I have a springframework application in which I would like to add a transaction listener to a transaction which is currently in progress. The motivation is to trigger a post commit action which notifies downstream systems. I am using #Transactional to wrap a transaction around some service method -- which is where I want to create/register the post transaction listener. I want to do something "like" the following.
public class MyService {
#Transaction
public void doIt() {
modifyObjects();
// something like this
getTransactionManager().registerPostCommitAction(new
TransactionSynchronizationAdapter() {
public void afterCommit() {
notifyDownstream();
}
});
}
}
Spring has a TransactionSynchronization interface and adapter class which seems exactly what I want; however it is not immediately clear how to register one dynamically with either the current transaction, or the transaction manager. I would rather not subclass JtaTransactionManager if I can avoid it.
Q: Has anyone done this before.
Q: what is the simplest way to register my adapter?
Actually it was not as hard as I thought; spring has a static helper class that puts the 'right' stuff into the thread context.
TransactionSynchronizationManager.registerSynchronization(
new TransactionSynchronizationAdapter() {
#Override
public void afterCommit() {
s_logger.info("TRANSACTION COMPLETE!!!");
}
}
);
you could use an aspect to match transactional methods aspect in your service to accomplish this:
#Aspect
public class AfterReturningExample {
#AfterReturning("execution(* com.mypackage.MyService.*(..))")
public void afterReturning() {
// ...
}
}
Here is a more complete solution I did for a similar problem that with wanting my messages sent after transactions are committed (I could have used RabbitMQ TX but they are rather slow).
public class MessageBusUtils {
public static Optional<MessageBusResourceHolder> getTransactionalResourceHolder(TxMessageBus messageBus) {
if ( ! TransactionSynchronizationManager.isActualTransactionActive()) {
return Optional.absent();
}
MessageBusResourceHolder o = (MessageBusResourceHolder) TransactionSynchronizationManager.getResource(messageBus);
if (o != null) return Optional.of(o);
o = new MessageBusResourceHolder();
TransactionSynchronizationManager.bindResource(messageBus, o);
o.setSynchronizedWithTransaction(true);
if (TransactionSynchronizationManager.isSynchronizationActive()) {
TransactionSynchronizationManager.registerSynchronization(new MessageBusResourceSynchronization(o, messageBus));
}
return Optional.of(o);
}
private static class MessageBusResourceSynchronization extends ResourceHolderSynchronization<MessageBusResourceHolder, TxMessageBus> {
private final TxMessageBus messageBus;
private final MessageBusResourceHolder holder;
public MessageBusResourceSynchronization(MessageBusResourceHolder resourceHolder, TxMessageBus resourceKey) {
super(resourceHolder, resourceKey);
this.messageBus = resourceKey;
this.holder = resourceHolder;
}
#Override
protected void cleanupResource(MessageBusResourceHolder resourceHolder, TxMessageBus resourceKey,
boolean committed) {
resourceHolder.getPendingMessages().clear();
}
#Override
public void afterCompletion(int status) {
if (status == TransactionSynchronization.STATUS_COMMITTED) {
for (Object o : holder.getPendingMessages()) {
messageBus.post(o, false);
}
}
else {
holder.getPendingMessages().clear();
}
super.afterCompletion(status);
}
}
}
public class MessageBusResourceHolder extends ResourceHolderSupport {
private List<Object> pendingMessages = Lists.newArrayList();
public void addMessage(Object message) {
pendingMessages.add(message);
}
protected List<Object> getPendingMessages() {
return pendingMessages;
}
}
Now in your class where you actually send the message you will do
#Override
public void postAfterCommit(Object o) {
Optional<MessageBusResourceHolder> holder = MessageBusTxUtils.getTransactionalResourceHolder(this);
if (holder.isPresent()) {
holder.get().addMessage(o);
}
else {
post(o, false);
}
}
Sorry for the long winded coding samples but hopefully that will show someone how to do something after a commit.
Does it make sense to override the transaction manager on the commit and rollback methods, calling super.commit() right at the beginning.
