Refactoring, moving and renaming the NetworkActionPredictor.

chrome/browser/predictors/autocomplete_action_predictor.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "chrome/browser/autocomplete/network_action_predictor.h"
+#include "chrome/browser/predictors/autocomplete_action_predictor.h"
 
 #include <math.h>
 
 #include <vector>
 
 #include "base/bind.h"
 #include "base/i18n/case_conversion.h"
 #include "base/metrics/histogram.h"
 #include "base/string_util.h"
 #include "base/stringprintf.h"
 #include "base/utf_string_conversions.h"
 #include "chrome/browser/autocomplete/autocomplete.h"
 #include "chrome/browser/autocomplete/autocomplete_match.h"
-#include "chrome/browser/autocomplete/network_action_predictor_database.h"
 #include "chrome/browser/history/history.h"
 #include "chrome/browser/history/history_notifications.h"
 #include "chrome/browser/history/in_memory_database.h"
+#include "chrome/browser/predictors/predictor_database.h"
+#include "chrome/browser/predictors/predictor_database_factory.h"
 #include "chrome/browser/prerender/prerender_field_trial.h"
 #include "chrome/browser/prerender/prerender_manager.h"
 #include "chrome/browser/prerender/prerender_manager_factory.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/common/chrome_notification_types.h"
 #include "chrome/common/guid.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/notification_details.h"
 #include "content/public/browser/notification_service.h"
 #include "content/public/browser/notification_source.h"
 
 namespace {
 
 const float kConfidenceCutoff[] = {
   0.8f,
   0.5f
 };
 
 const size_t kMinimumUserTextLength = 1;
 const int kMinimumNumberOfHits = 3;
 
 COMPILE_ASSERT(arraysize(kConfidenceCutoff) ==
-               NetworkActionPredictor::LAST_PREDICT_ACTION,
+               predictors::AutocompleteActionPredictor::LAST_PREDICT_ACTION,
                ConfidenceCutoff_count_mismatch);
 
 enum DatabaseAction {
   DATABASE_ACTION_ADD,
   DATABASE_ACTION_UPDATE,
   DATABASE_ACTION_DELETE_SOME,
   DATABASE_ACTION_DELETE_ALL,
   DATABASE_ACTION_COUNT
 };
 
 bool IsAutocompleteMatchSearchType(const AutocompleteMatch& match) {
   switch (match.type) {
     // Matches using the user's default search engine.
     case AutocompleteMatch::SEARCH_WHAT_YOU_TYPED:
     case AutocompleteMatch::SEARCH_HISTORY:
     case AutocompleteMatch::SEARCH_SUGGEST:
     // A match that uses a non-default search engine (e.g. for tab-to-search).
     case AutocompleteMatch::SEARCH_OTHER_ENGINE:
       return true;
 
     default:
       return false;
   }
 }
 
-}
+}  // namespace
 
-const int NetworkActionPredictor::kMaximumDaysToKeepEntry = 14;
+namespace predictors {
 
-double NetworkActionPredictor::hit_weight_ = 1.0;
+const int AutocompleteActionPredictor::kMaximumDaysToKeepEntry = 14;
 
-NetworkActionPredictor::NetworkActionPredictor(Profile* profile)
+double AutocompleteActionPredictor::hit_weight_ = 1.0;
+
+AutocompleteActionPredictor::AutocompleteActionPredictor(Profile* profile)
     : profile_(profile),
-      db_(new NetworkActionPredictorDatabase(profile)),
+      db_(PredictorDatabaseFactory::GetForProfile(
+          profile)->autocomplete_table()),
       initialized_(false) {
-  content::BrowserThread::PostTask(content::BrowserThread::DB, FROM_HERE,
-      base::Bind(&NetworkActionPredictorDatabase::Initialize, db_));
-
   // Request the in-memory database from the history to force it to load so it's
   // available as soon as possible.
   HistoryService* history_service =
       profile_->GetHistoryService(Profile::EXPLICIT_ACCESS);
   if (history_service)
     history_service->InMemoryDatabase();
 
