Usage and Dynamic Variables

I would like add Groovy auto-completion to a JavaFX text editor.
Should I use similar code with the one from this project test cases? Please let me know if you have other examples to use.

The scripts are edited in an integrated environment and during execution they receive variables via a Groovy Binding. How can I let the language server know about this binding?
Here a sample on how the scripts are executed:

final Binding binding = new Binding();
        binding.setProperty( "project", form.layout.project );
        try {
            if ( connection != null ){
                binding.setProperty( "sql", connection );
            }
            final GroovyShell shell = new GroovyShell( binding, GroovyConfiguration.CONFIG );
            final Script script = shell.parse( getText(), getId() );
            return script.run();
        } catch ( IllegalArgumentException ex ) {
            throw ex;
        } catch ( Throwable ex ){
            throwFormScriptExecutionException(dataRow, ex );
        } finally {
            binding.setProperty( "out", null );
            binding.setProperty( "sql", null );
        }
        return null;