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Jersey + Grizzly Http Container + shared ServiceLocator + custom Worker Thread Pool

I need to change the thread pool of the underlying Grizzly transport layer.
According to the docs of GrizzlyHttpServerFactory:
Should you need to fine tune the underlying Grizzly transport layer, you can obtain direct access to the corresponding Grizzly structures with server.getListener("grizzly").getTransport().
and
To make certain options take effect, you need to work with an inactive HttpServer instance (that is the one that has not been started yet). To obtain such an instance, use one of the below factory methods with start parameter set to false
Since I like to put my self in the worse situations :-) the method I need shuld be:
HttpServer server= GrizzlyHttpServerFactory
.createHttpServer(getURI(), this.config, serviceLocator, false);
but the only method available (nearest to my case) is:
public static HttpServer createHttpServer(final URI uri,
final GrizzlyHttpContainer handler, final boolean secure,
final SSLEngineConfigurator sslEngineConfigurator, final boolean start) {
//....
}
If I understand the GrizzlyHttpContainer is private so I should use:
GrizzlyHttpContainer httpContainer =
new GrizzlyHttpContainerProvider().createContainer(GrizzlyHttpContainer.class, config);
But, since I'm sharing a ServiceLocator between resources and internal classes (a couple of ActiveMQ subscribers). I wonder if it were possible to achieve something like this:
GrizzlyHttpContainer httpContainer =
new GrizzlyHttpContainerProvider()
.createContainer(GrizzlyHttpContainer.class, configuration, serviceLocator);
Ideally what i need is a method like this:
public class GrizzlyHttpContainerProvider implements ContainerProvider {
#Override
public <T> T createContainer(Class<T> type, Application application, Object parentContext) throws ProcessingException {
if (HttpHandler.class == type || GrizzlyHttpContainer.class == type) {
return type.cast(new GrizzlyHttpContainer(application, parentContext));
}
return null;
}
}
Any suggestion about how to achieve this?
I'd would prefer a cleaner solution then creating the server with one of the provided methods that (for my case) auto start the server. Then stop it (waiting for termination somehow) and then finally:
this.server.getListener("grizzly").getTransport().setWorkerThreadPool(....);
and restarting it.
Best Regards,
Luca
Edit
This is cheating :-) ... this is the "dark way" (don't do it at home):
private GrizzlyHttpContainer getGrizzlyHttpContainer(final Application application,
final Object context) {
try {
Class<?> cls = Class.forName(
"org.glassfish.jersey.grizzly2.httpserver.GrizzlyHttpContainer");
Constructor<?> cons = cls.getDeclaredConstructor(Application.class, Object.class);
//System.out.println("Constructor Name--->>>"+cons.getName());
cons.setAccessible(true);
return (GrizzlyHttpContainer)cons.newInstance(application, context);
} catch (Exception err) {
return null;
}
}

Is there a nice way to access Guice Request scoped items from child threads and scope things locally to those threads? [duplicate]

I am using Guice's RequestScoped and Provider in order to get instances of some classes during a user request. This works fine currently. Now I want to do some job in a background thread, using the same instances created during request.
However, when I call Provider.get(), guice returns an error:
Error in custom provider, com.google.inject.OutOfScopeException: Cannot
access scoped object. Either we are not currently inside an HTTP Servlet
request, or you may have forgotten to apply
com.google.inject.servlet.GuiceFilter as a servlet
filter for this request.
afaik, this is due to the fact that Guice uses thread local variables in order to keep track of the current request instances, so it is not possible to call Provider.get() from a thread different from the thread that is handling the request.
How can I get the same instances inside new threads using Provider? It is possible to achieve this writing a custom scope?

