I'm trying to logging some information after save entity with Spring Data Repository, is there anyway?
Thanks!
You can use Annotated repo event handlers.
Just add the #RepositoryEventHandler annotation to your handler class, than in this class implement the handler method with #HandleAfterCreate and #HandleAfterSave annotations.
#RepositoryEventHandler
public class EventHandler {
#HandleAfterCreate
#HandleAfterSave
public void handleAfterCreateOrSave(Entity e) {
// LOG...
}
}
Related
I want to send message from Service A using SignalR when some event occures (for example, message from Service B received).
So hub method needs to be called from some sort of handler, that not constructed using Dependency Injection. How I can do this?
So far, I tried and read about the following things:
I can inject context into Controller and lead it to my handler. I probably can do that, but passing hub context from the top (controller class) to the bottom (handler class) is not the best approach, which adds a lot of dependencies to the classes that should not be aware of this context, so I would like to avoid that.
I can inject my IHubContext in "any" class, but then, the thing is, how to get an instance of that class on my handler?
Add Static method to class with injected context!? Well, that works until you have 1 client because with new client static property is going to be overwritten.
So I cannot imagine, how handler can use dependency injected IHubContext.
Probably, someone did that before and have an example of how to truly inject context into any class.
Thank you in advance and any additional information will be provided, if necessary.
Answer 1
Here is one possible solution. Implement a factory pattern. Create a factory that knows how to create your handler. Inject the IHubContext in the factory. You can use a few approaches that way:
Construct the Handler by passing in the IHubContext
Create a public property in the Handler and set the IHubContext
Create a method in the Handler and pass the IHubContext as a parameter
You can decide whichever approach suits you. Inject that factory in the controller via DI, and get the handler using the factory method. That way you are not exposing the IHubContext. Please see the code below
public interface IHandlerFactory
{
Handler CreateHandler();
}
public class HandlerFactory : IHandlerFactory
{
private IHubContext _hubContext;
public HandlerFactory(IHubContext context)
{
_hubContext = context;
}
public Handler CreateHandler()
{
return new Handler(param1, param2, _context);
}
}
Then in the entry point, controller/service, inject the factory via DI
public class MyController : Controller
{
private Handler _handler;
public MyController(IHandlerFactory factory)
{
_handler = factory.CreateHandler();
}
}
Then you can use that _handler in the other methods. I hope this helps.
Answer 2
Another possible solution is to use IHostedService if it's possible at all for you. Please see a solution to a GitHub issue, provided by David Fowler here, that I think somewhat relevant to your scenario.
We have implemented several custom ORM objects in our webshop implementation that have references (dependencies) to Intershop Product system object.
When a user tries to delete a certain product in back-office, it causes problems because references to that product may still exist in our custom objects. Naturally, deleting a product that is referenced from one of our custom objects generates an exception like this:
java.sql.SQLTransactionRollbackException: ORA-02091: transaction rolled back ORA-02292: integrity constraint (INTERSHOP.A1POSTPAIDPRICE_CO_002) violated - child record found
We have figured that we could solve that by implementing an ORMObjectListener and overriding objectDeleting method to delete all the references before the product actually gets deleted.
Intershop cookbook for ORM layer states:
"Instances must implement the interface ORMObjectListener for a given ORM object type and register at the factory. The listener is called when instances of the given type are created, changed or removed."
(https://support.intershop.com/kb/index.php/Display/2G3270#Cookbook-ORMLayer-Recipe:NotificationofPersistentObjectChanges)
However, we cannot find a cookbook for registering the listener at the factory. What do we need to do to register the listener?
Also, if there is some better way for handling dependencies to system objects on our custom objects during delete event, I'm open to suggestions.