   // Create local caches using the database as loaded. We will garbage collect
   // rows from the caches and the database once the history service is
   // available.
-  std::vector<NetworkActionPredictorDatabase::Row>* rows =
-      new std::vector<NetworkActionPredictorDatabase::Row>();
+  std::vector<AutocompleteActionPredictorTable::Row>* rows =
+      new std::vector<AutocompleteActionPredictorTable::Row>();
   content::BrowserThread::PostTaskAndReply(
       content::BrowserThread::DB, FROM_HERE,
-      base::Bind(&NetworkActionPredictorDatabase::GetAllRows, db_, rows),
-      base::Bind(&NetworkActionPredictor::CreateCaches, AsWeakPtr(),
+      base::Bind(&AutocompleteActionPredictorTable::GetAllRows,
+                 db_,
+                 rows),
+      base::Bind(&AutocompleteActionPredictor::CreateCaches, AsWeakPtr(),
                  base::Owned(rows)));
-
 }
 
-NetworkActionPredictor::~NetworkActionPredictor() {
+AutocompleteActionPredictor::~AutocompleteActionPredictor() {
 }
 
-void NetworkActionPredictor::RegisterTransitionalMatches(
+void AutocompleteActionPredictor::RegisterTransitionalMatches(
     const string16& user_text,
     const AutocompleteResult& result) {
   if (user_text.length() < kMinimumUserTextLength)
     return;
   const string16 lower_user_text(base::i18n::ToLower(user_text));
 
   // Merge this in to an existing match if we already saw |user_text|
   std::vector<TransitionalMatch>::iterator match_it =
       std::find(transitional_matches_.begin(), transitional_matches_.end(),
                 lower_user_text);
 
   if (match_it == transitional_matches_.end()) {
     TransitionalMatch transitional_match;
     transitional_match.user_text = lower_user_text;
     match_it = transitional_matches_.insert(transitional_matches_.end(),
                                             transitional_match);
   }
 
   for (AutocompleteResult::const_iterator it = result.begin();
        it != result.end(); ++it) {
     if (std::find(match_it->urls.begin(), match_it->urls.end(),
                   it->destination_url) == match_it->urls.end()) {
       match_it->urls.push_back(it->destination_url);
     }
   }
 }
 
-void NetworkActionPredictor::ClearTransitionalMatches() {
+void AutocompleteActionPredictor::ClearTransitionalMatches() {
   transitional_matches_.clear();
 }
 
 // Given a match, return a recommended action.
-NetworkActionPredictor::Action NetworkActionPredictor::RecommendAction(
-    const string16& user_text,
-    const AutocompleteMatch& match) const {
+AutocompleteActionPredictor::Action
+    AutocompleteActionPredictor::RecommendAction(
+        const string16& user_text,
+        const AutocompleteMatch& match) const {
   bool is_in_db = false;
   const double confidence = CalculateConfidence(user_text, match, &is_in_db);
   DCHECK(confidence >= 0.0 && confidence <= 1.0);
 
-  UMA_HISTOGRAM_BOOLEAN("NetworkActionPredictor.MatchIsInDb", is_in_db);
+  UMA_HISTOGRAM_BOOLEAN("AutocompleteActionPredictor.MatchIsInDb", is_in_db);
 
   if (is_in_db) {
     // Multiple enties with the same URL are fine as the confidence may be
     // different.
     tracked_urls_.push_back(std::make_pair(match.destination_url, confidence));
-    UMA_HISTOGRAM_COUNTS_100("NetworkActionPredictor.Confidence",
+    UMA_HISTOGRAM_COUNTS_100("AutocompleteActionPredictor.Confidence",
                              confidence * 100);
   }
 
   // Map the confidence to an action.
   Action action = ACTION_NONE;
   for (int i = 0; i < LAST_PREDICT_ACTION; ++i) {
     if (confidence >= kConfidenceCutoff[i]) {
       action = static_cast<Action>(i);
       break;
     }
@@ skipping 10 matching lines @@
        !prerender::IsOmniboxEnabled(profile_))) {
     action = ACTION_PRECONNECT;
   }
 
   return action;
 }
 
 // Return true if the suggestion type warrants a TCP/IP preconnection.
 // i.e., it is now quite likely that the user will select the related domain.
 // static
-bool NetworkActionPredictor::IsPreconnectable(const AutocompleteMatch& match) {
+bool AutocompleteActionPredictor::IsPreconnectable(
+    const AutocompleteMatch& match) {
   return IsAutocompleteMatchSearchType(match);
 }
 