I recently solved this exact problem. There are a few things you can do. First, read up on ServletScopes.continueRequest(), which wraps a callable so it will execute as if it is within the current request. However, that's not a complete solution because it won't forward #RequestScoped objects, only basic things like the HttpServletResponse. That's because #RequestScoped objects are not expected to be thread safe. You have some options:
If your entire #RequestScoped hierarchy is computable from just the HTTP response, you're done! You will get new instances of these objects in the other thread though.
You can use the code snippet below to explicitly forward all RequestScoped objects, with the caveat that they will all be eagerly instantiated.
Some of my #RequestScoped objects couldn't handle being eagerly instantiated because they only work for certain requests. I extended the below solution with my own scope, #ThreadSafeRequestScoped, and only forwarded those ones.
Code sample:
public class RequestScopePropagator {
private final Map<Key<?>, Provider<?>> requestScopedValues = new HashMap<>();
#Inject
RequestScopePropagator(Injector injector) {
for (Map.Entry<Key<?>, Binding<?>> entry : injector.getAllBindings().entrySet()) {
Key<?> key = entry.getKey();
Binding<?> binding = entry.getValue();
// This is like Scopes.isSingleton() but we don't have to follow linked bindings
if (binding.acceptScopingVisitor(IS_REQUEST_SCOPED)) {
requestScopedValues.put(key, binding.getProvider());
}
}
}
private final BindingScopingVisitor<Boolean> IS_REQUEST_SCOPED = new BindingScopingVisitor<Boolean>() {
#Override
public Boolean visitScopeAnnotation(Class<? extends Annotation> scopeAnnotation) {
return scopeAnnotation == RequestScoped.class;
}
#Override
public Boolean visitScope(Scope scope) {
return scope == ServletScopes.REQUEST;
}
#Override
public Boolean visitNoScoping() {
return false;
}
#Override
public Boolean visitEagerSingleton() {
return false;
}
};
public <T> Callable<T> continueRequest(Callable<T> callable) {
Map<Key<?>, Object> seedMap = new HashMap<>();
for (Map.Entry<Key<?>, Provider<?>> entry : requestScopedValues.entrySet()) {
// This instantiates objects eagerly
seedMap.put(entry.getKey(), entry.getValue().get());
}
return ServletScopes.continueRequest(callable, seedMap);
}
}

I have faced the exact same problem but solved it in a different way. I use jOOQ in my projects and I have implemented transactions using a request scope object and an HTTP filter.
But then I created a background task which is spawned by the server in the middle of the night. And the injection is not working because there is no request scope.
Well. The solutions is simple: create a request scope manually. Of course there is no HTTP request going on but that's not the point (mostly). It is the concept of the request scope. So I just need a request scope that exists alongside my background task.
Guice has an easy way to create a request scope: ServletScope.scopeRequest.
public class MyBackgroundTask extends Thread {
#Override
public void run() {
RequestScoper scope = ServletScopes.scopeRequest(Collections.emptyMap());
try ( RequestScoper.CloseableScope ignored = scope.open() ) {
doTask();
}
}
private void doTask() {
}
}
Oh, and you probably will need some injections. Be sure to use providers there, you want to delay it's creation until inside the created scope.

Better use ServletScopes.transferRequest(Callable) in Guice 4

alternative to instanceof operator when specifying mocks for multiple web services