UPDATE:
This is the listener class I have tried with so far:
public class ProductDeleteListener implements ORMObjectListener<ProductPO> {
#Inject
ProductPOFactory productPOFactory;
/** The Constant LOGGER. */
private static final Logger LOGGER = LoggerFactory.getLogger(ProductDeleteListener.class);
public ProductDeleteListener() {
productPOFactory.addObjectListener(this, new AttributeDescription[0]);
}
#Override
public boolean isOldStateNeeded() {
// TODO Auto-generated method stub
return false;
}
#Override
public void objectChanged(ProductPO object, Map<AttributeDescription, Object> previousValues) {
if (LOGGER.isDebugEnabled()) {
LOGGER.debug("PRODUCT LISTENER TEST - CHANGE");
}
}
#Override
public void objectChanging(ProductPO object, Map<AttributeDescription, Object> previousValues) {
// TODO Auto-generated method stub
}
#Override
public void objectCreated(ProductPO object) {
// TODO Auto-generated method stub
}
#Override
public void objectCreating(ProductPO object) {
// TODO Auto-generated method stub
}
#Override
public void objectDeleted(ORMObjectKey objectKey) {
// TODO Auto-generated method stub
}
#Override
public void objectDeleting(ProductPO object) {
if (LOGGER.isDebugEnabled()) {
LOGGER.debug("PRODUCT LISTENER TEST - PRE DELETE");
}
}
}
But it is not working. Nothing gets logged when object changes or gets deleted.
In addition to what Willem Evertse wrote you need to place your registration code in a class that gets instantiated via Intershop Component Framework.
implementation.component:
<components xmlns="http://www.intershop.de/component/2010" scope="global">
<implementation name="ProductDeleteListenerRegistrar"
class="your.fullqualifed.ProductDeleteRegistrar" start="start" stop="stop"></implementation>
instances.component:
<components xmlns="http://www.intershop.de/component/2010"> <instance name="ORMValidator" with="ORMValidator" scope="global"/></components>
You need to write a class, e.g. ProductDeleteRegistrar and provide start method in which you can add registration calls like Willem described. As for stop method you need to safely unregister your object listener. Make sure both methods are declared to be synchronized.
I think registering a listen would be the right approach. Maybe just look out for performance problems.
You are right that there are no examples of this, but here is an example.
Get the factory that you want to receive messages from. In your case, it is ProductPOFactory
ProductPOFactory productFactory = (ProductPOFactory) NamingMgr.getInstance().lookupFactory(ProductPO.class);
productFactory.addObjectListener(new MyProductChangeListener());
MyProductChangeListener needs to extend AbstractORMObjectListener<ProductPO>
and implement the method public void objectDeleting(T object)
Every time a product gets deleted your listener should be called and then you can clean up your custom orm objects. You can have a look at ImageSetDefinitionPOListener as an example
I am trying to introduce a shortcut key(Ctrl+Shift+f) to our customized editor to format the content.
I've implememented the following changes.
Added changes to plugin xml by adding key extension with definition Id/schema/context.
Implemented Action by extending TextEditorAction class as below.
#Override
public void run() {
this.doOperation(ISourceViewer.FORMAT);
}
Implemented one Formatter class by implementing IContentFormatter.
Passed the above Formatter class to our cutsomized sourceVIewConfiguration (extends SourceViewerConfiguration) class by overriding getContentFormatter.
overrided createActions() API inside our customized editor class which extends TextEditor.
For some reason my shortcut key is not working. I put a debug point inside my action class and noticed the controller is not going there when i press on the shortcut key.
I also noticed that the newly created key is not displayed under preferences -> keys list.
Can somebody provide pointers or example to resolve the issue.
plugin.xml entries:
<key
commandId="com.language.javascripteditor.XJSFormatAction"
schemeId="myScheme"
sequence="M1+M2+z"/>
<scheme
id="myScheme"
name="myScheme">
</scheme>
Formatter class:
public class JavaScriptEditorFormatter implements IContentFormatter {
#Override
public void format(IDocument document, IRegion region) {
try {
String content =document.get(region.getOffset(), region.getLength());
String formatted = new JSBeautifier().js_beautify(content,null);
document.replace(region.getOffset(), region.getLength(), formatted);
} catch (BadLocationException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
}
#Override
public IFormattingStrategy getFormattingStrategy(String contentType) {
throw new UnsupportedOperationException();
}
}
Added a new property file for customized schema with the name plugin_customization.ini and with the content as below
org.eclipse.ui/KEY_CONFIGURATION_ID=myScheme
Command section inside plugin.xml
<command
defaultHandler="com.cisco.nm.workflowbuilder.language.javascripteditor.XJSFormatAction"
id="com.language.javascripteditor.XJSFormatAction"
name="%action.label.format.xjs">
</command>
Instead of a handler I have written an Action class. Please let me know if this approach does not work
1.Added contributor class to extension of the existing editor.