-void NetworkActionPredictor::Shutdown() {
-  db_->OnPredictorDestroyed();
+void AutocompleteActionPredictor::Shutdown() {
 }
 
-void NetworkActionPredictor::Observe(
+void AutocompleteActionPredictor::Observe(
     int type,
     const content::NotificationSource& source,
     const content::NotificationDetails& details) {
   switch (type) {
     case chrome::NOTIFICATION_HISTORY_URLS_DELETED: {
       DCHECK(initialized_);
       const content::Details<const history::URLsDeletedDetails>
           urls_deleted_details =
               content::Details<const history::URLsDeletedDetails>(details);
       if (urls_deleted_details->all_history)
@@ skipping 24 matching lines @@
                                      content::Source<Profile>(profile_));
       break;
     }
 
     default:
       NOTREACHED() << "Unexpected notification observed.";
       break;
   }
 }
 
-void NetworkActionPredictor::OnOmniboxOpenedUrl(const AutocompleteLog& log) {
+void AutocompleteActionPredictor::OnOmniboxOpenedUrl(
+    const AutocompleteLog& log) {
   if (log.text.length() < kMinimumUserTextLength)
     return;
 
   const AutocompleteMatch& match = log.result.match_at(log.selected_index);
 
   UMA_HISTOGRAM_BOOLEAN(
       StringPrintf("Prerender.OmniboxNavigationsCouldPrerender_%.1f%s",
                    get_hit_weight(),
                    prerender::PrerenderManager::GetModeString()).c_str(),
       prerender::IsOmniboxEnabled(profile_));
 
   const GURL& opened_url = match.destination_url;
 
   // If the Omnibox triggered a prerender but the URL doesn't match the one the
   // user is navigating to, cancel the prerender.
   prerender::PrerenderManager* prerender_manager =
       prerender::PrerenderManagerFactory::GetForProfile(profile_);
   // |prerender_manager| can be NULL in incognito mode or if prerendering is
   // otherwise disabled.
   if (prerender_manager && !prerender_manager->IsPrerendering(opened_url))
     prerender_manager->CancelOmniboxPrerenders();
 
   const string16 lower_user_text(base::i18n::ToLower(log.text));
 
-  BeginTransaction();
   // Traverse transitional matches for those that have a user_text that is a
   // prefix of |lower_user_text|.
+  std::vector<AutocompleteActionPredictorTable::Row> rows_to_add;
+  std::vector<AutocompleteActionPredictorTable::Row> rows_to_update;
+
   for (std::vector<TransitionalMatch>::const_iterator it =
        transitional_matches_.begin(); it != transitional_matches_.end();
        ++it) {
     if (!StartsWith(lower_user_text, it->user_text, true))
       continue;
 
     // Add entries to the database for those matches.
     for (std::vector<GURL>::const_iterator url_it = it->urls.begin();
          url_it != it->urls.end(); ++url_it) {
       DCHECK(it->user_text.length() >= kMinimumUserTextLength);
       const DBCacheKey key = { it->user_text, *url_it };
       const bool is_hit = (*url_it == opened_url);
 
-      NetworkActionPredictorDatabase::Row row;
+      AutocompleteActionPredictorTable::Row row;
       row.user_text = key.user_text;
       row.url = key.url;
 
       DBCacheMap::iterator it = db_cache_.find(key);
       if (it == db_cache_.end()) {
         row.id = guid::GenerateGUID();
         row.number_of_hits = is_hit ? 1 : 0;
         row.number_of_misses = is_hit ? 0 : 1;
 
-        AddRow(key, row);
+        rows_to_add.push_back(row);
       } else {
         DCHECK(db_id_cache_.find(key) != db_id_cache_.end());
         row.id = db_id_cache_.find(key)->second;
         row.number_of_hits = it->second.number_of_hits + (is_hit ? 1 : 0);
         row.number_of_misses = it->second.number_of_misses + (is_hit ? 0 : 1);
 