Related
Has anyone succesfully used the CXF HttpConduitFeature for DOSGi ?
Looking at the CXF code for HttpConduitFeature.java
public class HttpConduitFeature extends DelegatingFeature<HttpConduitFeature.Portable> {
public HttpConduitFeature() {
super(new Portable());
}
public void setConduitConfig(HttpConduitConfig conduitConfig) {
delegate.setConduitConfig(conduitConfig);
}
public static class Portable implements AbstractPortableFeature {
private HttpConduitConfig conduitConfig;
#Override
public void initialize(Client client, Bus bus) {
Conduit conduit = client.getConduit();
if (conduitConfig != null && conduit instanceof HTTPConduit) {
conduitConfig.apply((HTTPConduit)conduit);
}
}
public void setConduitConfig(HttpConduitConfig conduitConfig) {
this.conduitConfig = conduitConfig;
}
}
}
And this method from the class JAXRSClientFactoryBean.java
protected void applyFeatures(AbstractClient client) {
if (getFeatures() != null) {
getFeatures().forEach(feature -> {
feature.initialize(client.getConfiguration(), getBus());
});
}
}
Which is what happens from the RsProvider-class in CXF-DOSGi, I don't understand how the initialize() from the HttpConduitFeature.Portable class will ever get called..
I tried to create my own implementation, a copy from HttpConduitFeature, but with an override of the method initialize(final InterceptorProvider interceptorProvider, final Bus bus), but then I have nothing to add the conduitConfig to. I don't see how I can make progress here.
Anyone has a better idea to add a Basic Authentication AuthorizationPolicy to my DOSGi client ? This was my attempt :
public class BasicAuthorizationIntent implements IntentsProvider {
#Override
public List<?> getIntents() {
HttpConduitConfig conduitConfig = new HttpConduitConfig();
conduitConfig.setAuthorizationPolicy(basicAuthorization());
HttpConduitFeature conduitFeature = new HttpConduitFeature();
conduitFeature.setConduitConfig(conduitConfig);
return Arrays.asList((Object) conduitFeature);
}
private AuthorizationPolicy basicAuthorization() {
AuthorizationPolicy authorizationPolicy = new AuthorizationPolicy();
authorizationPolicy.setUserName("dosgi");
authorizationPolicy.setPassword("dosgi");
authorizationPolicy.setAuthorizationType("Basic");
return authorizationPolicy;
}
}
I'm a beginner with Simple Injector and have a scenario where I need help to implement. I will try to simplify what I need to do.
I have a WebAPI where I need to authenticate users and based on the type of user choose an implementation.
Consider this structure
public interface ICarRepository {
void SaveCar(Car car);
}
//Some implementation for ICarRepository
public interface ICarLogic {
void CreateCar(Car car);
}
public class CarLogicStandard: ICarLogic {
private ICarRepository _carRepository;
public CarLogicStandard(ICarRepository carRepository) {
_carRepository = carRepository;
}
public void CreateCar(Car car) {
car.Color = "Blue";
_carRepository.SaveCar();
//Other stuff...
}
}
public class CarLogicPremium: ICarLogic {
private ICarRepository _carRepository;
public CarLogicPremium(ICarRepository carRepository) {
_carRepository = carRepository;
}
public void CreateCar(Car car) {
car.Color = "Red";
_carRepository.SaveCar();
//Other stuff 2...
}
}
And now I have a controller
public class CarController: ApiController {
private ICarLogic _carLogic;
public CarController(ICarLogic carLogic) {
_carLogic = carLogic;
}
public void Post(somePostData) {
//Identify the user based on post data
//....
Car car = somePostData.SomeCar();
_carLogic.CreateCar(car);
}
}
The code above will not work because in my request I need to identify the user. If it is a premium user the controller should use the CarLogicPremium and if it is a standard user the controller should use the CarLogicStandard.
I can configure the repository and others interfaces that don't need this logic on Global.asax however, since this case I need the request to decide which implementation should be used, I supose that I need to solve this in some other way.