2.Created command with an id for format.eg: com.javascript.text.format
3.written Action class with format method
#Override
public void run() {
this.doOperation(ISourceViewer.FORMAT);
}
4. plugin xml entry
<key
commandId="com.javascript.text.format"
schemeId="org.eclipse.ui.defaultAcceleratorConfiguration"
sequence="M1+M2+F"/>
5. Overriden the createActions() .Inside this method instantiated the Action class and setActionDefinitionId.
In the following case,
public class Base {
#Transactional
public void doSave() {
// ...
}
}
public class Inherited extends Base {
public void someMethod() {
super.doSave();
}
#Override
public void doSave() {
super.doSave();
}
}
If I add the #Transactional annotation to Inherited.someMethod, the interceptor gets called without issue.
However, without the annotation on the inherited class, the interceptor does not get involved in the call to the super class from Inherited.someMethod().
Furthermore, calling Inherited.doSave() does not seem to get the interceptor invoked either. I would have expected the annotation on the superclass to be also valid on the subclass. Is this not the expected behaviour?
I am using Apache DeltaSpike for the #Transactional annotation and this is being deployed as a war in an ear (technically as a jar in a war in an ear). However, this may not be relevant as trying with a custom interceptor shows the same behaviour.
This is JBoss EAP 6.3.0 Alpha in case its relevant.
This is expected. Interceptors are only applied if the object is managed. When you you write it this way with inheritence, it's not applied as it's not part of a call stack that CDI is aware of. You would need to inject Base into your class and call Base.doSave
I am researching Prism v2 by going thru the quickstarts. And I have created a WCF service with the following signature:
namespace HelloWorld.Silverlight.Web
{
[ServiceContract(Namespace = "http://helloworld.org/messaging")]
[AspNetCompatibilityRequirements(RequirementsMode =
AspNetCompatibilityRequirementsMode.Allowed)]
public class HelloWorldMessageService
{
private string message = "Hello from WCF";
[OperationContract]
public void UpdateMessage(string message)
{
this.message = message;
}
[OperationContract]
public string GetMessage()
{
return message;
}
}
}
When I add a service reference to this service in my silverlight project it generates an interface and a class:
[System.ServiceModel.ServiceContractAttribute
(Namespace="http://helloworld.org/messaging",
ConfigurationName="Web.Services.HelloWorldMessageService")]
public interface HelloWorldMessageService {
[System.ServiceModel.OperationContractAttribute
(AsyncPattern=true,
Action="http://helloworld.org/messaging/HelloWorldMessageService/UpdateMessage",
ReplyAction="http://helloworld.org/messaging/HelloWorldMessageService/UpdateMessageResponse")]
System.IAsyncResult BeginUpdateMessage(string message, System.AsyncCallback callback, object asyncState);
void EndUpdateMessage(System.IAsyncResult result);
[System.ServiceModel.OperationContractAttribute(AsyncPattern=true, Action="http://helloworld.org/messaging/HelloWorldMessageService/GetMessage", ReplyAction="http://helloworld.org/messaging/HelloWorldMessageService/GetMessageResponse")]
System.IAsyncResult BeginGetMessage(System.AsyncCallback callback, object asyncState);
string EndGetMessage(System.IAsyncResult result);
}
public partial class HelloWorldMessageServiceClient : System.ServiceModel.ClientBase<HelloWorld.Core.Web.Services.HelloWorldMessageService>, HelloWorld.Core.Web.Services.HelloWorldMessageService {
{
// implementation
}
I'm trying to decouple my application by passing around the interface instead of the concrete class. But I'm having difficulty finding examples of how to do this. When I try and call EndGetMessage and then update my UI I get an exception about updating the UI on the wrong thread. How can I update the UI from a background thread?
