I have a controller that I have written an AOP on. My controller would read something like -
#Operation(operation="foo")
#GetMapping("/abc/def")
public void getFoo() {
...
}
The corresponding #interface for Operation has been created.
My aspect looks something like -
#Before("#annotation(operation)")
public void beforeOperation(ProceedingJoinPoint pjp, Operation operation) {
Data data = restService.getData();
}
I make a HTTP call in the aspect to get data. Is there a way I can let this data be accessible to the controller without having to make that HTTP call again?
Related
I implemented a customized ScalarFunction class, I would like to initialize a hashmap which read data from a database in open() function, but it always stuck over there, so is it a right way to use open() function like this? and how many time the open() function would be invoked, just once or the same times with eval() function?
My sample code as following:
public class GenNameUDF extends ScalarFunction {
#Override
public void open(FunctionContext context) throws Exception {
super.open(context);
CommonClass.map = initMap();//here will read data from db
}
public String eval(String pubIp) {
return todo();
}
}
If the amount of data in db is small, you can use broadcast to acess db only once
Otherwise, you can build connection in open method, and access db when needed
-yt $file is also helpful.
I have a Spring controller defined like this with 2 request mappings, one using localDAO and the other using dependencyDAO. LocalDAO classes exist in my project and DependencyDAO classes are imported via maven dependency:
#RestController
#PreAuthorize("hasRole('USER')")
public class MyController
#Autowired
private localDAO LocalDAO; // dao classes exist in my project
#Autowired
private DependencyDAO dependencyDAO; // dao classes imported via maven dependency
...
#RequestMapping("/getUsingLocalDAO")
private String getUsingLocalDAO(
#JsonProperty("param") String param) {
localDAO.get(param) ... // <== this never null
}
#RequestMapping("/getUsingDependencyDAO")
private String getUsingDependencyDAO(
#JsonProperty("param") String param) {
dependencyDAO.get(param) ... // <== this always null
}
...
My dao beans are defined in another class:
#Configuration
public class DaoBeans {
#Bean
public LocalDAO localDAO() throws Exception {
return new LocalDAOImpl();
}
#Bean
public DependencyDAO dependencyDAO () throws Exception {
return new DependencyDAOImpl();
}
...
I am doing an $http.post from Angular like this:
$http.post('getUsingLocalDAO', $.param($scope.parameters), {
headers : {
"content-type" : "application/x-www-form-urlencoded"
}
}).success(function(data) {
...
}).error(function(data) {
...
$http.post('getUsingDependencyDAO', $.param($scope.parameters), {
headers : {
"content-type" : "application/x-www-form-urlencoded"
}
}).success(function(data) {
...
}).error(function(data) {
...
Both posts are identical except for the method they execute.
When stepping through the debugger I can see all the dao beans being created.
When I call getUsingLocalDAO everything works as expected.
But, when I call getUsingDependencyDAO every #Autowired object is null.
I believe I am getting different instances of MyController. One managed by Spring and one not; or at least not instantiated properly.
I make these calls in succession. It doesn't matter what order they are in.
I tried injecting the servlet context via #Autowired to get the bean manually but it is always null in getUsingDependencyDAO as well.
I tried using application context aware and although I see the context setter being set in the debugger the context is always null in getUsingDependencyDAO.
If I wrap the two calls in a third request mapping like so everything works well (no null objects).
#RequestMapping("/getUsingBothDAO")
private String getUsingBothDAO(
#JsonProperty("param") String param) {
getLocalDAO(param);
getDependencyDAO(param);
...
}
I am using Spring-Boot 4.1.5. My project is 100% annotation driven and has no .xml configurations. The only difference between the two request mappings is that one uses a bean from a dependency and one does not.
I have been searching for an answer to this problem for 3 days and have not found anything close to what I am experiencing.
Can anyone shed some light as to what I am doing wrong? Any help would be greatly appreciated.
Thanks.
Ok, I solved the problem. My example code above is not entirely accurate. The request method that was giving me nulls was defined as a private method while the one that worked was defined as public as its supposed to be. Originally the private method was not a request method and that modifier remained after the change. I changed it to public and everything is working.
It was just coincidence that the private method was from an imported project. It's curious that Spring did not throw an error that the request mapping didn't exist on the private method or something to that effect.
Thanks to anyone who looked at this and was trying to figure it out.
I know the standard way of writing an AOP advice around a controller method and that you can get access to the HttpServletRequest arg, if declared in controller method.
But my scenario is that I have a translation service, that is currently session-scoped maintaining the user's locale for translation. I feel this makes the service stateful and also I do not want it to be session-scoped, as I think it is really Singleton. But there are multiple places where the translation service methods are called and so I do not want to change the signature to add request/locale in these methods. The problem is that all the callers of the translation service's methods do not have access to HttpServletRequest (not controller methods)? Can I write an aspect around the translation service methods and somehow magically get access to HttpServletRequest regardless of whether it is available in the caller's context or not?
#Service
public class TranslationService {
public void translate(String key) {
...
