By Arda Eralp on Mar 03, 2014
What Is Expression Language?
Expression Language is used for adding addition logic to the runtime customization of page components.
The examples provided in this document serve the following basic customization needs, and whilst more advanced logic is possible venturing into great complexity may take your customization beyond the scope that page composer is designed to support.
• Dynamically set a field to default a specific value
• Dynamically set the display properties of a specific field
• Conditionally hide or disable a field or region
Generally EL statements return either a value such as ‘Richard’, or a Boolean such as TRUE if the test is a success. These are then used in setting ADF page component properties, such as Value, Required, or Visible. The examples in this document include a mixture of return values used for setting various properties. In ADF a partial page refresh is used to fire the EL logic, and careful testing in a safe environment is needed to ensure your EL executes at the expected places. An example might be properly defaulting values for fields upon actions such as create, edit, and re-edit.
In addition, please be aware that not every page isintended to be fully customizable, and even those that are may not always expose the component properties against which you might wish to add custom expression logic. As such expectations of what is possible should be set based on careful testing of each case, and not on any broad assumptions.[Read More]