private String getServiceId(final Service service) {
        val serviceId = FunctionUtils.doUnchecked(() -> serviceSelectionStrategy.resolveService(service).getId());
        return DigestUtils.abbreviate(serviceId, properties.getAbbreviationLength());
    }
Converts the Credential object into a String resource identifier.

@author Scott Battaglia
@since 3.1.2
core/cas-server-core-audit-api/src/main/java/org/apereo/cas/audit/spi/resource/CredentialsAsFirstParameterResourceResolver.java