@Override
	public String[] profilesToActivate() {
		return getScript() == null ? new String[] { "use-expression" } : new String[] { "use-script" };
	}
User can't explicitly set both script and expression.
spring-xd-module-spi/src/main/java/org/springframework/xd/module/options/mixins/ExpressionOrScriptMixin.java