Developer Guide

Recording Annotations, Metadata, and User IDs

In the game model class, the application records Game objects in a metadata block each time it saves a game in DynamoDB. Separately, the application records game IDs in annotations for use with filter expressions.

Example src/main/java/scorekeep/ – Annotations and Metadata

import com.amazonaws.xray.AWSXRay;
import com.amazonaws.xray.entities.Segment;
import com.amazonaws.xray.entities.Subsegment;
  public void saveGame(Game game) throws SessionNotFoundException {
    // wrap in subsegment
    Subsegment subsegment = AWSXRay.beginSubsegment("## GameModel.saveGame");
    try {
      // check session
      String sessionId = game.getSession();
      if (sessionModel.loadSession(sessionId) == null ) {
        throw new SessionNotFoundException(sessionId);
      Segment segment = AWSXRay.getCurrentSegment();
      subsegment.putMetadata("resources", "game", game);
      segment.putAnnotation("gameid", game.getId());;
    } catch (Exception e) {
      throw e;
    } finally {

In the move controller, the application records user IDs with setUser. User IDs are recorded in a separate field on segments and are indexed for use with search.

Example src/main/java/scorekeep/ – User ID

import com.amazonaws.xray.AWSXRay;
  @RequestMapping(value="/{userId}", method=RequestMethod.POST)
  public Move newMove(@PathVariable String sessionId, @PathVariable String gameId, @PathVariable String userId, @RequestBody String move) throws SessionNotFoundException, GameNotFoundException, StateNotFoundException, RulesException {
    return moveFactory.newMove(sessionId, gameId, userId, move);