetup &c)
             inititator_j["type"] = "player";
         }
 
+        remove_null_values(inititator_j);
         j.insert(j.end(), inititator_j);
     }
 }
@@ -103,11 +102,20 @@ void from_json(const json &j, TraceSetup &c)
             initiator_j.at("rwRatio").get_to(generator->rwRatio);
             initiator_j.at("addressDistribution").get_to(generator->addressDistribution);
 
-            get_optional("seed", initiator_j, generator->seed);
-            get_optional("maxPendingReadRequests", initiator_j, generator->maxPendingReadRequests);
-            get_optional("maxPendingWriteRequests", initiator_j, generator->maxPendingWriteRequests);
-            get_optional("minAddress", initiator_j, generator->minAddress);
-            get_optional("maxAddress", initiator_j, generator->maxAddress);
+            if (initiator_j.contains("seed"))
+                initiator_j.at("seed").get_to(generator->seed);
+
+            if (initiator_j.contains("maxPendingReadRequests"))
+                initiator_j.at("maxPendingReadRequests").get_to(generator->maxPendingReadRequests);
+
+            if (initiator_j.contains("maxPendingWriteRequests"))
+                initiator_j.at("maxPendingWriteRequests").get_to(generator->maxPendingWriteRequests);
+
+            if (initiator_j.contains("minAddress"))
+                initiator_j.at("minAddress").get_to(generator->minAddress);
+
+            if (initiator_j.contains("maxAddress"))
+                initiator_j.at("maxAddress").get_to(generator->maxAddress);
 
             initiator = std::unique_ptr<TraceGenerator>(generator);
         }
@@ -128,4 +136,4 @@ void from_json(const json &j, TraceSetup &c)
     }
 }
 
-} // namespace Configuration
+} // namespace DRAMSysConfiguration
diff --git a/DRAMSys/library/src/common/configuration/TraceSetup.h b/DRAMSys/library/src/common/configuration/TraceSetup.h
index 61361bc2..6ac8156b 100644
--- a/DRAMSys/library/src/common/configuration/TraceSetup.h
+++ b/DRAMSys/library/src/common/configuration/TraceSetup.h
@@ -33,8 +33,10 @@
  *    Derek Christ
  */
 
-#ifndef TRACESETUP_H
-#define TRACESETUP_H
+#ifndef DRAMSYSCONFIGURATION_TRACESETUP_H
+#define DRAMSYSCONFIGURATION_TRACESETUP_H
+
+#include "util.h"
 
 #include <memory>
 #include <nlohmann/json.hpp>
@@ -85,12 +87,12 @@ struct TraceGenerator : public TrafficInitiator
     unsigned int numRequests;
     double rwRatio;
     AddressDistribution addressDistribution;
-    std::pair<unsigned int, bool> addressIncrement;
-    std::pair<unsigned int, bool> seed;
-    std::pair<unsigned int, bool> maxPendingReadRequests;
-    std::pair<unsigned int, bool> maxPendingWriteRequests;
-    std::pair<unsigned int, bool> minAddress;
-    std::pair<unsigned int, bool> maxAddress;
+    Optional<unsigned int> addressIncrement;
+    Optional<unsigned int> seed;
+    Optional<unsigned int> maxPendingReadRequests;
+    Optional<unsigned int> maxPendingWriteRequests;
+    Optional<unsigned int> minAddress;
+    Optional<unsigned int> maxAddress;
 };
 
 struct TraceHammer : public TrafficInitiator
@@ -101,7 +103,7 @@ struct TraceHammer : public TrafficInitiator
 
 struct TraceSetup
 {
-    std::unordered_set<std::unique_ptr<TrafficInitiator>> initiators;
+    std::unordered_set<std::shared_ptr<TrafficInitiator>> initiators;
 };
 
 void to_json(json &j, const TraceSetup &c);
diff --git a/DRAMSys/library/src/common/configuration/memspec/MemArchitectureSpec.h b/DRAMSys/library/src/common/configuration/memspec/MemArchitectureSpec.h
index 80a18ecc..6179e986 100644
--- a/DRAMSys/library/src/common/configuration/memspec/MemArchitectureSpec.h
+++ b/DRAMSys/library/src/common/configuration/memspec/MemArchitectureSpec.h
@@ -33,8 +33,8 @@
  *    Derek Christ
  */
 