There is a "Simple Injector" way to handle this? Or should I try another approach?
The simplest solution would be to configure the decision in the composition root, along with the rest of the container's configuration:
protected void Application_Start()
{
GlobalConfiguration.Configure(WebApiConfig.Register);
var container = new Container();
container.Register<CarLogicStandard>();
container.Register<CarLogicPremium>();
container.RegisterPerWebRequest<ICarRepository, CarRepository>();
container.Register<ICarLogic>(
() =>
HttpContext.Current != null &&
HttpContext.Current.User != null &&
HttpContext.Current.User.IsInRole("Premium")
? (ICarLogic)container.GetInstance<CarLogicPremium>()
: (ICarLogic)container.GetInstance<CarLogicStandard>()
);
// This is an extension method from the integration package.
container.RegisterWebApiControllers(GlobalConfiguration.Configuration);
container.Verify();
GlobalConfiguration.Configuration.DependencyResolver =
new SimpleInjectorWebApiDependencyResolver(container);
}
You could also create an abstraction over the current user and decorate standard features with premium features
public class CarLogicPremium : ICarLogic
{
private readonly ICarLogic decorated;
private readonly ICurrentUser currentUser;
private readonly ICarRepository carRepository;
public CarLogicPremium(
ICarLogic decorated,
ICurrentUser currentUser,
ICarRepository carRepository)
{
this.decorated = decorated;
this.currentUser = currentUser;
this.carRepository = carRepository;
}
public void CreateCar(Car car)
{
if (currentUser.IsPremiumMember)
{
car.Color = "Red";
this.carRepository.SaveCar(car);
//Other stuff 2...
}
else
{
this.decorated.CreateCar(car);
}
}
}
which would be configured a bit like this
protected void Application_Start()
{
GlobalConfiguration.Configure(WebApiConfig.Register);
var container = new Container();
container.Register<ICurrentUser, HttpCurrentUserProxy>();
container.RegisterPerWebRequest<ICarRepository, CarRepository>();
container.Register<ICarLogic, CarLogicStandard>();
container.RegisterDecorator(typeof(ICarLogic), typeof(CarLogicPremium));
container.RegisterWebApiControllers(GlobalConfiguration.Configuration);
container.Verify();
GlobalConfiguration.Configuration.DependencyResolver =
new SimpleInjectorWebApiDependencyResolver(container);
}
But it really depends how many variations of services you will be creating over time. If you will be constantly adding new premium features you should look to implement a variation of the Try-X pattern. Let me know if one of the above works for you or if you need more info ...
Hi My thread class is showing null pointer exception please help me to resolve
#Component
public class AlertsToProfile extends Thread {
public final Map<Integer, List<String>> userMessages = Collections.synchronizedMap(new HashMap<Integer, List<String>>());
#Autowired
ProfileDAO profileDAO;
private String categoryType;
private String dataMessage;
public String getCategoryType() {
return categoryType;
}
public void setCategoryType(String categoryType) {
this.categoryType = categoryType;
}
public String getDataMessage() {
return dataMessage;
}
public void setDataMessage(String dataMessage) {
this.dataMessage = dataMessage;
}
public void run() {
String category=getCategoryType();
String data= getDataMessage();
List<Profile> all = profileDAO.findAll();
if (all != null) {
if (category == "All" || category.equalsIgnoreCase("All")) {
for (Profile profile : all) {
List<String> list = userMessages.get(profile.getId());
if (list == null ) {
ArrayList<String> strings = new ArrayList<String>();
strings.add(data);
userMessages.put(profile.getId(), strings);
} else {
list.add(data);
}
}
}
}
}
and my service method is as follows
#Service
public class NoteManager
{
#Autowired AlertsToProfile alertsToProfile;
public void addNote(String type, String message, String category) {
alertsToProfile.setCategoryType(category);
String data = type + "," + message;
alertsToProfile.setDataMessage(data);
alertsToProfile.start();
System.out.println("addNotes is done");
}
But when i call start() method am getting null pointer exception please help me. I am new to spring with thread concept
It pretty obvious: you instantiate your thread directly, as opposed to letting spring create AlertsToProfile and auto wire your instance.
