Inline query parameter and header processing in impls

Author: mgyucht

databricks-sdk-java/src/main/java/com/databricks/sdk/core/ApiClient.java

@@ -151,7 +151,7 @@ private ApiClient(Builder builder) {
     bodyLogger = new BodyLogger(mapper, 1024, debugTruncateBytes);
   }
 
-  private static <I> void setQuery(Request in, I entity) {
+  public static <I> void setQuery(Request in, I entity) {
     if (entity == null) {
       return;
     }
@@ -239,7 +239,7 @@ private <I> Request prepareRequest(String method, String path, I in, Map<String,
    * @param target Expected pojo type
    * @return POJO of requested type
    */
-  private <T> T execute(Request in, Class<T> target) throws IOException {
+  public <T> T execute(Request in, Class<T> target) throws IOException {
     Response out = getResponse(in);
     if (target == Void.class) {
       return null;
@@ -478,7 +478,7 @@ public <T> void deserialize(Response response, T object) throws IOException {
     }
   }
 
-  private String serialize(Object body) throws JsonProcessingException {
+  public String serialize(Object body) throws JsonProcessingException {
     if (body == null) {
       return null;
     }

databricks-sdk-java/src/main/java/com/databricks/sdk/core/DatabricksConfig.java

@@ -586,11 +586,13 @@ private OpenIDConnectEndpoints fetchDefaultOidcEndpoints() throws IOException {
             .withHttpClient(getHttpClient())
             .withGetHostFunc(v -> getHost())
             .build();
-    return apiClient.execute("GET",
-        "/oidc/.well-known/oauth-authorization-server",
-        null,
-        OpenIDConnectEndpoints.class,
-        new HashMap<>());
+    try {
+      return apiClient.execute(
+          new Request("GET", "/oidc/.well-known/oauth-authorization-server"),
+          OpenIDConnectEndpoints.class);
+    } catch (IOException e) {
+      throw new DatabricksException("IO error: " + e.getMessage(), e);
+    }
   }
 
   @Override

databricks-sdk-java/src/main/java/com/databricks/sdk/core/oauth/RefreshableTokenSource.java

@@ -4,6 +4,7 @@
 import com.databricks.sdk.core.DatabricksException;
 import com.databricks.sdk.core.http.FormRequest;
 import com.databricks.sdk.core.http.HttpClient;
+import com.databricks.sdk.core.http.Request;
 import java.time.LocalDateTime;
 import java.time.temporal.ChronoUnit;
 import java.util.Base64;
@@ -61,12 +62,11 @@ protected static Token retrieveToken(
         break;
     }
     headers.put("Content-Type", "application/x-www-form-urlencoded");
+    Request req = new Request("POST", tokenUrl, FormRequest.wrapValuesInList(params));
+    req.withHeaders(headers);
     try {
       ApiClient apiClient = new ApiClient.Builder().withHttpClient(hc).build();
-
-      OAuthResponse resp =
-          apiClient.execute("POST",
-              tokenUrl, FormRequest.wrapValuesInList(params), OAuthResponse.class, headers);
+      OAuthResponse resp = apiClient.execute(req, OAuthResponse.class);
       if (resp.getErrorCode() != null) {
         throw new IllegalArgumentException(resp.getErrorCode() + ": " + resp.getErrorSummary());
       }