text: ////////////////////////////////////////////////////////////////////////////////
  /// DISCLAIMER
  ///
  /// Copyright 2014-2016 ArangoDB GmbH, Cologne, Germany
  /// Copyright 2004-2014 triAGENS GmbH, Cologne, Germany
  ///
  /// 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.
  ///
  /// Copyright holder is ArangoDB GmbH, Cologne, Germany
  ///
  /// @author Jan Steemann
  ////////////////////////////////////////////////////////////////////////////////
  
  #include "RestQueryCacheHandler.h"
  #include "Aql/QueryCache.h"
  #include "Rest/HttpRequest.h"
  
  using namespace arangodb;
  using namespace arangodb::aql;
  using namespace arangodb::basics;
  using namespace arangodb::rest;
  
  RestQueryCacheHandler::RestQueryCacheHandler(GeneralRequest* request,
                                               GeneralResponse* response)
      : RestVocbaseBaseHandler(request, response) {}
  
  RestStatus RestQueryCacheHandler::execute() {
    // extract the sub-request type
    auto const type = _request->requestType();
  
    switch (type) {
      case rest::RequestType::DELETE_REQ:
        clearCache();
        break;
      case rest::RequestType::GET:
        readProperties();
        break;
      case rest::RequestType::PUT:
        replaceProperties();
        break;
      default:
        generateNotImplemented("ILLEGAL " + DOCUMENT_PATH);
        break;
    }
  
    // this handler is done
    return RestStatus::DONE;
  }
  
  ////////////////////////////////////////////////////////////////////////////////
  /// @brief was docuBlock DeleteApiQueryCache
  ////////////////////////////////////////////////////////////////////////////////
  
  bool RestQueryCacheHandler::clearCache() {
    auto queryCache = arangodb::aql::QueryCache::instance();
    queryCache->invalidate();
      
    VPackBuilder result;
    result.add(VPackValue(VPackValueType::Object));
    result.add(StaticStrings::Error, VPackValue(false));
    result.add(StaticStrings::Code, VPackValue((int)rest::ResponseCode::OK));
    result.close();
    generateResult(rest::ResponseCode::OK, result.slice());
    return true;
  }
  
  ////////////////////////////////////////////////////////////////////////////////
  /// @brief was docuBlock GetApiQueryCacheProperties
  ////////////////////////////////////////////////////////////////////////////////
  
  bool RestQueryCacheHandler::readProperties() {
    auto queryCache = arangodb::aql::QueryCache::instance();
  
    VPackBuilder result = queryCache->properties();
    generateResult(rest::ResponseCode::OK, result.slice());
    return true;
  }
  
  ////////////////////////////////////////////////////////////////////////////////
  /// @brief was docuBlock PutApiQueryCacheProperties
  ////////////////////////////////////////////////////////////////////////////////
  
  bool RestQueryCacheHandler::replaceProperties() {
    auto const& suffixes = _request->suffixes();
  
    if (suffixes.size() != 1 || suffixes[0] != "properties") {
      generateError(rest::ResponseCode::BAD,
                    TRI_ERROR_HTTP_BAD_PARAMETER,
                    "expecting PUT /_api/query-cache/properties");
      return true;
    }
  
    bool validBody = false;
    VPackSlice body = this->parseVPackBody(validBody);
    if (!validBody) {
      // error message generated in parseJsonBody
      return true;
    }
  
    if (!body.isObject()) {
      generateError(rest::ResponseCode::BAD,
                    TRI_ERROR_HTTP_BAD_PARAMETER, "expecting a JSON-Object body");
      return true;
    }
  
    auto queryCache = arangodb::aql::QueryCache::instance();
  
    std::pair<std::string, size_t> cacheProperties;
    queryCache->properties(cacheProperties);
  
    VPackSlice attribute = body.get("mode");
    if (attribute.isString()) {
      cacheProperties.first = attribute.copyString();
    }
  
    attribute = body.get("maxResults");
  
    if (attribute.isNumber()) {
      cacheProperties.second = static_cast<size_t>(attribute.getUInt());
    }
  
    queryCache->setProperties(cacheProperties);
  
    return readProperties();
  }
  