To fix this, create a Runnable around your run() method and embed that into a method, something like this:
public void startThread() {
new Thread(new Runnable() {
#Override
public void run() {
// your code in here
}}).start();
}
you will want to bind the Thread instance to a field in AlertsToProfile in order to avoid leaks and stop the thread when you're done.
I have an enum, say Fruits { Apple, Banana, Cherry }. I want to write a event subsystem for my application so that I can have the following pattern :
class AppleListener implements HasFruitPriceChangeListener<Apple> {
onFruitPriceChange(int newPrice) {
// do stuff
}
}
and a single listener, that can delegate tasks in the following format:
class FruitPriceListener {
public void onPriceChange(EnumMap<Fruits, Integer> pricePoints) {
// for each fruit, throw the event as
// FruitPriceChange.fire(Apple, newPrice);
}
}
Is there a way to do it in the above manner ? I would probably like to use ValueChangeEvent, but creating another 1 event and handler is also fine too. What I do not want to do is have event/class definitions for each item, like AppleFruitPriceChangeEvent, and so on.
You can use the EventBus for this things, which google suggested ( http://www.youtube.com/watch?v=PDuhR18-EdM ) Here how to use it.
Your globl Eventbus
public static SimpleEventBus bus = new SimpleEventBus();
Your change event:
import com.google.gwt.event.shared.GwtEvent;
import eyeweb.client.gwtMessages.JSPollingEntry;
public class EventModified extends GwtEvent<EventModifiedHandler> {
public final static Type<EventModifiedHandler> TYPE = new Type<EventModifiedHandler>();
private final Fruits fruits;
public final JSPollingEntry getPollingMessage(){
return fruits;
}
public EventModified(Fruits fruits) {
this.fruits = fruits;
}
#Override
public com.google.gwt.event.shared.GwtEvent.Type<EventModifiedHandler> getAssociatedType() {
return TYPE;
}
#Override
protected void dispatch(EventModifiedHandler handler) {
handler.onUpdateRecivde(this);
}
}
the handler for the event
package eyeweb.client.eventbus;
import com.google.gwt.event.shared.EventHandler;
public interface EventModifiedHandler extends EventHandler {
public void onUpdateRecivde(EventModified handler);
}
The event when something changes
EventBus.bus.fireEvent(new EventModified(fruite));
and the handler which gets the event
EventBus.bus.addHandler(EventModified .TYPE, new EventModifiedHandler() {
#Override
public void onMessageSend(EventSendData e) {
//... do stuff }
});
Well that sould be all ;)
Regards,
Stefan
So the solution I came up with was:
Create the enum, and associate a GwtEvent.Type with them:
enum Fruits {
Apple, Banana, Cherry;
public GwtEvent.Type getGwtEventType() {
return new GwtEvent.Type();
}
}
Create a new event.
class FruitPriceChangeEvent extends GwtEvent<?> {
private final Fruit fruit;
FruitPriceChangeEvent(Fruit fruitEnum) {
this.fruit = fruitEnum;
}
#Override
public GwtEvent.Type<?> getAssociatedType() {
return fruit.getGwtEventType();
}
// ... other stuff...
}
And then pass it through the whole event handler loop as #Stefan has mentioned. The beauty/hack of this approach is that the SimpleEventBus maintains a HashMap<GwtEvent.Type, List<HasHandlers>> from which to get the events, and everytime you create a new GwtEvent.Type it generates a unique hashcode (check the implementation for more details).
