Adding a discriminator to a schema object

You can add a discriminator to a DFDL schema object to enable the DFDL parser to resolve a point of uncertainty.

Before you begin

Create or open a DFDL schema file. See DFDL schema editor for a description of the DFDL schema editor.

Procedure

  1. In the Editor view, select the DFDL schema object on which you want to add a discriminator.
  2. On the Asserts and Discriminators tab of the DFDL Properties area, select Discriminators, then click Add discriminator. If an assert is already applied to the object, the Discriminators option is disabled, as an object cannot have both an assert and a discriminator applied to it.
    A new entry in the table is created.
  3. Enter your test expression in the Test Condition field, and a human-readable failure message in the Message field.
    Content assistance is available for the Test Condition field; press Ctrl+Space to open the XPath Expression Builder.
  4. Save your message model.

Results

Your discriminator is used when the message model is run.