Java Spring Decisionrules Example

Example call to decision rules api using spring rest template. This simple project shows how can you call decision rules api mainly

• init rest template
• add authorization headers
• execute sample rule on decisionrules

How to execute this example

1. Clone this repo to your computer

git clone https://github.com/decisionrules/java-spring-decisionrules.git

2. Add your sample rule id (every account on decision rules has this sample rule by default) and bearer token to Main class.

3. Execute main method in Main class and see the result

Decision rules call example

prepare header with token authorization

Every call to decision rules has to containg authorization header with bearer token.

HttpHeaders headers = new HttpHeaders();
headers.setContentType(MediaType.APPLICATION_JSON);
headers.set("Authorization", "Bearer " + bearerToken);

Call REST api with json in string

//prepare input object
String jsonInput = "{\"delivery\":{\"distance\":40,\"tariff\":\"basic\"},\"pack\":{\"weight\":4,\"longestSide\":50}}";
        

HttpEntity<String> entity = new HttpEntity<String>(jsonInput, headers);
ResponseEntity<String> response = restTemplate.exchange(formatUrl(connectionUrl, ruleId, version), HttpMethod.POST, entity, String.class);
        

Call REST api with java model

// register object mapper to rest template
final ObjectMapper objectMapper = new ObjectMapper();
MappingJackson2HttpMessageConverter converter = new MappingJackson2HttpMessageConverter(objectMapper);        
this.restTemplate.getMessageConverters().add(converter);

//prepare input object
ExampleRuleInput inputModel =

//call api
HttpEntity<ExampleRuleInput> entity = new HttpEntity<ExampleRuleInput>(inputModel, headers);
final List<ExampleRuleOutput> output = restTemplate.postForObject(formatUrl(connectionUrl, ruleId, version), entity, List.class);
        

Troubleshooting

Certificate problem

You can encounter certificate validation problem PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target javax.net.ssl.SSLHandshakeException: PKIX path building failed

Problem is caused by missing root Let's encrypt certificate in standard OpenJDK keystore. You need to download the root certificate from api.decisionrules.io web and install it into keystore with following command:

keytool -import -trustcacerts -file /path/to/cert.cer -alias somealiasforcert -keystore $JAVA_HOME/jre/lib/security/jssecacerts -storepass changeit

If for some reason you don't want to add root certificate, adding intermediate certificate should do the trick as well.