References:
http://grepcode.com/file/repo1.maven.org/maven2/com.google.gwt/gwt-servlet/2.1.1-rc1/com/google/gwt/event/shared/GwtEvent.java?av=f
http://grepcode.com/file/repo1.maven.org/maven2/com.google.gwt/gwt-servlet/2.1.1-rc1/com/google/gwt/event/shared/SimpleEventBus.java?av=f
Im made a sort of autentication on my web application using GWT. So i make these functions in the GWTServiceImpl Class :
public class PageMenuLogin extends FlowPanel {
public PageMenuLogin() {
PageMenuLogin.getService().isSetSession(new AsyncCallback<String>() {
#Override
public void onFailure(Throwable caught) {
InlineLabel err=new InlineLabel();
err.setText("Errore Di Connessione");
PageMenuLogin.this.add(err);
}
#Override
public void onSuccess(String result) {
if(result.compareTo("")==0) {
designLogin();
} else {
designLogout(result);
}
}
});
}
public final void designLogin() {
final InlineLabel menu_err=new InlineLabel("");
menu_err.setStyleName("menu_err");
this.add(menu_err);
Button menu_login_button=new Button("Login");
this.add(menu_login_button);
menu_login_button.addClickHandler(new ClickHandler() {
public void onClick(ClickEvent event) {
getService().checkLogin("nickname", "password", new AsyncCallback<Boolean>() {
#Override
public void onFailure(Throwable caught) {
menu_err.setText("Comunicazione Fallita");
}
#Override
public void onSuccess(Boolean result) {
if (result) {
// I LOAD THE PROFILE PAGE
} else {
menu_err.setText("Username e password non validi");
}
}
});
}
});
}
}
********************************************************************************
public class GWTServiceImpl extends RemoteServiceServlet implements GWTService {
HttpServletRequest request;
HttpSession session;
public String isSetSession() {
this.request = this.getThreadLocalRequest();
this.session=this.request.getSession();
if(this.session.getAttribute("nickname")==null) {
return "";
} else {
return (String)this.session.getAttribute("nickname");
}
}
public boolean checkLogin(String username, String password) {
if("i check on the database if the user exist") {
this.session.setAttribute("nickname", value);
return true;
}
return false;
}
}
On client side, i call the GWTServiceImpl functions (server side), i check the return values and i do some operations.
Is this the right way to work with session on GWT? Any suggestion/tips/helps would be appreciated :)
Thanks for your time!!!
EDIT
New GWTServiceImpl :
public class GWTServiceImpl extends RemoteServiceServlet implements GWTService {
HttpSession session;
public String isSetSession() {
HttpSession session=getThreadLocalRequest().getSession();
if(session.getAttribute("nickname")==null) {
return "";
} else {
return (String)session.getAttribute("nickname");
}
}
public boolean checkLogin(String nickname, String password) {
HttpSession session=getThreadLocalRequest().getSession();
Database mydb=Configuration.getDatabase();
mydb.connetti();
// faccio md5 ed escape
String log_check_user=nickname;
String log_check_pass=password;
// controllo che l'utente esista
ArrayList<String[]> db_result=null;
db_result=mydb.selectQuery("SELECT nickname FROM users WHERE nickname='"+log_check_user+"' AND password='"+log_check_pass+"'");
mydb.disconnetti();
if(!db_result.isEmpty()) {
session.setAttribute("nickname", nickname);
return true;
}
return false;
}
public boolean checkLogout() {
HttpSession session=getThreadLocalRequest().getSession();
session.invalidate();
return true;
}
}
Looks like it should work. I do a lot of work with GWT, although I often forego the use of the RemoteServiceServlet in favour of passing data back and forth via JSON.
A few suggestions, though. When you're calling a method or field within the same class, you don't need to include the this keyword. It doesn't hurt, but tends to make your code longer than it needs to be. Feel free to keep it though, if you find it makes things clearer for you.
Also, unless you've got methods that actually use the request, you don't need to create the request object; you can just do
session = getThreadLocalRequest().getSession();
A final suggestion: Since you're using the session in more than one method, it might be a good idea to initialize it right away; So, instead of initializing it in isSetSession(), you could just write HttpSession session = getThreadLocalRequest().getSession();, or initialize it in the class's constructor. As it stands now, if you happen to call checkLogin() before isSetSession(), you'll get a NullPointerException since session hasn't yet been initialized.