address review comments

fixes graylog-labs/graylog2-web-interface#1205

graylog2-rest-client/src/main/java/org/graylog2/restclient/lib/ApiClientImpl.java

@@ -468,7 +468,8 @@ private T handleResponse(Request request, Response response) throws IOException,
             }
 
             if (!responseContentType.is(mediaType.withoutParameters())) {
-                LOG.warn("We said we'd accept {} but got {} back, let's see how that's going to work out...", mediaType, responseContentType);
+                LOG.error("Accept header was {} but response is {}. Failing.", mediaType, responseContentType);
+                throw new APIException(request, response);
             }
             if (responseClass.equals(String.class)) {
                 return responseClass.cast(response.getResponseBody("UTF-8"));
@@ -486,7 +487,7 @@ private T handleResponse(Request request, Response response) throws IOException,
                     if (responseContentType.is(MediaType.JSON_UTF_8.withoutParameters())) {
                         result = deserializeJson(response, responseClass);
                     } else {
-                        LOG.error("Don't know how to deserialize objects with content in {}, expected {}, failing.", responseContentType, mediaType);
+                        LOG.error("Cannot deserialize content type {} expected {}, failing.", responseContentType, mediaType);
                         throw new APIException(request, response);
                     }
 
@@ -523,22 +524,47 @@ private void ensureAuthentication() {
             }
         }
 
-        private class RequestAndFuture {
+        private class RequestContext {
+            private final Node node;
             private final Request request;
             private final ListenableFuture<Response> listenableFuture;
-            public RequestAndFuture(Request request, ListenableFuture<Response> listenableFuture) {
+
+            public RequestContext(Node node, Request request, ListenableFuture<Response> listenableFuture) {
+                this.node = node;
                 this.request = request;
                 this.listenableFuture = listenableFuture;
             }
+
+            @Override
+            public boolean equals(Object o) {
+                if (this == o) return true;
+                if (o == null || getClass() != o.getClass()) return false;
+
+                RequestContext that = (RequestContext) o;
+
+                if (!node.equals(that.node)) return false;
+                if (!request.equals(that.request)) return false;
+                return listenableFuture.equals(that.listenableFuture);
+
+            }
+
+            @Override
+            public int hashCode() {
+                int result = node.hashCode();
+                result = 31 * result + request.hashCode();
+                result = 31 * result + listenableFuture.hashCode();
+                return result;
+            }
         }
+
         @Override
         public Map<Node, T> executeOnAll() throws APIException {
             HashMap<Node, T> results = Maps.newHashMap();
             if (node == null && nodes == null) {
                 nodes = serverNodes.all();
             }
 
-            final Map<Node, RequestAndFuture> requests = Maps.newHashMap();
+            final Set<RequestContext> requestContexts = Sets.newHashSetWithExpectedSize(nodes.size());
             final Collection<Response> responses = Lists.newArrayList();
 
             ensureAuthentication();
@@ -547,11 +573,11 @@ public Map<Node, T> executeOnAll() throws APIException {
                 try {
                     final AsyncHttpClient.BoundRequestBuilder requestBuilder = requestBuilderForUrl(url);
                     requestBuilder.addHeader(HttpHeaders.ACCEPT, mediaType.toString());
-                    // we need it for the APIException
 
+                    // we need to build the request in case we have to throw an APIException in handleResponse()
                     final Request request = requestBuilder.build();
                     if (LOG.isDebugEnabled()) {
-                        LOG.debug("API Request: {}", request.toString());
+                        LOG.debug("API Request: {}", request);
                     }
                     final ListenableFuture<Response> future = requestBuilder.execute(new AsyncCompletionHandler<Response>() {
                         @Override
@@ -560,7 +586,7 @@ public Response onCompleted(Response response) throws Exception {
                             return response;
                         }
                     });
-                    requests.put(currentNode, new RequestAndFuture(request, future));
+                    requestContexts.add(new RequestContext(currentNode, request, future));
                 } catch (IOException e) {
                     LOG.error("Cannot execute request", e);
                     currentNode.markFailure();
@@ -570,13 +596,13 @@ public Response onCompleted(Response response) throws Exception {
             // Set 200 OK as standard if not defined.
             ensureExpectedResponseCodes();
 
-            for (Map.Entry<Node, RequestAndFuture> nodeAndRequest : requests.entrySet()) {
-                final Node node = nodeAndRequest.getKey();
-                final ListenableFuture<Response> future = nodeAndRequest.getValue().listenableFuture;
+            for (RequestContext context : requestContexts) {
+                final Node node = context.node;
+                final ListenableFuture<Response> future = context.listenableFuture;
                 try {
                     final Response response = future.get(timeoutValue, timeoutUnit);
                     node.touch();
-                    final T result = handleResponse(nodeAndRequest.getValue().request, response);
+                    final T result = handleResponse(context.request, response);
                     results.put(node, result);
                 } catch (InterruptedException e) {
                     LOG.error("API call Interrupted", e);