In some cases, certain functionality (functions, commands, etc..) requires certain licensing before submitting the query.
Currently this is implemented through Function#checkLicense which unfortunately restricts this checks to functions only.
This can be improved by adding a specialized interface that relevant Functions, command, etc.. can implement when needed:

public interface LicenseAware {
     boolean licenseCheck(XPackLicenseState state) {}
}

Furthermore the relevant check can be early, right after parsing to avoid unnecessary index calls.