You can use the Value Expressions pane in the Logic tab to add value expressions to GEL actions with data operations (as discussed in Adding data operations) and expression constructs with conditions (as discussed in Adding Conditions).
You can remove the default options of data operations and conditions and replace it with any of the value expressions. To perform this, you must first close the default option (for example, the "(constant) <value_box>" for the Set Dataslot action) and then drag the value expression to the placeholder labeled, "Drop value expression here."
You can drag and configure the following GEL actions.
User Dataslot: To use a user-defined dataslot. For instance, you can set the value of another user-defined dataslot (or variable) to a user dataslot.
System Dataslot: To use a system (or predefined) dataslot. For instance, you can set the value of a user-defined dataslot (or variable) to a system dataslot. This option is not available for Web applications.
Constant Expression: To use a constant expression (or constant value). For instance, you can use this to revert the Set Dataslot and Set Context Variable actions (if you have changed the default options) to its default target constant value.
Custom Expressions: To use customized Java (or JavaScript). For instance, you can specify a Java (or JavaScript) function that returns a particular value, which can be assigned to a variable (or dataslot).
Note: You can also use the AutoComplete functionality to automatically add script functions. To activate AutoComplete, type jst. (for a Business Process) or bean. (for a Web application) in the respective box.
Context Variable: To use a context variable. For instance, you can copy the value of a context variable to another context variable.