The previous chapter showed you how to define who carries out tasks in a process. This chapter shows you how to define the data that is required for the Tahiti application. The BPMN standard does not specifically deal with data, but it is not surprising that you need data to make a process work. Data is the reason that applications and processes exist. Most processes require data as input and produce data as output. You need to define a data model that applies to all the components of the Tahiti application, not just to the processes.
The data model is defined as a set of Java objects. If you are not familiar with the concept of objects, do not worry about this. Just think of an object as a template, like a template for a document. From the template, you can create any number of documents, each one different but all following the same pattern.
When defining the data model for a process or an application, you need to think about the lifetime of the data and where it is used. The answer to these questions determines where it needs to be stored.