@Override
    public boolean supports(final Credential credential) {
        return credential != null && credential.getId() != null;
    }
Resolves principals by querying a data source using the Person Directory API.
The {@link Principal#getAttributes()} are populated by the results of the
query and the principal ID may optionally be set by proving an attribute whose first non-null value is used;
otherwise the credential ID is used for the principal ID.

@author Marvin S. Addison
@since 4.0.0
support/cas-server-support-person-directory-core/src/main/java/org/apereo/cas/authentication/principal/resolvers/PersonDirectoryPrincipalResolver.java