I'm using Spring AOP in my application to log some information at runtime before and after a method call. I have enabled the Spring AOP using annotation #EnableAspectJAutoProxy.
Everything works fine now, however I wonder if there is a way to disable this at runtime. I googled around a lot but came up with nothing.
Related
I would like to add some persistence to save some application data and I feel like I have searched the web for days without any success.
I have found some older links and the eclipse Gemini project. However, I suppose I am too new to understand the implementation or it is just a little dated. Probably, more of my lack of knowledge.
Anyway, is anyone willing to point me to a working example and/or provide me with some assistance offline?
If you want to use H2 with plain JDBC, you won't need the Gemini project. In this case you can wrap the H2.jar with the corresponding JDBC driver in a single bundle (plugin) and implement your db access there.
The Gemini project is for using persistence via JPA, which works with any JDBC capable database.
In either case, be aware that in an OSGi environment like Eclipse RCP, there is one classloader per bundle. This leads to lots of complications. We are using Hibernate as JPA engine within our E4 application and we cannot split the JPA configuration, the JPA engine and the entity beans :-(
We tried using EclipseLink as JPA engine but this doesn't work on all our entities :-(
I found this blog article by Raja Kannappan which briefly explains class loading in OSGi.
You can read more about JPA in The Java EE Tutorials (although JPA is part of Java SE, too).
Hope this helps.
this is a very basic question, and I'm kind of sorry, but I don't seem to be able to get a simple Tapestry-IOC based application to work with the built-in Tapestry JPA module.
The application is not necessarily meant as a web project so the dependencies are just tapestry-ioc and tapestry-jpa for the JPA integration. I used the hibernate-entitymanager before and everything worked fine. But I thought I might rather use the official JPA support of Tapestry.
So what I did was to get the above mentioned dependencies (in Tapestry version 5.3.7) and to write the beginning of a test.
This beginning looks like this
Registry registry = RegistryBuilder.buildAndStartupRegistry(MyModule.class);
EntityManager em = registry.getService(EntityManager.class);
That's all. Because as soon as I try this I get the error that no service would implement the EntityManager interface.
So I added the Tapestry JPA module:
Registry registry = RegistryBuilder.buildAndStartupRegistry(MyModule.class, JpaModule.class);
But then again I get an error that the JpaModule wants to contribute to the ApplicationStatePersistenceStrategySource service which is not present. This service seems to be defined in the TapestryModule so I did
Registry registry = RegistryBuilder.buildAndStartupRegistry(MyModule.class, JpaModule.class, TapestryModule.class);
But this causes an error due to the missing servlet API. So now I get to the point where I would have to define the web environment for Tapestry. But I don't want this, I just wanted to use the JPA integration.
Is this even possible? And if so, how do I do it? Following the documentation at http://tapestry.apache.org/integrating-with-jpa.html does not help in this regard.
Thank you very much for reading, any hint appreciated!
Quick answer -- I could be wrong -- but I thought Tapestry-jpa was intended for using JPA with Tapestry-core (the web framework). I don't think there would be any benefit over plain JPA in your case.
I was looking for the option to profile my APIs. I found Spring AOP is one of the options to profile the methods.
There are two options in Spring AOP to configure and use the aspects:
context:load-time-weaver
aop:aspectj-autoproxy
As per my understanding first option (load-time-weaver) performs weaving at load time without creating any proxy objects. And second option (aspectj-autoproxy) creates proxy objects. Am I correct on this? I believe, creation of proxy objects may hit the performance. wouldn't it?
Which option is best to choose considering better performance? What are the pros and cons of both approaches?
Well, Narendra, first of all there are profilers for profiling software. Maybe there is no need to code anything on your own.
As for your question: I have not idea how to configure Spring because I never use it. I am an AspectJ user. What I do know though, is that Spring AOP always uses proxies (JDK or CGLIB, depending on whether you need to proxy interfaces or classes). This is, as you said, something you probably do not want for profiling. AspectJ, no matter if you use compile or load time weaving, does not need or use proxies and thus should be faster. If you are not already using Spring in your project anyway, I would not touch it just to satisfy your profiling needs. Furthermore, Spring AOP only works for Spring Beans and just offers method interception, not much more. AspectJ is a full-blown AOP implementation and much more powerful. If you are already using Spring, you have a choice of using Spring AOP, AspectJ within Spring or a mixture of both.
I'm trying to write a Java EE 6 application using JPA but without using Hibernate or Spring. I used Netbeans to generate the JPA classes, and I created the tables in Postgres, but I am not able to run DbUnit tests in those JPA classes.
I have tried to base my test unit on the example described in this site: http://www.roseindia.net/testingtools/DbUnit/gettingstarted.shtml but it does not work. I keep getting a "java.lang.NoClassDefFoundError: org/slf4j/LoggerFactory" even though I added slf4j to the project libraries in the IDE.
One thing that I find rather odd about the roseindia site example is that it does not seem to have a caller object for the test object created. I am not sure if a caller object is even needed (complete n00b in JavaEE programming, and kind of lost still).
If you choose to use entities (java classes annotated with #Entity, representing database records), you have to use some JPA provider. You are not restricted to Hibernate, though.
If you're frightened by JPA, your other option is to use plain JDBC. It is far easier to understand, if it's your learning-exercise application, it might be a good idea to try and see how it works. JPA is built on top of JDBC, so when you think you're ready for it, you'll have a solid knowledge base.
So I managed to create a GWT-SpringMVC setup. Wasn't easy (not too many resources), but possible. I even autowired and stuff. It even works :)
However, I can't figure out how to make the GwtTestCase run. Obviously it needs the "server" to be up, and because I use Spring, it needs to pass through the dispatching servlet (no?). But I can't figure out how to connect the two. In production or hosted mode, I got the web.xml and the spring-servlet.xml to configure these things. What can I do for tests?
I thought of ignoring the web part and testing the service directly - but this will deny me the option to automatically tests that everything is "transferable".
(if you have an idea on how to do that, I might ditch the GWTTestCase altogether).
An alternative to GWTTestCase could be the gwt-test-utils framework, which provides a simple integration with Spring (see here for details)