DaggerStep2_GetFeedHandler.java

public class GetFeedHandler implements RequestHandler<GetFeedRequest, GetFeedResponse> {
    @Inject LambdaLogger mLambdaLogger;
    @Inject @Named(TableConstants.FEED_USERID_CREATED_AT_INDEX) Index mSortedFeedIndex;
    @Inject @Named(QueryConstants.FEED_SORTED_QUERY) QuerySpec mSortedFeedQuery;

    public GetFeedResponse handleRequest(final GetFeedRequest input, final Context context) {
        Injector.getInjector(context).inject(this);
        
        final List<String> activityIds = getActivitiesForUser(input.getUserId());
        return new GetFeedResponse(activityIds);
    }

    private List<String> getActivitiesForUser(final String userId) {
        mLambdaLogger.log(String.format("Querying activities for user %s", userId));

        final ItemCollection<QueryOutcome> items = mSortedFeedIndex.query(buildQueryForUserId(userId));

        return extractUserIds(items);
    }
    
    private QuerySpec buildQueryForUserId(final String userId) {
        return mSortedFeedQuery
                .withValueMap(new ValueMap().withString(":userId", userId));
    }
    
    private List<String> extractUserIds(final ItemCollection<QueryOutcome> items) {
        final List<String> activityIds = new ArrayList<>();

        for (final Item activity : items) {
            final String activityId = (String) activity.get(TableConstants.FEED_ID_COLUMN);

            mLambdaLogger.log(String.format("Found activity %s", activityId));
            activityIds.add(activityId);
        }
        
        return activityIds;
    }
}