diff --git a/src/handles/delete-handle.cpp b/src/handles/delete-handle.cpp
index d062399..5c06015 100644
--- a/src/handles/delete-handle.cpp
+++ b/src/handles/delete-handle.cpp
@@ -1,5 +1,5 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
+/*
  * Copyright (c) 2014-2017, Regents of the University of California.
  *
  * This file is part of NDN repo-ng (Next generation of NDN repository).
@@ -33,48 +33,47 @@
 DeleteHandle::onInterest(const Name& prefix, const Interest& interest)
 {
   m_validator.validate(interest, bind(&DeleteHandle::onValidated, this, _1, prefix),
-                       bind(&DeleteHandle::onValidationFailed, this, _1, _2));
+                                 bind(&DeleteHandle::onValidationFailed, this, _1, _2));
 }
 
 void
-DeleteHandle::onValidated(const shared_ptr<const Interest>& interest, const Name& prefix)
+DeleteHandle::onValidated(const Interest& interest, const Name& prefix)
 {
   RepoCommandParameter parameter;
 
   try {
-    extractParameter(*interest, prefix, parameter);
+    extractParameter(interest, prefix, parameter);
   }
   catch (RepoCommandParameter::Error) {
-    negativeReply(*interest, 403);
+    negativeReply(interest, 403);
     return;
   }
 
   if (parameter.hasSelectors()) {
 
     if (parameter.hasStartBlockId() || parameter.hasEndBlockId()) {
-      negativeReply(*interest, 402);
+      negativeReply(interest, 402);
       return;
     }
 
     //choose data with selector and delete it
-    processSelectorDeleteCommand(*interest, parameter);
+    processSelectorDeleteCommand(interest, parameter);
     return;
   }
 
   if (!parameter.hasStartBlockId() && !parameter.hasEndBlockId()) {
-    processSingleDeleteCommand(*interest, parameter);
+    processSingleDeleteCommand(interest, parameter);
     return;
   }
 
-  processSegmentDeleteCommand(*interest, parameter);
+  processSegmentDeleteCommand(interest, parameter);
 }
 
 void
-DeleteHandle::onValidationFailed(const shared_ptr<const Interest>& interest,
-                                 const std::string& reason)
+DeleteHandle::onValidationFailed(const Interest& interest, const ValidationError& error)
 {
-  std::cerr << reason << std::endl;
-  negativeReply(*interest, 401);
+  std::cerr << error << std::endl;
+  negativeReply(interest, 401);
 }
 //listen change the setinterestfilter
 void
diff --git a/src/handles/delete-handle.hpp b/src/handles/delete-handle.hpp
index 265d5ef..17cb48a 100644
--- a/src/handles/delete-handle.hpp
+++ b/src/handles/delete-handle.hpp
@@ -1,5 +1,5 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
+/*
  * Copyright (c) 2014-2017, Regents of the University of California.
  *
  * This file is part of NDN repo-ng (Next generation of NDN repository).
@@ -50,10 +50,10 @@
   onInterest(const Name& prefix, const Interest& interest);
 
   void
-  onValidated(const std::shared_ptr<const Interest>& interest, const Name& prefix);
+  onValidated(const Interest& interest, const Name& prefix);
 
   void
-  onValidationFailed(const std::shared_ptr<const Interest>& interest, const std::string& reason);
+  onValidationFailed(const Interest& interest, const ValidationError& error);
 
   /**
    * @todo delete check has not been realized due to the while loop of segmented data deletion.
diff --git a/src/handles/watch-handle.cpp b/src/handles/watch-handle.cpp
index 91eaac4..bee036f 100644
--- a/src/handles/watch-handle.cpp
+++ b/src/handles/watch-handle.cpp
@@ -1,5 +1,5 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
+/*
  * Copyright (c) 2014-2017, Regents of the University of California.
  *
  * This file is part of NDN repo-ng (Next generation of NDN repository).
@@ -53,18 +53,18 @@
 }
 
 void
-WatchHandle::onValidated(const shared_ptr<const Interest>& interest, const Name& prefix)
+WatchHandle::onValidated(const Interest& interest, const Name& prefix)
 {
   RepoCommandParameter parameter;
   try {
-    extractParameter(*interest, prefix, parameter);
+    extractParameter(interest, prefix, parameter);
   }
   catch (RepoCommandParameter::Error) {
-    negativeReply(*interest, 403);
+    negativeReply(interest, 403);
     return;
   }
 