-#ifndef MEMARCHITECTURESPEC_H
-#define MEMARCHITECTURESPEC_H
+#ifndef DRAMSYSCONFIGURATION_MEMARCHITECTURESPEC_H
+#define DRAMSYSCONFIGURATION_MEMARCHITECTURESPEC_H
 
 #include <nlohmann/json.hpp>
 #include <unordered_map>
diff --git a/DRAMSys/library/src/common/configuration/memspec/MemPowerSpec.h b/DRAMSys/library/src/common/configuration/memspec/MemPowerSpec.h
index 8d125a44..07c2da40 100644
--- a/DRAMSys/library/src/common/configuration/memspec/MemPowerSpec.h
+++ b/DRAMSys/library/src/common/configuration/memspec/MemPowerSpec.h
@@ -33,8 +33,8 @@
  *    Derek Christ
  */
 
-#ifndef MEMPOWERSPEC_H
-#define MEMPOWERSPEC_H
+#ifndef DRAMSYSCONFIGURATION_MEMPOWERSPEC_H
+#define DRAMSYSCONFIGURATION_MEMPOWERSPEC_H
 
 #include <nlohmann/json.hpp>
 #include <unordered_map>
diff --git a/DRAMSys/library/src/common/configuration/memspec/MemSpec.cpp b/DRAMSys/library/src/common/configuration/memspec/MemSpec.cpp
index 29def6d8..e4407cfb 100644
--- a/DRAMSys/library/src/common/configuration/memspec/MemSpec.cpp
+++ b/DRAMSys/library/src/common/configuration/memspec/MemSpec.cpp
@@ -34,7 +34,6 @@
  */
 
 #include "MemSpec.h"
-#include "util.h"
 
 namespace DRAMSysConfiguration
 {
@@ -44,9 +43,10 @@ void to_json(json &j, const MemSpec &c)
     j = json{{"memarchitecturespec", c.memArchitectureSpec},
              {"memoryId", c.memoryId},
              {"memoryType", c.memoryType},
-             {"memtimingspec", c.memTimingSpec}};
+             {"memtimingspec", c.memTimingSpec},
+             {"mempowerspec", c.memPowerSpec}};
 
-    from_optional("mempowerspec", j, c.memPowerSpec);
+    remove_null_values(j);
 }
 
 void from_json(const json &j, MemSpec &c)
@@ -58,7 +58,8 @@ void from_json(const json &j, MemSpec &c)
     j_memspecs.at("memoryType").get_to(c.memoryType);
     j_memspecs.at("memtimingspec").get_to(c.memTimingSpec);
 
-    get_optional("mempowerspec", j, c.memPowerSpec);
+    if (j_memspecs.contains("mempowerspec"))
+        j_memspecs.at("mempowerspec").get_to(c.memPowerSpec);
 }
 
 } // namespace Configuration
diff --git a/DRAMSys/library/src/common/configuration/memspec/MemSpec.h b/DRAMSys/library/src/common/configuration/memspec/MemSpec.h
index 248709b4..30568d0d 100644
--- a/DRAMSys/library/src/common/configuration/memspec/MemSpec.h
+++ b/DRAMSys/library/src/common/configuration/memspec/MemSpec.h
@@ -33,12 +33,13 @@
  *    Derek Christ
  */
 
-#ifndef MEMSPEC_H
-#define MEMSPEC_H
+#ifndef DRAMSYSCONFIGURATION_MEMSPEC_H
+#define DRAMSYSCONFIGURATION_MEMSPEC_H
 
 #include "MemArchitectureSpec.h"
 #include "MemPowerSpec.h"
 #include "MemTimingSpec.h"
+#include "util.h"
 
 #include <nlohmann/json.hpp>
 
@@ -54,7 +55,7 @@ struct MemSpec
     std::string memoryId;
     std::string memoryType;
     MemTimingSpec memTimingSpec;
-    std::pair<MemPowerSpec, bool> memPowerSpec;
+    Optional<MemPowerSpec> memPowerSpec;
 };
 
 void to_json(json &j, const MemSpec &c);
diff --git a/DRAMSys/library/src/common/configuration/memspec/MemTimingSpec.h b/DRAMSys/library/src/common/configuration/memspec/MemTimingSpec.h
index 61ba7308..d06898be 100644
--- a/DRAMSys/library/src/common/configuration/memspec/MemTimingSpec.h
+++ b/DRAMSys/library/src/common/configuration/memspec/MemTimingSpec.h
@@ -33,8 +33,8 @@
  *    Derek Christ
  */
 