I tried but I get UnauthorizedAccessException : Invalid cross-thread access.
string messageresult = _service.EndGetMessage(result);
Application.Current.RootVisual.Dispatcher.BeginInvoke(() => this.Message = messageresult );
The exception is thrown by Application.Current.RootVisual.
Here is something I like doing... The service proxy is generated with an interface
HelloWorldClient : IHelloWorld
But the problem is that IHelloWorld does not include the Async versions of the method. So, I create an async interface:
public interface IHelloWorldAsync : IHelloWorld
{
void HelloWorldAsync(...);
event System.EventHandler<HelloWorldEventRgs> HelloWorldCompleted;
}
Then, you can tell the service proxy to implement the interface via partial:
public partial class HelloWorldClient : IHelloWorldAsync {}
Because the HelloWorldClient does, indeed, implement those async methods, this works.
Then, I can just use IHelloWorldAsync everywhere and tell the UnityContainer to use HelloWorldClient for IHelloWorldAsync interfaces.
Ok, I have been messing with this all day and the solution is really much more simple than that. I originally wanted to call the methods on the interface instead of the concreate class. The interface generated by proxy class generator only includes the BeginXXX and EndXXX methods and I was getting an exception when I called EndXXX.
Well, I just finished reading up on System.Threading.Dispatcher and I finally understand how to use it. Dispatcher is a member of any class that inherits from DispatcherObject, which the UI elements do. The Dispatcher operates on the UI thread, which for most WPF applications there is only 1 UI thread. There are exceptions, but I believe you have to do this explicitly so you'll know if you're doing it. Otherwise, you've only got a single UI thread. So it is safe to store a reference to a Dispatcher for use in non-UI classes.
In my case I'm using Prism and my Presenter needs to update the UI (not directly, but it is firing IPropertyChanged.PropertyChanged events). So what I have done is in my Bootstrapper when I set the shell to Application.Current.RootVisual I also store a reference to the Dispatcher like this:
public class Bootstrapper : UnityBootstrapper
{
protected override IModuleCatalog GetModuleCatalog()
{
// setup module catalog
}
protected override DependencyObject CreateShell()
{
// calling Resolve instead of directly initing allows use of dependency injection
Shell shell = Container.Resolve<Shell>();
Application.Current.RootVisual = shell;
Container.RegisterInstance<Dispatcher>(shell.Dispatcher);
return shell;
}
}
Then my presenter has a ctor which accepts IUnityContainer as an argument (using DI) then I can do the following:
_service.BeginGetMessage(new AsyncCallback(GetMessageAsyncComplete), null);
private void GetMessageAsyncComplete(IAsyncResult result)
{
string output = _service.EndGetMessage(result);
Dispatcher dispatcher = _container.Resolve<Dispatcher>();
dispatcher.BeginInvoke(() => this.Message = output);
}
This is sooooo much simpler. I just didn't understand it before.
Ok, so my real problem was how to decouple my dependency upon the proxy class created by my service reference. I was trying to do that by using the interface generated along with the proxy class. Which could have worked fine, but then I would have also had to reference the project which owned the service reference and so it wouldn't be truly decoupled. So here's what I ended up doing. It's a bit of a hack, but it seems to be working, so far.
