You can change interface method signatures at any time. If the interface is currently implemented, the mapping method for the implementing class is not compatible and therefore has a compilation error. See also "Using the Method Status List Browser", in Chapter 4.
When you change the signature of an interface method that has one or more mappings, the Compile Method message box is then displayed, stating that the method signature has changed, one or more references must be compiled, and prompting you to confirm that you want to compile now.
Click the Yes button to recompile the mapped method or methods immediately. Click the No button if you do not want the implementing method or methods recompiled immediately.
You must then change the signature of affected methods and then recompile them (by pressing F8 in the editor pane of each method implementor in the Class Browser or Status List Browser or by selecting the Compile command from the Methods menu).
If the interface method signature change results in a compile error in the implementing class, a message box is then displayed, advising you that the compile process has one or more errors, and prompting you to specify that you want to view the error list.
Click the Yes button to display the methods in implementing classes whose signatures need updating before recompilation. Click the No button if you do not want to view and update the methods in error now.
To automatically update the class method signature in the method in error (from the Class Browser) so that it matches that of its interface method, position the caret after the ( opening parenthesis symbol and then press Ctrl+1, Ctrl+2, or Ctrl+3.
The correct signature for the mapped method is then inserted.
For more details about compiling methods, see "Compiling All Methods Defined in a Class, Primitive Type, or Interface", in Chapter 3, and "Compiling Methods", in Chapter 4.