-#ifndef MEMTIMINGSPEC_H
-#define MEMTIMINGSPEC_H
+#ifndef DRAMSYSCONFIGURATION_MEMTIMINGSPEC_H
+#define DRAMSYSCONFIGURATION_MEMTIMINGSPEC_H
 
 #include <nlohmann/json.hpp>
 #include <unordered_map>
diff --git a/DRAMSys/library/src/common/configuration/tests/simpletest.cpp b/DRAMSys/library/src/common/configuration/tests/simpletest.cpp
index 1be7c5e5..9a4ce6a3 100644
--- a/DRAMSys/library/src/common/configuration/tests/simpletest.cpp
+++ b/DRAMSys/library/src/common/configuration/tests/simpletest.cpp
@@ -6,13 +6,13 @@ using json = nlohmann::json;
 
 DRAMSysConfiguration::AddressMapping getAddressMapping()
 {
-    return DRAMSysConfiguration::AddressMapping{{{0, 1}, true},
+    return DRAMSysConfiguration::AddressMapping{{{0, 1}},
                                                 {2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12},
                                                 {16},
-                                                {{13, 14, 15}, true},
+                                                {{13, 14, 15}},
                                                 {17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32},
-                                                {{33}, true},
-                                                {{}, false}};
+                                                {{33}},
+                                                {{}}};
 }
 
 DRAMSysConfiguration::McConfig getMcConfig()
@@ -29,14 +29,14 @@ DRAMSysConfiguration::McConfig getMcConfig()
                                           DRAMSysConfiguration::PowerDownPolicy::NoPowerDown,
                                           DRAMSysConfiguration::Arbiter::Simple,
                                           128,
-                                          std::pair<bool, bool>{false, true}};
+                                          {}};
 }
 
 DRAMSysConfiguration::SimConfig getSimConfig()
 {
     return DRAMSysConfiguration::SimConfig{
-        0,   false, true,   false, DRAMSysConfiguration::ECCControllerMode::Disabled, false, "error.csv",
-        42,  false, "ddr5", true,  DRAMSysConfiguration::StoreMode::NoStorage,        false, false,
+        0,   false, true,     false, DRAMSysConfiguration::ECCControllerMode::Disabled, false, {"error.csv"},
+        42,  false, {"ddr5"}, true,  DRAMSysConfiguration::StoreMode::NoStorage,        false, false,
         1000};
 }
 
@@ -74,10 +74,10 @@ std::unique_ptr<DRAMSysConfiguration::TraceGenerator> getTraceGeneratorRandom()
     gen->name = "MyTestGen";
 
     gen->addressDistribution = DRAMSysConfiguration::AddressDistribution::Random;
-    gen->maxAddress = {1000, true};
-    gen->maxPendingReadRequests = {8, true};
+    gen->maxAddress = 1000;
+    gen->maxPendingReadRequests = 8;
     gen->rwRatio = 0.5;
-    gen->seed = {1337, true};
+    gen->seed = 1337;
     gen->numRequests = 1000;
 
     return std::unique_ptr<DRAMSysConfiguration::TraceGenerator>(gen);
@@ -91,9 +91,9 @@ std::unique_ptr<DRAMSysConfiguration::TraceGenerator> getTraceGeneratorSequentia
     gen->name = "MyTestGen";
 
     gen->addressDistribution = DRAMSysConfiguration::AddressDistribution::Sequential;
-    gen->addressIncrement = {64, true};
-    gen->maxAddress = {1000, true};
-    gen->maxPendingReadRequests = {8, true};
+    gen->addressIncrement = 64;
+    gen->maxAddress = 1000;
+    gen->maxPendingReadRequests = 8;
     gen->rwRatio = 0.5;
     gen->numRequests = 1000;
 
@@ -115,13 +115,13 @@ std::unique_ptr<DRAMSysConfiguration::TraceHammer> getTraceHammer()
 