-  processWatchCommand(*interest, parameter);
+  processWatchCommand(interest, parameter);
 }
 
 void WatchHandle::watchStop(const Name& name)
@@ -79,11 +79,10 @@
 }
 
 void
-WatchHandle::onValidationFailed(const shared_ptr<const Interest>& interest,
-                                const std::string& reason)
+WatchHandle::onValidationFailed(const Interest& interest, const ValidationError& error)
 {
-  std::cerr << reason << std::endl;
-  negativeReply(*interest, 401);
+  std::cerr << error << std::endl;
+  negativeReply(interest, 401);
 }
 
 void
@@ -95,13 +94,12 @@
 }
 
 void
-WatchHandle::onDataValidated(const Interest& interest, const shared_ptr<const Data>& data,
-                             const Name& name)
+WatchHandle::onDataValidated(const Interest& interest, const Data& data, const Name& name)
 {
   if (!m_processes[name].second) {
     return;
   }
-  if (getStorageHandle().insertData(*data)) {
+  if (getStorageHandle().insertData(data)) {
     m_size++;
     if (!onRunning(name))
       return;
@@ -113,7 +111,7 @@
 
     // update selectors
     // if data name is equal to interest name, use MinSuffixComponents selecor to exclude this data
-    if (data->getName().size() == interest.getName().size()) {
+    if (data.getName().size() == interest.getName().size()) {
       fetchInterest.setMinSuffixComponents(2);
     }
     else {
@@ -122,7 +120,7 @@
         exclude = interest.getExclude();
       }
 
-      exclude.excludeBefore(data->getName()[interest.getName().size()]);
+      exclude.excludeBefore(data.getName()[interest.getName().size()]);
       fetchInterest.setExclude(exclude);
     }
 
@@ -139,10 +137,10 @@
 }
 
 void
-WatchHandle::onDataValidationFailed(const Interest& interest, const shared_ptr<const Data>& data,
-                                    const std::string& reason, const Name& name)
+WatchHandle::onDataValidationFailed(const Interest& interest, const Data& data,
+                                    const ValidationError& error, const Name& name)
 {
-  std::cerr << reason << std::endl;
+  std::cerr << error << std::endl;
   if (!m_processes[name].second) {
     return;
   }
@@ -156,7 +154,7 @@
 
   // update selectors
   // if data name is equal to interest name, use MinSuffixComponents selecor to exclude this data
-  if (data->getName().size() == interest.getName().size()) {
+  if (data.getName().size() == interest.getName().size()) {
     fetchInterest.setMinSuffixComponents(2);
   }
   else {
@@ -165,7 +163,7 @@
       exclude = interest.getExclude();
     }
     // Only exclude this data since other data whose names are smaller may be validated and satisfied
-    exclude.excludeBefore(data->getName()[interest.getName().size()]);
+    exclude.excludeBefore(data.getName()[interest.getName().size()]);
     fetchInterest.setExclude(exclude);
   }
 
@@ -219,27 +217,26 @@
 }
 
 void
-WatchHandle::onStopValidated(const shared_ptr<const Interest>& interest, const Name& prefix)
+WatchHandle::onStopValidated(const Interest& interest, const Name& prefix)
 {
   RepoCommandParameter parameter;
   try {
-    extractParameter(*interest, prefix, parameter);
+    extractParameter(interest, prefix, parameter);
   }
   catch (RepoCommandParameter::Error) {
-    negativeReply(*interest, 403);
+    negativeReply(interest, 403);
     return;
   }
 
   watchStop(parameter.getName());
-  negativeReply(*interest, 101);
+  negativeReply(interest, 101);
 }
 
 void
-WatchHandle::onStopValidationFailed(const shared_ptr<const Interest>& interest,
-                                    const std::string& reason)
+WatchHandle::onStopValidationFailed(const Interest& interest, const ValidationError& error)
 {
-  std::cerr << reason << std::endl;
-  negativeReply(*interest, 401);
+  std::cerr << error << std::endl;
+  negativeReply(interest, 401);
 }
 