First here's my interface definition and an adapter class for the custom event handler args generated with my proxy:
using System.ComponentModel;
namespace HelloWorld.Interfaces.Services
{
public class GetMessageCompletedEventArgsAdapter : System.ComponentModel.AsyncCompletedEventArgs
{
private object[] results;
public GetMessageCompletedEventArgsAdapter(object[] results, System.Exception exception, bool cancelled, object userState) :
base(exception, cancelled, userState)
{
this.results = results;
}
public string Result
{
get
{
base.RaiseExceptionIfNecessary();
return ((string)(this.results[0]));
}
}
}
/// <summary>
/// Create a partial class file for the service reference (reference.cs) that assigns
/// this interface to the class - then you can use this reference instead of the
/// one that isn't working
/// </summary>
public interface IMessageServiceClient
{
event System.EventHandler<GetMessageCompletedEventArgsAdapter> GetMessageCompleted;
event System.EventHandler<AsyncCompletedEventArgs> UpdateMessageCompleted;
void GetMessageAsync();
void GetMessageAsync(object userState);
void UpdateMessageAsync(string message);
void UpdateMessageAsync(string message, object userState);
}
}
Then I just needed to create a partial class which extends the proxy class generated by the service reference:
using System;
using HelloWorld.Interfaces.Services;
using System.Collections.Generic;
namespace HelloWorld.Core.Web.Services
{
public partial class HelloWorldMessageServiceClient : IMessageServiceClient
{
#region IMessageServiceClient Members
private event EventHandler<GetMessageCompletedEventArgsAdapter> handler;
private Dictionary<EventHandler<GetMessageCompletedEventArgsAdapter>, EventHandler<GetMessageCompletedEventArgs>> handlerDictionary
= new Dictionary<EventHandler<GetMessageCompletedEventArgsAdapter>, EventHandler<GetMessageCompletedEventArgs>>();
/// <remarks>
/// This is an adapter event which allows us to apply the IMessageServiceClient
/// interface to our MessageServiceClient. This way we can decouple our modules
/// from the implementation
/// </remarks>
event EventHandler<GetMessageCompletedEventArgsAdapter> IMessageServiceClient.GetMessageCompleted
{
add
{
handler += value;
EventHandler<GetMessageCompletedEventArgs> linkedhandler = new EventHandler<GetMessageCompletedEventArgs>(HelloWorldMessageServiceClient_GetMessageCompleted);
this.GetMessageCompleted += linkedhandler;
handlerDictionary.Add(value, linkedhandler);
}
remove
{
handler -= value;
EventHandler<GetMessageCompletedEventArgs> linkedhandler = handlerDictionary[value];
this.GetMessageCompleted -= linkedhandler;
handlerDictionary.Remove(value);
}
}
void HelloWorldMessageServiceClient_GetMessageCompleted(object sender, GetMessageCompletedEventArgs e)
{
if (this.handler == null)
return;
this.handler(sender, new GetMessageCompletedEventArgsAdapter(new object[] { e.Result }, e.Error, e.Cancelled, e.UserState));
}
#endregion
}
}
This is an explicit implementation of the event handler so I can chain together the events. When user registers for my adapter event, I register for the actual event fired. When the event fires I fire my adapter event. So far this "Works On My Machine".
Passing around the interface (once you have instantiated the client) should be as simply as using HelloWorldMessageService instead of the HelloWorldMessageServiceClient class.
In order to update the UI you need to use the Dispatcher object. This lets you provide a delegate that is invoked in the context of the UI thread. See this blog post for some details.
You can make this much simpler still.
The reason the proxy works and your copy of the contract does not is because WCF generates the proxy with code that "Posts" the callback back on the calling thread rather than making the callback on the thread that is executing when the service call returns.
A much simplified, untested, partial implementation to give you the idea of how WCF proxies work looks something like:
{
var state = new
{
CallingThread = SynchronizationContext.Current,
Callback = yourCallback
EndYourMethod = // assign delegate
};
yourService.BeginYourMethod(yourParams, WcfCallback, state);
}
private void WcfCallback(IAsyncResult asyncResult)
{
// Read the result object data to get state
// Call EndYourMethod and block until the finished
state.Context.Post(state.YourCallback, endYourMethodResultValue);
}
The key is the storing of the syncronizationContext and calling the Post method. This will get the callback to occur on the same thread as Begin was called on. It will always work without involving the Dispatcher object provided you call Begin from your UI thread. If you don't then you are back to square one with using the Dispatcher, but the same problem will occur with a WCF proxy.
This link does a good job of explaining how to do this manually:
http://msdn.microsoft.com/en-us/library/dd744834(VS.95).aspx
Just revisiting old posts left unanswered where I finally found an answer. Here's a post I recently wrote that goes into detail about how I finally handled all this:
http://www.developmentalmadness.com/archive/2009/11/04/mvvm-with-prism-101-ndash-part-6-commands.aspx