I am writing endpoint unit tests and for most of those there is an external web service that should be mocked, or a couple of them.
At first, i was creating mocks within tests which was okay when an endpoint test used only one external service, the mock creation was basically one liner.
As use cases became more complex, i needed to mock couple of services and exceptions for a single endpoint test.
I have put these mocks creation behind factories that all extend single factory and used builder pattern.
Within that base factory there is an inner class which i used as a builder for MockWebServiceServer.
protected class MultiStepMockBuilder {
private List<Object> mockActions = new ArrayList<Object>();
private WebServiceGatewaySupport gatewaySupport;
protected MultiStepMockBuilder(WebServiceGatewaySupport gatewaySupport) {
this.gatewaySupport = gatewaySupport;
}
protected MultiStepMockBuilder exception(RuntimeException exception) {
mockActions.add(exception);
return this;
}
protected MultiStepMockBuilder resource(Resource resource) {
mockActions.add(resource);
return this;
}
protected MockWebServiceServer build() {
MockWebServiceServer server = MockWebServiceServer.createServer(gatewaySupport);
for(Object mock: mockActions) {
if (mock instanceof RuntimeException) {
server.expect(anything()).andRespond(withException((RuntimeException)mock));
}
else if (mock instanceof Resource)
{
try
{
server.expect(anything()).andRespond(withSoapEnvelope((Resource) mock));
} catch (IOException e) {e.printStackTrace();}
}
else
throw new RuntimeException("unusuported mock action");
}
return server;
}
}
}
So i can now do something like this to create mock:
return new MultiStepMockBuilder(gatewaySupport).resource(success).exception(new WebServiceIOException("reserve timeout"))
.resource(invalidMsisdn)
.build();
The issue i have with this implementation is dependence on instanceof operator which i never use outside of equals.
Is there an alternative way to instanceof operator in this scenario ? From the questions on topic of instanceof everybody argues it should only be used within equals and therefore i have feeling that this is 'dirty' solution.
Is there an alternative to instanceof operator, within Spring or as a different design, while keeping fluent interface for mocks creation ?

I don't know Spring well enough to comment specifically on this particular area, but to me, this just seems like a design thing. Generally, when you are faced with using instanceof, it means that you need to know the type, but you don't have the type. It is generally the case that we might need to refactor in order to achieve a more cohesive design that avoids this kind of problem.
The root of where the type information is being lost, is in the List of mock actions, which are currently just being stored as a List of Objects. One way to help with this then, is to look at the type of the List and consider if there is a better type that could be stored in the List that might help us later. So we might end up with a refactoring something like this.
private List<MockAction> mockActions = new ArrayList<MockAction>();
Of course, then we have to decide what a MockAction actually is, as we've just made it up. Maybe something like this:
interface MockAction {
void performAction(MockWebServiceServer server);
}
So, we've just created this MockAction interface, and we've decided that instead of the caller performing the action - we're going to pass the server into it and ask the MockAction to perform itself. If we do this, then there will be no need for instanceof - because particular types of MockActions will know what they contain.
So, what types of MockActions do we need?
class ExceptionAction implements MockAction {
private final Exception exception;
private ExceptionAction(final Exception exception) {
this.exception = exception;
}
public void performAction(final MockWebServiceServer server) {
server.expect(anything()).andRespond(withException(exception);
}
}
class ResourceAction implements MockAction {
private final Resource resource;
private ResourceAction(final Resource resource) {
this.resource = resource;
}
public void performAction(final MockWebServiceServer server) {
/* I've left out the exception handling */
server.expect(anything()).andRespond(withSoapEnvelope(resource));
}
}
Ok, so now we've gotten to this point, there are a couple of loose ends.
We're still adding exceptions to the list of MockActions - but we need to change the add methods to make sure we put the right thing in the list. The new versions of these methods might look something like this:
protected MultiStepMockBuilder exception(RuntimeException exception) {
mockActions.add(new ExceptionAction(exception));
return this;
}
protected MultiStepMockBuilder resource(Resource resource) {
mockActions.add(new ResourceAction(resource));
return this;
}
So, now we've left our interface the same, but we're wrapping the resource or exception as they're added to the list so that we have the type specificity we need later on.
And then finally, we need to refactor our method that actually makes the calls, which now looks something like this - which is much simpler and cleaner.
protected MockWebServiceServer build() {
MockWebServiceServer server = MockWebServiceServer.createServer(gatewaySupport);
for(MockAction action: mockActions) {
action.performAction(server);
}
return server;
}