 void
@@ -251,26 +248,26 @@
 }
 
 void
-WatchHandle::onCheckValidated(const shared_ptr<const Interest>& interest, const Name& prefix)
+WatchHandle::onCheckValidated(const Interest& interest, const Name& prefix)
 {
   RepoCommandParameter parameter;
   try {
-    extractParameter(*interest, prefix, parameter);
+    extractParameter(interest, prefix, parameter);
   }
   catch (RepoCommandParameter::Error) {
-    negativeReply(*interest, 403);
+    negativeReply(interest, 403);
     return;
   }
 
   if (!parameter.hasName()) {
-    negativeReply(*interest, 403);
+    negativeReply(interest, 403);
     return;
   }
   //check whether this process exists
   Name name = parameter.getName();
   if (m_processes.count(name) == 0) {
     std::cerr << "no such process name: " << name << std::endl;
-    negativeReply(*interest, 404);
+    negativeReply(interest, 404);
     return;
   }
 
@@ -279,16 +276,15 @@
     response.setStatusCode(101);
   }
 
-  reply(*interest, response);
+  reply(interest, response);
 
 }
 
 void
-WatchHandle::onCheckValidationFailed(const shared_ptr<const Interest>& interest,
-                                     const std::string& reason)
+WatchHandle::onCheckValidationFailed(const Interest& interest, const ValidationError& error)
 {
-  std::cerr << reason << std::endl;
-  negativeReply(*interest, 401);
+  std::cerr << error << std::endl;
+  negativeReply(interest, 401);
 }
 
 void
diff --git a/src/handles/watch-handle.hpp b/src/handles/watch-handle.hpp
index 5768e06..c7071df 100644
--- a/src/handles/watch-handle.hpp
+++ b/src/handles/watch-handle.hpp
@@ -1,5 +1,5 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
+/*
  * Copyright (c) 2014-2017, Regents of the University of California.
  *
  * This file is part of NDN repo-ng (Next generation of NDN repository).
@@ -68,10 +68,10 @@
   onInterest(const Name& prefix, const Interest& interest);
 
   void
-  onValidated(const std::shared_ptr<const Interest>& interest, const Name& prefix);
+  onValidated(const Interest& interest, const Name& prefix);
 
   void
-  onValidationFailed(const std::shared_ptr<const Interest>& interest, const std::string& reason);
+  onValidationFailed(const Interest& interest, const ValidationError& error);
 
 private: // data fetching
   /**
@@ -87,15 +87,14 @@
   onTimeout(const Interest& interest, const Name& name);
 
   void
-  onDataValidated(const Interest& interest, const std::shared_ptr<const Data>& data,
-                  const Name& name);
+  onDataValidated(const Interest& interest, const Data& data, const Name& name);
 
   /**
    * @brief failure of validation
    */
   void
-  onDataValidationFailed(const Interest& interest, const std::shared_ptr<const Data>& data,
-                         const std::string& reason, const Name& name);
+  onDataValidationFailed(const Interest& interest, const Data& data,
+                         const ValidationError& error, const Name& name);
 
 
   void
@@ -112,11 +111,10 @@
   onCheckInterest(const Name& prefix, const Interest& interest);
 
   void
-  onCheckValidated(const std::shared_ptr<const Interest>& interest, const Name& prefix);
+  onCheckValidated(const Interest& interest, const Name& prefix);
 
   void
-  onCheckValidationFailed(const std::shared_ptr<const Interest>& interest,
-                          const std::string& reason);
+  onCheckValidationFailed(const Interest& interest, const ValidationError& error);
 
 private: // watch stop command
   /**
@@ -126,11 +124,10 @@
   onStopInterest(const Name& prefix, const Interest& interest);
 
   void
-  onStopValidated(const std::shared_ptr<const Interest>& interest, const Name& prefix);
+  onStopValidated(const Interest& interest, const Name& prefix);
 
   void
-  onStopValidationFailed(const std::shared_ptr<const Interest>& interest,
-                         const std::string& reason);
+  onStopValidationFailed(const Interest& interest, const ValidationError& error);
 
