Could you provide some sample Java code for Cognito UserPool Authorizer client

[sysout]

This is from the generated java SDK

import com.amazonaws.ImmutableRequest;

import spacefinder.auth.SpacefinderUserPoolAuthorizer;

public class SpacefinderUserPoolAuthorizerImpl implements SpacefinderUserPoolAuthorizer {

	@Override
	public String generateToken(ImmutableRequest<?> request) {
		return "some-generated-auth-token";
	}
}

Obviously, there is a big gap between "some-generated-auth-token" and a working Authorizer client.
We want to use Cognito User Pools + Cognito Federated Identities + Amazon API Gateway to create an API for third party developers.
I really appreciate the help.