-        UpdateRow(it, row);
+        rows_to_update.push_back(row);
       }
     }
   }
-  CommitTransaction();
+  if (rows_to_add.size() > 0 || rows_to_update.size() > 0)
+    AddAndUpdateRows(rows_to_add, rows_to_update);
 
   ClearTransitionalMatches();
 
   // Check against tracked urls and log accuracy for the confidence we
   // predicted.
   for (std::vector<std::pair<GURL, double> >::const_iterator it =
        tracked_urls_.begin(); it != tracked_urls_.end();
        ++it) {
     if (opened_url == it->first) {
-      UMA_HISTOGRAM_COUNTS_100("NetworkActionPredictor.AccurateCount",
+      UMA_HISTOGRAM_COUNTS_100("AutocompleteActionPredictor.AccurateCount",
                                it->second * 100);
     }
   }
   tracked_urls_.clear();
 }
 
-void NetworkActionPredictor::DeleteOldIdsFromCaches(
+void AutocompleteActionPredictor::DeleteOldIdsFromCaches(
     history::URLDatabase* url_db,
-    std::vector<NetworkActionPredictorDatabase::Row::Id>* id_list) {
+    std::vector<AutocompleteActionPredictorTable::Row::Id>* id_list) {
   CHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
   DCHECK(url_db);
   DCHECK(id_list);
   id_list->clear();
   for (DBCacheMap::iterator it = db_cache_.begin(); it != db_cache_.end();) {
     history::URLRow url_row;
 
     if ((url_db->GetRowForURL(it->first.url, &url_row) == 0) ||
         ((base::Time::Now() - url_row.last_visit()).InDays() >
          kMaximumDaysToKeepEntry)) {
       const DBIdCacheMap::iterator id_it = db_id_cache_.find(it->first);
       DCHECK(id_it != db_id_cache_.end());
       id_list->push_back(id_it->second);
       db_id_cache_.erase(id_it);
       db_cache_.erase(it++);
     } else {
       ++it;
     }
   }
 }
 
-void NetworkActionPredictor::DeleteOldEntries(history::URLDatabase* url_db) {
+void AutocompleteActionPredictor::DeleteOldEntries(
+    history::URLDatabase* url_db) {
   CHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
   DCHECK(!initialized_);
 
-  std::vector<NetworkActionPredictorDatabase::Row::Id> ids_to_delete;
+  std::vector<AutocompleteActionPredictorTable::Row::Id> ids_to_delete;
   DeleteOldIdsFromCaches(url_db, &ids_to_delete);
 
   content::BrowserThread::PostTask(content::BrowserThread::DB, FROM_HERE,
-      base::Bind(&NetworkActionPredictorDatabase::DeleteRows, db_,
+      base::Bind(&AutocompleteActionPredictorTable::DeleteRows,
+                 db_,
                  ids_to_delete));
 
   // Register for notifications and set the |initialized_| flag.
   notification_registrar_.Add(this, chrome::NOTIFICATION_OMNIBOX_OPENED_URL,
                               content::Source<Profile>(profile_));
   notification_registrar_.Add(this, chrome::NOTIFICATION_HISTORY_URLS_DELETED,
                               content::Source<Profile>(profile_));
   initialized_ = true;
 }
 
-void NetworkActionPredictor::CreateCaches(
-    std::vector<NetworkActionPredictorDatabase::Row>* rows) {
+void AutocompleteActionPredictor::CreateCaches(
+    std::vector<AutocompleteActionPredictorTable::Row>* rows) {
   CHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
   DCHECK(!initialized_);
   DCHECK(db_cache_.empty());
   DCHECK(db_id_cache_.empty());
 
-  for (std::vector<NetworkActionPredictorDatabase::Row>::const_iterator it =
+  for (std::vector<AutocompleteActionPredictorTable::Row>::const_iterator it =
        rows->begin(); it != rows->end(); ++it) {
     const DBCacheKey key = { it->user_text, it->url };
     const DBCacheValue value = { it->number_of_hits, it->number_of_misses };
     db_cache_[key] = value;
     db_id_cache_[key] = it->id;
   }
 
   // If the history service is ready, delete any old or invalid entries.
   HistoryService* history_service =
       profile_->GetHistoryService(Profile::EXPLICIT_ACCESS);
   if (!TryDeleteOldEntries(history_service)) {
     // Wait for the notification that the history service is ready and the URL
     // DB is loaded.
     notification_registrar_.Add(this, chrome::NOTIFICATION_HISTORY_LOADED,
                                 content::Source<Profile>(profile_));
   }
 }
 
