@Override
    public AuthenticationHandlerExecutionResult authenticate(final Credential credential, final Service service) {
        LOGGER.debug("Trusting credential for: [{}]", credential);
        val bearingCredential = (PrincipalBearingCredential) credential;
        return new DefaultAuthenticationHandlerExecutionResult(this, bearingCredential, bearingCredential.getPrincipal());
    }
AuthenticationHandler which authenticates Principal-bearing credentials.
Authentication must have occurred at the time the Principal-bearing
credentials were created, so we perform no further authentication. Thus
merely by being presented a PrincipalBearingCredential, this handler returns
true.

@author Andrew Petro
@since 3.0.0
support/cas-server-support-trusted/src/main/java/org/apereo/cas/adaptors/trusted/authentication/handler/support/PrincipalBearingCredentialsAuthenticationHandler.java