The TokenValidatorParameters class is a collection of configuration properties to use in validating the token, which are populated by the STS operations using information collated from the request, or static configuration, etc. The properties of the TokenValidatorParameters are:
STSPropertiesMBean stsProperties - A configuration MBean that holds the configuration for the STS as a whole.
Principal principal - The current client Principal object
WebServiceContext webServiceContext - The current web service context object. This allows access to the client request.
KeyRequirements keyRequirements - A set of configuration properties relating to keys.
TokenRequirements tokenRequirements - A set of configuration properties relating to the token.
TokenStore tokenStore - A cache used to retrieve tokens.
String realm - The realm to validate the token in (this should be the same as the realm passed to "canHandleToken").
ReceivedToken token - Represents the token that was received for validation.
If this looks complicated then remember that the STS will take care of populating all of these properties from the request and some additional configuration. You only need to worry about the TokenValidatorParameters object if you are creating your own TokenValidator implementation.