Implementing GWT RequestFactory service for non-entity requests

I have the following Java servlet that performs what I call the "Addition Service":
public class AdditionService extends HttpServlet {
#Override
public void doGet(HttpServletRequest request, HttpServletResponse response) {
// The request will have 2 Integers inside its body that need to be
// added together and returned in the response.
Integer addend = extractAddendFromRequest(request);
Integer augend = extractAugendFromRequest(request);
Integer sum = addend + augend;
PrintWriter writer = response.getWriter();
writer.write(sum);
}
}
I am trying to get GWT's RequestFactory to do the same thing (adding two numbers on the app server and returning the sum as a response) using a ValueProxy and AdditionService, and am running into a few issues.
Here's the AdditionRequest (client tier) which is a value object holding two Integers to be added:
// Please note the "tier" (client, shared, server) I have placed all of my Java classes in
// as you read through the code.
public class com.myapp.client.AdditionRequest {
private Integer addend;
private Integer augend;
public AdditionRequest() {
super();
this.addend = 0;
this.augend = 0;
}
// Getters & setters for addend/augend.
}
Next my proxy (client tier):
#ProxyFor(value=AdditionRequest.class)
public interface com.myapp.client.AdditionRequestProxy extends ValueProxy {
public Integer getAddend();
public Integer getAugend();
public void setAddend(Integer a);
public void setAugend(Integer a);
}
Next my service API (in the shared tier):
#Service(value=DefaultAdditionService.class)
public interface com.myapp.shared.AdditionService extends RequestContext {
Request<Integer> sum(AdditionRequest request);
}
Next my request factory (shared tier):
public class com.myapp.shared.ServiceProvider implements RequestFactory {
public AdditionService getAdditionService() {
return new DefaultAdditionService();
}
// ... but since I'm implementing RequestFactory, there's about a dozen
// other methods GWT is forcing me to implement: find, getEventBus, fire, etc.
// Do I really need to implement all these?
}
Finally where the magic happens (server tier):
public class com.myapp.server.DefaultAdditionService implements AdditionService {
#Override
public Request<Integer> sum(AdditionRequest request) {
Integer sum = request.getAddend() + request.getAugend();
return sum;
}
// And because AdditionService extends RequestContext there's another bunch of
// methods GWT is forcing me to implement here: append, create, isChanged, etc.
// Do I really need to implement all these?
}
Here are my questions:
Is my "tier" strategy correct? Have I packaged all the types in the correct client/shared/server packages?
I don't think my setup is correct because AdditionService (in shared) references DefaultAdditionService, which is on the server, which it shouldn't be doing. Shared types should be able to live both on the client and the server, but not have dependencies on either...
Should ServiceProvider be a class that implements RequestFactory, or should it be an interface that extends it? If the latter, where do I define the ServiceProvider impl, and how do I link it back to all these other classes?
What about all these methods in ServiceProvider and DefaultAdditionService? Do I need to implement all 20+ of these core GWT methods? Or am I using the API incorrectly or not as simply as I could be using it?
Where does service locator factor in here? How?

