We need a scheduler to update the data for each trading day automatically. Spring Scheduler is an easy-to-use Spring component that we adopt in Scheduler.java. The user-defined cron schedule, scheduler.cron, is defined in application.yml. Once the task starts, it first calls getRegisterFunds() to get all the symbols. If the symbol has been performed by buildAnalyticsModel, then it is registered and it proceeds with the following workflow:

In the Python high-level Elasticsearch library section of Chapter 12, Elasticsearch from Python Programming, we implement the Bollinger Band. In the next section, we will use the Elasticsearch Java high-level REST client to implement it.