 private:
   void
diff --git a/src/handles/write-handle.cpp b/src/handles/write-handle.cpp
index a398f0b..4586bad 100644
--- a/src/handles/write-handle.cpp
+++ b/src/handles/write-handle.cpp
@@ -1,5 +1,5 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
+/*
  * Copyright (c) 2014-2017, Regents of the University of California.
  *
  * This file is part of NDN repo-ng (Next generation of NDN repository).
@@ -55,38 +55,37 @@
 }
 
 void
-WriteHandle::onValidated(const std::shared_ptr<const Interest>& interest, const Name& prefix)
+WriteHandle::onValidated(const Interest& interest, const Name& prefix)
 {
   //m_validResult = 1;
   RepoCommandParameter parameter;
   try {
-    extractParameter(*interest, prefix, parameter);
+    extractParameter(interest, prefix, parameter);
   }
   catch (RepoCommandParameter::Error) {
-    negativeReply(*interest, 403);
+    negativeReply(interest, 403);
     return;
   }
 
   if (parameter.hasStartBlockId() || parameter.hasEndBlockId()) {
     if (parameter.hasSelectors()) {
-      negativeReply(*interest, 402);
+      negativeReply(interest, 402);
       return;
     }
-    processSegmentedInsertCommand(*interest, parameter);
+    processSegmentedInsertCommand(interest, parameter);
   }
   else {
-    processSingleInsertCommand(*interest, parameter);
+    processSingleInsertCommand(interest, parameter);
   }
   if (parameter.hasInterestLifetime())
     m_interestLifetime = parameter.getInterestLifetime();
 }
 
 void
-WriteHandle::onValidationFailed(const std::shared_ptr<const Interest>& interest,
-                                const std::string& reason)
+WriteHandle::onValidationFailed(const Interest& interest, const ValidationError& error)
 {
-  std::cerr << reason << std::endl;
-  negativeReply(*interest, 401);
+  std::cerr << error << std::endl;
+  negativeReply(interest, 401);
 }
 
 void
@@ -98,9 +97,7 @@
 }
 
 void
-WriteHandle::onDataValidated(const Interest& interest,
-                             const std::shared_ptr<const Data>& data,
-                             ProcessId processId)
+WriteHandle::onDataValidated(const Interest& interest, const Data& data, ProcessId processId)
 {
   if (m_processes.count(processId) == 0) {
     return;
@@ -110,9 +107,9 @@
   RepoCommandResponse& response = process.response;
 
   if (response.getInsertNum() == 0) {
-    getStorageHandle().insertData(*data);
-   // getStorageHandle().insertEntry(*data);
-   // getStoreIndex().insert(*data);
+    getStorageHandle().insertData(data);
+   // getStorageHandle().insertEntry(data);
+   // getStoreIndex().insert(data);
     response.setInsertNum(1);
   }
 
@@ -120,10 +117,9 @@
 }
 
 void
-WriteHandle::onDataValidationFailed(const std::shared_ptr<const Data>& data,
-                                    const std::string& reason)
+WriteHandle::onDataValidationFailed(const Data& data, const ValidationError& error)
 {
-  std::cerr << reason << std::endl;
+  std::cerr << error << std::endl;
 }
 
 void
@@ -135,9 +131,7 @@
 }
 
 void
-WriteHandle::onSegmentDataValidated(const Interest& interest,
-                                    const std::shared_ptr<const Data>& data,
-                                    ProcessId processId)
+WriteHandle::onSegmentDataValidated(const Interest& interest, const Data& data, ProcessId processId)
 {
   if (m_processes.count(processId) == 0) {
     return;
@@ -145,7 +139,7 @@
   RepoCommandResponse& response = m_processes[processId].response;
 
   //refresh endBlockId
-  Name::Component finalBlockId = data->getFinalBlockId();
+  Name::Component finalBlockId = data.getFinalBlockId();
 
   if (!finalBlockId.empty()) {
     SegmentNo final = finalBlockId.toSegment();
@@ -160,7 +154,7 @@
   }
 
   //insert data
-  if (getStorageHandle().insertData(*data)) {
+  if (getStorageHandle().insertData(data)) {
     response.setInsertNum(response.getInsertNum() + 1);
   }
 