If you want to use RF as a simple RPC mechanism [*] you can (and you are right: only ValueProxys), but you need something more: ServiceLocators (i.e., GWT 2.1.1).
With ServiceLocator you can simply put your service implementation (like your servlet) into a real service instance, instead into an entity object (as you will use only ValueProxys, with no static getXyz() methods) as required by the RF protocol. Note the existence also of Locators, used to externalize all those methods from your server-side entities: not needed if you use ValueProxy everywhere.
A ServiceLocator looks something like (taken from official docs):
public class DefaultAdditionServiceLocator implements ServiceLocator {
#Override
public Object getInstance(Class<?> clazz) {
try {
return clazz.newInstance();
} catch (InstantiationException e) {
throw new RuntimeException(e);
} catch (IllegalAccessException e) {
throw new RuntimeException(e);
}
}
}
You need to annotate your DefaultAdditionService also with a locator param, so RF knows on what to rely when it comes to dispatch your request to your service. Something like:
#Service(value = DefaultAdditionService.class, locator = DefaultAdditionServiceLocator.class)
public interface com.myapp.shared.AdditionService extends RequestContext {
// Note here, you need to use the proxy type of your AdditionRequest.
Request<Integer> sum(AdditionRequestProxy request);
}
Your service will then be the simplest possible thing on Earth (no need to extend/implement anything RF-related):
public class com.myapp.server.DefaultAdditionService {
// The server-side AdditionRequest type.
public Integer sum(AdditionRequest request) {
Integer sum = request.getAddend() + request.getAugend();
return sum;
}
}
If you mispell sum() or you do not implement a method declared in your RequestContext you will get an error.
To instantiate RequestContexts you need to extend the RequestFactory interface, with a public factory method for com.myapp.shared.AdditionService. Something like:
public interface AdditionServiceRequestFactory extends RequestFactory {
public com.myapp.shared.AdditionService createAdditionServiceRequestContext();
}
All your client calls will start from this. See the docs, if not already.
Now, RF works by totally separating the objects your want to pass from client (using EntityProxy and ValueProxy) and server (the real objects, either Entity values or simple DTO classes). You will use proxy types (i.e., interfaces whom implementations are automatically generated) everywhere in client/shared tier, and you use the relative domain object (the one referenced with #ProxyFor) only on server side. RF will take care of the rest. So your AdditionRequest will be on your server side, while AdditionRequestProxy will be on your client side (see the note in the RequestContext). Also note that, if you simply use primitive/boxed types as your RequestContext params or return types, you will not even need to create ValueProxys at all, as they are default transportable.
The last bit you need, is to wire the RequestFactoryServlet on your web.xml. See the docs here. Note that you can extend it if you want to, say, play around with custom ExceptionHandlers or ServiceLayerDecorators, but you don't need to.
Speaking about where to put everything:
Locators, ServiceLocators, service instances, domain objects, and RequestFactoryServlet extensions, will be on your server-side;
The RequestContext, RequestFactory extensions and all your proxy types will be on the shared-side;
client side will initialize the RequestFactory extension and use it to obtain the factory instance for your service requests.
All in all... to create a simple RPC mechanism with RF, just:
create your service along with ServiceLocator;
create a RequestContext for your requests (annotated with service and locator values);
create a RequestFactory extension to return your RequestContext;
if you want to use more than primitive types in your RequestContext (like simple DTOs), just create client proxy interfaces for them, annotated with #ProxyFor, and remember where to use each type;
wire everything.
Much like that. Ok, I wrote too much and probably forgot something :)
For reference, see:
Official RF documentation;
Thomas Broyer's articles [1], [2];
RF vs GWT-RPC from the RF author point of view.
[*]: In this approach you shift your logic from data-oriented to service-oriented app. You give up using Entitys, IDs, versions and, of course, all the complex diff logic between client and server, when it comes to CRUD operations.

spring two-way rmi callback from server executing on client side

On the server-side I have a ListenerManager which fires callbacks to its Listeners. The manager is exported using a Spring RmiServiceExporter
On the client-side I have a proxy to the manager created by an RmiProxyFactoryBean, and a Listener implementation registered through this proxy with the manager on the server side.
So far so good: the ListenerManager is given a Listener and it invokes its callbacks, however since the listener is just a deserialized copy of the client-side object, the callback runs on the server side, not the client side.
How can I get Spring to generate a proxy on the server-side to the client-side listener so that the callback invoked by the server is executed remotely on the client-side? Surely I don't need another (exporter, proxy factory) pair in the opposite direction?

