XFA Specification
Chapter 1, Introduction to XML Forms Architecture (XFA)
Lifecycle of an XFA Form
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In a template designing application with a graphic interface, a template designer can start with a blank
canvas and place objects, or the author can start with a schema, for example, XML-Schema [XML-Schema],
data source or data file. When starting with a schema, the designer can select portions or all of the schema
tree and place them on the template canvas, and the design tool will create subform/field structure, with
properly-typed fields, template-defined bindings. layout constraints, and processing rules.
Filling Out an XFA Form
Opening a Form
When a user directs an XFA processing application to open an XFA form, the application goes through the
following general steps:
1. Draw the initial form. The XFA processing application uses the XFA template to determine the initial
form appearance and to obtain default data. If the application supports only form printing or
machine-provided data, this task is omitted.
2. Associate data with specific fields. If data is included in the XFA form, the application creates logical
connections between the data and the fields.
3. Display data in fields. The application displays the data associated with each field. Time, date, or
number data may be formatted. The data may result in the form appearance changing, as fields grow
or subforms are added to accommodate the data.
4. Activate events. The application activates events associated with creation of the form. Such events can
include interacting with a server to obtain data used in the form.
5. Update form. The XFA processing application executes calculations and data validations for any fields
whose values have changed.
The above description is a simplification. Much more goes on behind the scenes, as will be described in
later chapters. In addition, the actions described above may take place in different sequences.
Providing Data to the Form
The user provides data by bringing a field into focus and then entering data. A field can be brought into
focus by using a mouse to select the field or by entering key(board) sequences. The data is processed as
described in Step
5.
on
page 23.
Saving an In-Progress Version of the Form
XFA processing applications will typically allow users to save an in-progress or committed version of a
form. (See
method for requesting the save is application-specific.
The format used for saving a form is typically to serialize the form data and optionally other parts of the
form not represented by the original form components. Serialization of the XFA form data and other
XML-based component would be structured according to the schema of the component being saved.
Committing a Form
After completing a form, the user is ready to submit the form. That is, the user has supplied all information
required by the form and repaired any errors reported by the form. Committed really means that it has
been released for further processing.