@@ -386,26 +380,26 @@
 }
 
 void
-WriteHandle::onCheckValidated(const shared_ptr<const Interest>& interest, const Name& prefix)
+WriteHandle::onCheckValidated(const Interest& interest, const Name& prefix)
 {
   RepoCommandParameter parameter;
   try {
-    extractParameter(*interest, prefix, parameter);
+    extractParameter(interest, prefix, parameter);
   }
   catch (RepoCommandParameter::Error) {
-    negativeReply(*interest, 403);
+    negativeReply(interest, 403);
     return;
   }
 
   if (!parameter.hasProcessId()) {
-    negativeReply(*interest, 403);
+    negativeReply(interest, 403);
     return;
   }
   //check whether this process exists
   ProcessId processId = parameter.getProcessId();
   if (m_processes.count(processId) == 0) {
     std::cerr << "no such processId: " << processId << std::endl;
-    negativeReply(*interest, 404);
+    negativeReply(interest, 404);
     return;
   }
 
@@ -416,27 +410,26 @@
   //Check whether it is single data fetching
   if (!response.hasStartBlockId() &&
       !response.hasEndBlockId()) {
-    reply(*interest, response);
+    reply(interest, response);
     return;
   }
 
   //read if noEndtimeout
   if (!response.hasEndBlockId()) {
     extendNoEndTime(process);
-    reply(*interest, response);
+    reply(interest, response);
     return;
   }
   else {
-    reply(*interest, response);
+    reply(interest, response);
   }
 }
 
 void
-WriteHandle::onCheckValidationFailed(const shared_ptr<const Interest>& interest,
-                                     const std::string& reason)
+WriteHandle::onCheckValidationFailed(const Interest& interest, const ValidationError& error)
 {
-  std::cerr << reason << std::endl;
-  negativeReply(*interest, 401);
+  std::cerr << error << std::endl;
+  negativeReply(interest, 401);
 }
 
 void
diff --git a/src/handles/write-handle.hpp b/src/handles/write-handle.hpp
index 1e7a007..c6622d9 100644
--- a/src/handles/write-handle.hpp
+++ b/src/handles/write-handle.hpp
@@ -1,5 +1,5 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
+/*
  * Copyright (c) 2014-2017, Regents of the University of California.
  *
  * This file is part of NDN repo-ng (Next generation of NDN repository).
@@ -107,10 +107,10 @@
   onInterest(const Name& prefix, const Interest& interest);
 
   void
-  onValidated(const std::shared_ptr<const Interest>& interest, const Name& prefix);
+  onValidated(const Interest& interest, const Name& prefix);
 
   void
-  onValidationFailed(const std::shared_ptr<const Interest>& interest, const std::string& reason);
+  onValidationFailed(const Interest& interest, const ValidationError& error);
 
 private: // single data fetching
   /**
@@ -120,8 +120,7 @@
   onData(const Interest& interest, const Data& data, ProcessId processId);
 
   void
-  onDataValidated(const Interest& interest, const std::shared_ptr<const Data>& data,
-                  ProcessId processId);
+  onDataValidated(const Interest& interest, const Data& data, ProcessId processId);
 
   /**
    * @brief handle when fetching one data timeout
@@ -140,8 +139,7 @@
   onSegmentData(const Interest& interest, const Data& data, ProcessId processId);
 
   void
-  onSegmentDataValidated(const Interest& interest, const std::shared_ptr<const Data>& data,
-                         ProcessId processId);
+  onSegmentDataValidated(const Interest& interest, const Data& data, ProcessId processId);
 
   /**
    * @brief Timeout when fetching segmented data. Data can be fetched RETRY_TIMEOUT times.
@@ -175,7 +173,7 @@
    * @brief failure of validation for both one or segmented data
    */
   void
-  onDataValidationFailed(const std::shared_ptr<const Data>& data, const std::string& reason);
+  onDataValidationFailed(const Data& data, const ValidationError& error);
 
   /**
    * @brief extends noEndTime of process if not noEndTimeout, set StatusCode 405
@@ -194,11 +192,10 @@
   onCheckInterest(const Name& prefix, const Interest& interest);
 
   void
-  onCheckValidated(const std::shared_ptr<const Interest>& interest, const Name& prefix);
+  onCheckValidated(const Interest& interest, const Name& prefix);
 
   void
-  onCheckValidationFailed(const std::shared_ptr<const Interest>& interest,
-                          const std::string& reason);
+  onCheckValidationFailed(const Interest& interest, const ValidationError& error);
 
 private:
   void