CF Service Facade with XsuaaTokenFlow

CFServiceFacade.java

package my.util;

import java.net.URI;
import java.time.Instant;
import java.util.Map;

import com.sap.cloud.security.xsuaa.client.ClientCredentials;
import com.sap.cloud.security.xsuaa.client.DefaultOAuth2TokenService;
import com.sap.cloud.security.xsuaa.client.OAuth2TokenResponse;
import com.sap.cloud.security.xsuaa.client.XsuaaDefaultEndpoints;
import com.sap.cloud.security.xsuaa.tokenflows.XsuaaTokenFlows;

import lombok.Getter;

import io.pivotal.cfenv.core.CfCredentials;
import io.pivotal.cfenv.core.CfEnv;

public class CFServiceFacade {
    private static CfEnv cfEnv = new CfEnv();

    @Getter
    private final Map<String, Object> serviceCredentials;

    private OAuth2TokenResponse serviceTokenResponse;

    public CFServiceFacade(String serviceInstanceName) {
        CfCredentials cfCredentials = cfEnv.findCredentialsByName(serviceInstanceName);
        serviceCredentials = cfCredentials.getMap();
    }

    public String getServiceJWT(String tokenServiceUrlProperty) {
        if (serviceTokenResponse != null) {
            if (Instant.now().compareTo(serviceTokenResponse.getExpiredAt()) > 0) {
                // token is expired --> refresh
                serviceTokenResponse = null;
                return getServiceJWT(tokenServiceUrlProperty);
            }

            return serviceTokenResponse.getAccessToken();
        }
        try {
            URI xsuaaUri = new URI((String) serviceCredentials.get(tokenServiceUrlProperty));
            String clientid = (String) serviceCredentials.get("clientid");
            String clientsecret = (String) serviceCredentials.get("clientsecret");

            // use the XSUAA client library to ease the implementation of the user token
            // exchange flow
            XsuaaTokenFlows tokenFlows = new XsuaaTokenFlows(
                    new DefaultOAuth2TokenService(),
                    new XsuaaDefaultEndpoints(xsuaaUri.toString()),
                    new ClientCredentials(clientid, clientsecret));

            serviceTokenResponse = tokenFlows.clientCredentialsTokenFlow().execute();
            return serviceTokenResponse.getAccessToken();
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }

    public String getServiceProperty(String propertyName) {
        return (String) serviceCredentials.get(propertyName);
    }

}