everit-restclient

Helper classes to make HTTP+JSON based REST calls. The library uses Jackson for JSON serialization/deserialization.

The original goal of this library to add some functions that help generating code from OpenAPI specification, so the code inside the generated classes are much less simple.

Create a RestClient instance

// Create a HttpClient instance.
HttpClient httpClient = ...

// Create a JSONObjectMapper instance. E.g.: based on Jackson or GSON
JSONObjectMapper objectMapper = ...

// Instantiate the rest client. You must close the instance after it
// is not necessary anymore. Closing the restClient instance will also
// close the httpClient instance.
RestClient restClient = new RestClient(httpClient, objectMapper);

Sample Rest function

/**
 * This is a sample rest function
 *
 * @param requestBody
 *     The user to add to the group. (required)
 *
 * @param pathParams
 *     A sample required path parameter. (required)
 *
 * @param queryParam1
 *      A sample optional query parameter. (optional)
 * 
 * @param restRequestEnhancer
 *     Adds the possibility to modify the rest request before sending
 *     out. This can be useful to change the basePath or add
 *     authorizations tokens for example.
 *
 * @return
 *     Some object that will be converted from JSON.
 */
public Single<MyReturnType> doSomeCall(MyBodyType requestBody,
    Long pathParam1, Optional<String> queryParam1,
    Optional<RestRequestEnhancer> restRequestEnhancer) {
  
  RestRequest.Builder requestBuilder = RestRequest.builder()
      .method(HttpMethod.POST)
      .basePath(DEFAULT_BASE_PATH)
      .path("/rest/api/{pathParam1}");
  
  Map<String, String> pathParams = new HashMap<>();
  pathParams.put("pathParam1", Objects.requireNonNull(pathParam1).toString());
  requestBuilder.pathParams(pathParams);
  
  Map<String, Collection<String>> queryParams = new HashMap<>();
  if (queryParam1.isPresent()) {
    queryParams.put("queryParam1", Collections.singleton(queryParam1));
  }
  requestBuilder.queryParams(queryParams);
  
  Map<String, String> headers = new HashMap<>();
  requestBuilder.headers(headers);
  
  requestBuilder.requestBody(Optional.of(requestBody));
  
  return RestCallUtil.callEndpoint(requestBuilder.build(),
      restRequestEnhancer, new TypeReference<MyReturnType>() {});
}

For more information, please see the Javadoc of the classes.

Handling errors

All responses that have status code >= 400 are propagated to the return type as RestException.