 DRAMSysConfiguration::TraceSetup getTraceSetup()
 {
-    std::unordered_set<std::unique_ptr<DRAMSysConfiguration::TrafficInitiator>> initiators;
+    std::unordered_set<std::shared_ptr<DRAMSysConfiguration::TrafficInitiator>> initiators;
     initiators.emplace(getTracePlayer());
     initiators.emplace(getTraceGeneratorRandom());
     initiators.emplace(getTraceGeneratorSequential());
     initiators.emplace(getTraceHammer());
 
-    return DRAMSysConfiguration::TraceSetup{std::move(initiators)};
+    return DRAMSysConfiguration::TraceSetup{initiators};
 }
 
 DRAMSysConfiguration::Configuration getConfig(const DRAMSysConfiguration::MemSpec &memSpec)
@@ -132,9 +132,9 @@ DRAMSysConfiguration::Configuration getConfig(const DRAMSysConfiguration::MemSpe
         memSpec,
         getSimConfig(),
         "std::string_simulationId",
-        {getThermalConfig(), true},
+        getThermalConfig(),
         // {{}, false}, works too
-        {getTraceSetup(), true},
+        getTraceSetup(),
     };
 }
 
diff --git a/DRAMSys/library/src/common/configuration/util.h b/DRAMSys/library/src/common/configuration/util.h
index 113c3265..c6090fa3 100644
--- a/DRAMSys/library/src/common/configuration/util.h
+++ b/DRAMSys/library/src/common/configuration/util.h
@@ -33,8 +33,8 @@
  *    Derek Christ
  */
 
-#ifndef UTIL_H
-#define UTIL_H
+#ifndef DRAMSYSCONFIGURATION_UTIL_H
+#define DRAMSYSCONFIGURATION_UTIL_H
 
 #include <nlohmann/json.hpp>
 #include <utility>
@@ -43,35 +43,91 @@ namespace DRAMSysConfiguration
 {
 using json = nlohmann::json;
 
-/**
- * Inspired from https://github.com/nlohmann/json/issues/1749#issuecomment-770748811
- */
 template <typename T>
-void get_optional(const std::string &name, const json &j, std::pair<T, bool> &val)
+class Optional : public std::pair<T, bool>
 {
-    auto it = j.find(name);
-    if (it != j.end())
+public:
+    Optional() : std::pair<T, bool>{{}, false}
     {
-        val.first = it->template get<T>();
-        val.second = true;
     }
-    else
+    Optional(const T &v) : std::pair<T, bool>{v, true}
     {
-        val.second = false;
     }
-}
+
+    bool isValid() const
+    {
+        return this->second;
+    }
+
+    const T &getValue() const
+    {
+        assert(this->second == true);
+        return this->first;
+    }
+
+    void setValue(const T &v)
+    {
+        this->first = v;
+        this->second = true;
+    }
+
+    void invalidate()
+    {
+        this->second = false;
+    }
+};
 
 template <typename T>
-void from_optional(const std::string &name, json &j, const std::pair<T, bool> &val)
+void invalidateEnum(T &value)
 {
-    if (val.second)
-    {
-        j[name] = val.first;
-    }
+    if (value.isValid() && value.getValue() == T::first_type::Invalid)
+        value.invalidate();
 }
 
 json get_config_json(const json &j, const std::string &configPath, const std::string &objectName);
 
+inline void remove_null_values(json &j)
+{
+    std::vector<std::string> keysToRemove;
+
+    for (const auto &element : j.items())
+    {
+        if (element.value() == nullptr)
+            keysToRemove.emplace_back(element.key());
+    }
+
+    std::for_each(keysToRemove.begin(), keysToRemove.end(), [&](const std::string &key) { j.erase(key); });
+}
+
 } // namespace DRAMSysConfiguration
 
+/**
+ * Inspired from
+ * https://json.nlohmann.me/features/arbitrary_types/#how-can-i-use-get-for-non-default-constructiblenon-copyable-types
+ */
+namespace nlohmann
+{
+
+template <typename T>
+void to_json(nlohmann::json &j, const DRAMSysConfiguration::Optional<T> &v)
+{
+    if (v.isValid())
+        j = v.getValue();
+    else
+        j = nullptr;
+}
+
+template <typename T>
+void from_json(const nlohmann::json &j, DRAMSysConfiguration::Optional<T> &v)
+{
+    if (j.is_null())
+        v = {};
+    else
+    {
+        v = {j.get<T>()};
+    }
+}
+
+} // namespace nlohmann
+
 #endif