-bool NetworkActionPredictor::TryDeleteOldEntries(HistoryService* service) {
+bool AutocompleteActionPredictor::TryDeleteOldEntries(HistoryService* service) {
   if (!service)
     return false;
 
   history::URLDatabase* url_db = service->InMemoryDatabase();
   if (!url_db)
     return false;
 
   DeleteOldEntries(url_db);
   return true;
 }
 
-double NetworkActionPredictor::CalculateConfidence(
+double AutocompleteActionPredictor::CalculateConfidence(
     const string16& user_text,
     const AutocompleteMatch& match,
     bool* is_in_db) const {
   const DBCacheKey key = { user_text, match.destination_url };
 
   *is_in_db = false;
   if (user_text.length() < kMinimumUserTextLength)
     return 0.0;
 
   const DBCacheMap::const_iterator iter = db_cache_.find(key);
   if (iter == db_cache_.end())
     return 0.0;
 
   *is_in_db = true;
   return CalculateConfidenceForDbEntry(iter);
 }
 
-double NetworkActionPredictor::CalculateConfidenceForDbEntry(
+double AutocompleteActionPredictor::CalculateConfidenceForDbEntry(
     DBCacheMap::const_iterator iter) const {
   const DBCacheValue& value = iter->second;
   if (value.number_of_hits < kMinimumNumberOfHits)
     return 0.0;
 
   const double number_of_hits = value.number_of_hits * hit_weight_;
   return number_of_hits / (number_of_hits + value.number_of_misses);
 }
 
-void NetworkActionPredictor::AddRow(
-    const DBCacheKey& key,
-    const NetworkActionPredictorDatabase::Row& row) {
+void AutocompleteActionPredictor::AddAndUpdateRows(
+    const AutocompleteActionPredictorTable::Rows& rows_to_add,
+    const AutocompleteActionPredictorTable::Rows& rows_to_update) {
   if (!initialized_)
     return;
 
-  DBCacheValue value = { row.number_of_hits, row.number_of_misses };
-  db_cache_[key] = value;
-  db_id_cache_[key] = row.id;
   content::BrowserThread::PostTask(content::BrowserThread::DB, FROM_HERE,
-      base::Bind(&NetworkActionPredictorDatabase::AddRow, db_, row));
+      base::Bind(&AutocompleteActionPredictorTable::AddAndUpdateRows,
+                 db_,
+                 rows_to_add,
+                 rows_to_update));
 
-  UMA_HISTOGRAM_ENUMERATION("NetworkActionPredictor.DatabaseAction",
-                            DATABASE_ACTION_ADD, DATABASE_ACTION_COUNT);
+  for (AutocompleteActionPredictorTable::Rows::const_iterator it =
+       rows_to_add.begin(); it != rows_to_add.end(); ++it) {
+    const DBCacheKey key = { it->user_text, it->url };
+    DBCacheValue value = { it->number_of_hits, it->number_of_misses };
+
+    DCHECK(db_cache_.find(key) == db_cache_.end());
+
+    db_cache_[key] = value;
+    db_id_cache_[key] = it->id;
+    UMA_HISTOGRAM_ENUMERATION("AutocompleteActionPredictor.DatabaseAction",
+                              DATABASE_ACTION_ADD, DATABASE_ACTION_COUNT);
+  }
+  for (AutocompleteActionPredictorTable::Rows::const_iterator it =
+       rows_to_update.begin(); it != rows_to_update.end(); ++it) {
+    const DBCacheKey key = { it->user_text, it->url };
+
+    DBCacheMap::iterator db_it = db_cache_.find(key);
+    DCHECK(db_it != db_cache_.end());
+    DCHECK(db_id_cache_.find(key) != db_id_cache_.end());
+
+    db_it->second.number_of_hits = it->number_of_hits;
+    db_it->second.number_of_misses = it->number_of_misses;
+    UMA_HISTOGRAM_ENUMERATION("AutocompleteActionPredictor.DatabaseAction",
+                              DATABASE_ACTION_UPDATE, DATABASE_ACTION_COUNT);
+  }
 }
 