}
}
#Aspect
#Component
public class LocaleFinder {
#PointCut("execution(* TranslationService.translate(..))")
private void fetchLocale() {}
#Around("fetchLocale()") // in parameter list
public void advice(JoinPoint joinpoint, HttpServletRequest request) { .... }
}
If now, the caller of translate does not have HttpServletRequest, can't I get request in the advice? Is there a workaround?
Can I write an aspect around the translation service methods and
somehow magically get access to HttpServletRequest regardless of
whether it is available in the caller's context or not?
Not easily. Actually, it would require a lot of effort.
The easy way to do it is to rely on RequestContextHolder. In every request, the DispatcherServlet binds the current HttpServletRequest to a static ThreadLocal object in the RequestContextHolder. You can retrieve it when executing within the same Thread with
HttpServletRequest request = ((ServletRequestAttributes) RequestContextHolder.currentRequestAttributes()).getRequest();
You can do this in the advice() method and therefore don't need to declare a parameter.
You should be able to auto-wire a HttpServletRequest in your aspect. Spring provides a proxy to the current thread local request instance that way.
So just add:
#Autowired private HttpServletRequest request;
to your aspect. Better yet is to use constructor injection.
I'm trying to put together my first Akka/Camel application from "scratch" (read, "noob") using the following lib versions:
akka-camel: 2.2.0-RC1
According to all of the documentation I can find (Akka docs, user groups, etc.) all I have to do to consume from a file-based queue is set up my system this way:
Main class:
actorSystem = ActorSystem.create("my-system");
Props props = new Props(Supervisor.class);
ActorRef supervisor = actorSystem.actorOf(props, "supervisor");
Camel camel = CamelExtension.get(actorSystem);
CamelContext camelContext = camel.context();
camelContext.start();
Supervisor class:
import akka.actor.ActorRef;
import akka.actor.Props;
import akka.camel.javaapi.UntypedConsumerActor;
import org.apache.camel.Message;
/**
* Manages creation and supervision of UploadBatchWorkers.
*/
public class Supervisor extends UntypedConsumerActor {
#Override
public String getEndpointUri() {
return "file:///Users/myhome/queue";
}
#Override
public void preStart() {
String test = "test";
}
#Override
public void onReceive(Object message) {
if (message instanceof CamelMessage) {
// do something
}
}
My problem is that even though I know the supervisor object is being created and breaks during debugging on the preStart() method's "test" line (not to mention that if I explicitly "tell" it something it processes fine), it does not consume from the defined endpoint, even though I have another application producing messages to the same endpoint.
Any idea what I'm doing wrong?
Ok, the problem was my own fault and is clearly visible in the example code if you look at the Consumer trait from which the UntypedConsumerActor inherits.
This method:
#Override
public void preStart() {
String test = "test";
}
overrides its parent's preStart() method, right? Well, that parent method is actually the one that registers the consumer with the on-the-fly created endpoint, so while you can override it, you must call super() or it will not work.
Hope this is useful to someone down the road!
Try changing your instanceof inside of onReceive to this:
if (message instanceof CamelMessage){
//do processing here
}
Where CamelMessage is from package akka.camel. That's what the examples in the akka camel docs are doing.
I am new to rhino mocks and unit testing in general. I am starting to write some tests for my wpf mvvm app. Here is a sample scenario I am trying to test:
The view model:
List<DataItems> _theData = new List<DataItems>();
public MyViewModel(IServer server)
{
_server = server;
InitializeData();
}
private void InitializeData()
{
_server.GetData(MyCallback);
}
private void MyCallback()
{
_theData = _server.TheData;
}
public List<DataItems> VMData
{
get
{
return _theData;
}
}
Server:
public List<DataItems> TheData
{
get
{
return _cachedData;
}
}
public void GetData(Action callBack)
{
//Populate cached data
...
if(callBack != null)
{
callBack();
}
}
In my test, I want to verify that viewModel.VMData.Count == server.TheData.Count. I tried using rhino mocks to stub the server, pre-poulating TheData with some values. The I called the view model constructor, and then tried to compare the counts.
My problem is that I do not know how to get my server to actually call back into my view model. After the vm constructor is called, InitializeData() is called as expected but the stub server's GetData call is not made.
How can I make this simple test work?
if you are stubbing IServer and expecting that the calling a method on the stub will invoke the implementation in your concrete class, that is your misconception. the GetData method on the stub instance will only return what you tell it to, and not execute any code in the concrete dependency. remember that the only thing your stub IServer object has in common with your concrete implemetation of IServer is that they both implement IServer. expecting that the side effects in the method in your concrete implemenation will happen when calling the method on the stub is just faulty.
as to how to make it work: there's not really a good way to do this test as you are stating with the design of these classes as is. you are trying to test that a side effect occurred in the dependency that you are stubbing out of participation. to really test what you want here and if you want to keep these classes with this relationship, i'd suggest that you don't mock server at all and use the real object. redesign the server so that it depends on another component that loads from the cache so you can stub that thing instead.