A pure RMI solution: the client-side listener object needs to implement java.rmi.server.UnicastRemoteObject. If it does, and each of its methods throw RemoteException then when it is passed to the server through the manager proxy everything is wired up automatically, and method invocations on the server-side proxy to this listener are remote invocations of methods on the real client-side object.
This will do, but it's even better to be able to wrap the object for export without requiring a particular superclass. We can use a CGLIB Enhancer to "proxy" the listener as a subclass of UnicastRemoteObject that also implements the service interfaces. This still requires that the target object implement java.rmi.Remote and declare throws RemoteException.
Next step is a solution that can export arbitrary objects for remote invocation of their methods, without requiring that they implement Remote or declare throws RemoteException. We must integrate this proxying with the existing Spring infrastructure, which we can do with a new implementation of RmiBasedExporter modelled on the non-registry bits of RmiServiceExporter#prepare() to export the RMI stub of our proxy and on the invocation part of RmiClientInterceptor.doInvoke(MethodInvocation, RmiInvocationHandler). We need to be able to get hold of an exported proxy instance of our service interfaces. We can model this on the means used by Spring to apparently "export" non-RMI interfaces. Spring proxies the interface to generate a RmiInvocationWrapper for invocation of a non-RMI method, serialises the method details and arguments, then invokes this on the far side of the RMI connection.
Use a ProxyFactory and an RmiInvocationHandler implementation to proxy the target object.
Use a new implementation of RmiBasedExporter to getObjectToExport(), and export it using UnicastRemoteObject#export(obj, 0).
For the invocation handler, rmiInvocationHandler.invoke(invocationFactory.createRemoteInvocation(invocation)), with a DefaultRemoteInvocationFactory.
Handle exceptions and wrap appropriately to avoid seeing UndeclaredThrowableExceptions.
So, we can use RMI to export arbitrary objects. This means we can use one of these objects on the client-side as a parameter to an RMI method call on an RMI server-side object, and when the deserialised stub on the server-side has methods invoked, those methods will execute on the client-side. Magic.

Following Joe Kearney's explaination, I have created my RMIUtil.java. Hope there is nothing left.
BTW, please ref this
for "java.rmi.NoSuchObjectException: no such object in table"

Just add some code to Joe's answer.
Extends RmiServiceExporter and get access to exported object:
public class RmiServiceExporter extends org.springframework.remoting.rmi.RmiServiceExporter {
private Object remoteService;
private String remoteServiceName;
#Override
public Remote getObjectToExport() {
Remote exportedObject = super.getObjectToExport();
if (getService() instanceof Remote && (
getServiceInterface() == null || exportedObject.getClass().isAssignableFrom(getServiceInterface()))) {
this.remoteService = exportedObject;
}
else {
// RMI Invokers.
ProxyFactory factory = new ProxyFactory(getServiceInterface(),
new RmiServiceInterceptor((RmiInvocationHandler) exportedObject, remoteServiceName));
this.remoteService = factory.getProxy();
}
return exportedObject;
}
public Object getRemoteService() {
return remoteService;
}
/**
* Override to get access to the serviceName
*/
#Override
public void setServiceName(String serviceName) {
this.remoteServiceName = serviceName;
super.setServiceName(serviceName);
}
}
The interceptor used in the proxy (the remote service callback):
public class RmiServiceInterceptor extends RemoteInvocationBasedAccessor
implements MethodInterceptor, Serializable {
private RmiInvocationHandler invocationHandler;
private String serviceName;
public RmiServiceInterceptor(RmiInvocationHandler invocationHandler) {
this(invocationHandler, null);
}
public RmiServiceInterceptor(RmiInvocationHandler invocationHandler, String serviceName) {
this.invocationHandler = invocationHandler;
this.serviceName = serviceName;
}
/**
* {#inheritDoc}
*/
public Object invoke(MethodInvocation invocation) throws Throwable {
try {
return invocationHandler.invoke(createRemoteInvocation(invocation));
}
catch (RemoteException ex) {
throw RmiClientInterceptorUtils.convertRmiAccessException(
invocation.getMethod(), ex, RmiClientInterceptorUtils.isConnectFailure(ex),
extractServiceUrl());
}
}
/**
* Try to extract service Url from invationHandler.toString() for exception info
* #return Service Url
*/
private String extractServiceUrl() {
String toParse = invocationHandler.toString();
String url = "rmi://" + StringUtils.substringBefore(
StringUtils.substringAfter(toParse, "endpoint:["), "]");
if (serviceName != null)
url = StringUtils.substringBefore(url, ":") + "/" + serviceName;
return url;
}
}
When exporting the service with this RmiServiceExporter, we cand send a rmi callback with:
someRemoteService.someRemoteMethod(rmiServiceExporter.getRemoteService());