text: // Copyright (c) 2015 Uber Technologies, Inc.
  //
  // Permission is hereby granted, free of charge, to any person obtaining a copy
  // of this software and associated documentation files (the "Software"), to deal
  // in the Software without restriction, including without limitation the rights
  // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  // copies of the Software, and to permit persons to whom the Software is
  // furnished to do so, subject to the following conditions:
  //
  // The above copyright notice and this permission notice shall be included in
  // all copies or substantial portions of the Software.
  //
  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  // THE SOFTWARE.
  'use strict';
  
  function createChecksumComputedHandler(ringpop) {
      var ringLogger = ringpop.loggerFactory.getLogger('ring');
  
      return function onRingChecksumComputed(event) {
          ringpop.stat('increment', 'ring.checksum-computed');
          ringpop.stat('gauge', 'ring.checksum', event.checksum);
          ringpop.emit('ringChecksumComputed');
  
          if (event.oldChecksum !== event.checksum) {
              ringLogger.debug('ringpop ring computed new checksum', {
                  local: ringpop.whoami(),
                  checksum: event.checksum,
                  oldChecksum: event.oldChecksum,
                  timestamp: event.timestamp
              });
          }
      };
  }
  
  function createRingChangedHandler(ringpop) {
      return function onRingChanged(event) {
          ringpop.stat('increment', 'ring.changed');
          ringpop.emit('ringChanged', event);
      };
  }
  
  function createServerAddedHandler(ringpop) {
      return function onRingServerAdded() {
          ringpop.stat('increment', 'ring.server-added');
          ringpop.emit('ringServerAdded');
      };
  }
  
  function createServerRemovedHandler(ringpop) {
      return function onRingServerRemoved() {
          ringpop.stat('increment', 'ring.server-removed');
          ringpop.emit('ringServerRemoved');
      };
  }
  
  function register(ringpop) {
      var ring = ringpop.ring;
      ring.on('added', createServerAddedHandler(ringpop));
      ring.on('checksumComputed', createChecksumComputedHandler(ringpop));
      ring.on('ringChanged', createRingChangedHandler(ringpop));
      ring.on('removed', createServerRemovedHandler(ringpop));
  }
  
  module.exports = {
      createChecksumComputedHandler: createChecksumComputedHandler,
      createRingChangedHandler: createRingChangedHandler,
      createServerAddedHandler: createServerAddedHandler,
      createServerRemovedHandler: createServerRemovedHandler,
      register: register
  };
  