-void NetworkActionPredictor::UpdateRow(
-    DBCacheMap::iterator it,
-    const NetworkActionPredictorDatabase::Row& row) {
-  if (!initialized_)
-    return;
-
-  DCHECK(it != db_cache_.end());
-  it->second.number_of_hits = row.number_of_hits;
-  it->second.number_of_misses = row.number_of_misses;
-  content::BrowserThread::PostTask(content::BrowserThread::DB, FROM_HERE,
-      base::Bind(&NetworkActionPredictorDatabase::UpdateRow, db_, row));
-  UMA_HISTOGRAM_ENUMERATION("NetworkActionPredictor.DatabaseAction",
-                            DATABASE_ACTION_UPDATE, DATABASE_ACTION_COUNT);
-}
-
-void NetworkActionPredictor::DeleteAllRows() {
+void AutocompleteActionPredictor::DeleteAllRows() {
   if (!initialized_)
     return;
 
   db_cache_.clear();
   db_id_cache_.clear();
   content::BrowserThread::PostTask(content::BrowserThread::DB, FROM_HERE,
-      base::Bind(&NetworkActionPredictorDatabase::DeleteAllRows, db_));
-  UMA_HISTOGRAM_ENUMERATION("NetworkActionPredictor.DatabaseAction",
+      base::Bind(&AutocompleteActionPredictorTable::DeleteAllRows,
+                 db_));
+  UMA_HISTOGRAM_ENUMERATION("AutocompleteActionPredictor.DatabaseAction",
                             DATABASE_ACTION_DELETE_ALL, DATABASE_ACTION_COUNT);
 }
 
-void NetworkActionPredictor::DeleteRowsWithURLs(const std::set<GURL>& urls) {
+void AutocompleteActionPredictor::DeleteRowsWithURLs(
+    const std::set<GURL>& urls) {
   if (!initialized_)
     return;
 
-  std::vector<NetworkActionPredictorDatabase::Row::Id> id_list;
+  std::vector<AutocompleteActionPredictorTable::Row::Id> id_list;
 
   for (DBCacheMap::iterator it = db_cache_.begin(); it != db_cache_.end();) {
     if (urls.find(it->first.url) != urls.end()) {
       const DBIdCacheMap::iterator id_it = db_id_cache_.find(it->first);
       DCHECK(id_it != db_id_cache_.end());
       id_list.push_back(id_it->second);
       db_id_cache_.erase(id_it);
       db_cache_.erase(it++);
     } else {
       ++it;
     }
   }
 
   content::BrowserThread::PostTask(content::BrowserThread::DB, FROM_HERE,
-      base::Bind(&NetworkActionPredictorDatabase::DeleteRows, db_, id_list));
-  UMA_HISTOGRAM_ENUMERATION("NetworkActionPredictor.DatabaseAction",
+      base::Bind(&AutocompleteActionPredictorTable::DeleteRows,
+                 db_,
+                 id_list));
+  UMA_HISTOGRAM_ENUMERATION("AutocompleteActionPredictor.DatabaseAction",
                             DATABASE_ACTION_DELETE_SOME, DATABASE_ACTION_COUNT);
 }
 
-void NetworkActionPredictor::BeginTransaction() {
-  if (!initialized_)
-    return;
-
-  content::BrowserThread::PostTask(content::BrowserThread::DB, FROM_HERE,
-      base::Bind(&NetworkActionPredictorDatabase::BeginTransaction, db_));
+AutocompleteActionPredictor::TransitionalMatch::TransitionalMatch() {
 }
 
-void NetworkActionPredictor::CommitTransaction() {
-  if (!initialized_)
-    return;
-
-  content::BrowserThread::PostTask(content::BrowserThread::DB, FROM_HERE,
-      base::Bind(&NetworkActionPredictorDatabase::CommitTransaction, db_));
+AutocompleteActionPredictor::TransitionalMatch::~TransitionalMatch() {
 }
 
-NetworkActionPredictor::TransitionalMatch::TransitionalMatch() {
-}
-
-NetworkActionPredictor::TransitionalMatch::~TransitionalMatch() {
-}
+}  // namespace predictors