s/scan existing application/scan existing annotations/g
On 09/10/2015 06:07 PM, Jean-Baptiste Onofré wrote:
You get the idea. The purpose is to scan existing application (for JPA 2.0) to add the element in the blueprint XML. The purpose of @jpa annotation is also to generate the persistence XML. For instance, what I have in mind is something like: @jpa(provider="openjpa", dataSource = "my-ds") The plugin will generate META-INF/persistence.xml using this annotation. That's what I have in mind ;) Regards JB On 09/10/2015 06:03 PM, Giuseppe Gerla wrote:Hi JB just to understand better. Your idea is to introduce annotation to allow the plugin to generate xml automatically. So it seems that for JPA (for example) you will not introduce some other annotation, because if you find some class that has @PersistenceContext you can add following row in the blueprint xml <jpa:enable /> and for JTA if you find some class with @Transactional annotation you can add following row in the blueprint xml <tx:enable-annotations /> If this is your idea, I agree to extend the Karaf-Boot functionality with JPA and JTA annotation support, otherwise I will prefere to limit it. Regards Giuseppe 2015-09-10 17:46 GMT+02:00 Jean-Baptiste Onofré <[email protected]>:By the way, we don't duplicate functionality: we just leverage and generate the resources. On 09/10/2015 05:40 PM, Christian Schneider wrote:I am not really enthusiastic about duplicating functionality of cxf or aries. Aries supports a very nice approach for injections, jpa and jta. Why should it make sense to recreate that? Aries blueprint also has annoation support even in two flavors (CDI, custom). How does the new approach interact with this? Instead I propose we create support for such annotations in the respective projects (where they are missing) and concentrate on karaf as a container not an application development framework. By leveraging the existing frameworks we profit from their own development teams. Whatever we recreate will have to be developed by the very few resources of the karaf team. Christian Am 10.09.2015 um 16:53 schrieb Jean-Baptiste Onofré:Hi Guillaume, thanks for your feedback. I fully agree about providing more high level annotations (it's what I do with @jpa, @rest, @soap, @jta annotations). I agree that the current annotations are too low level, and blueprint "oriented". I just move forward a bit with the current codebase, just to illustrate karaf-boot usage in the samples. But again, you are right, and I will create a new annotations set. One of the purpose of karaf-boot annotations is to "abstract" the actual code/artifact that we generate. So, if now we generate blueprint, without changing the karaf-boot annotations, we will be able to generate something else (why not SCR, etc). I agree with a BOM, but I think it's interesting to provide both: - providing a ready to use parent pom allows developers to create a very simple pom.xml where all plugins and dependencies are already defined - for more advanced devs, they can create their own pom.xml starting from the BOM or archetype. Thanks again for your feedback ! Regards JB On 09/10/2015 04:44 PM, Guillaume Nodet wrote:I like the idea. For the annotations, we need to keep really high level. The annotations in the code base right now are much too close to blueprint. I think we need to grab a small enough subset so that the annotations are easy to understand for beginners and without any ambiguities, even at the cost of features. For example, I think we should restrict to constructor injection, so that we don't have any bind / rebind / init methods. We simply need an optional @Destroy. In case the dependencies change at runtime, simply destroy the bean / service and recreate it the dependencies are still met after the change. If blueprint is to be hidden completely, we may find a better alternative in SCR or even Felix Dependency Manager, but it does not matter too much for now. I agree with the idea of using a BOM instead of a parent if possible. I'm not very familiar, but this is less invasive. The real problems will come with the support of higher level annotations for JAXRS, JPA, etc... Not really sure how to handle those yet... 2015-09-09 16:32 GMT+02:00 Jean-Baptiste Onofré <[email protected]>: Hi all,I worked on a prototype about Karaf Boot. Let me give you some backgrounds and discuss about that all together. Why Karaf Boot ? ---------------- When you develop artifacts (bundles) to be deployed in Karaf, you can see that the actual time that you spend on your business code is finally largely less important that all the plumbing effort that you have to do (writing OSGi Activator, or blueprint/scr descriptor, etc). It means that your "go to market" is longer, and we should provide something that allows you to focus on your code. Even if SCR annotations is a very good step forward, some use cases are not so easy to do (JPA, JTA for instance). And anyway, you have to prepare your pom.xml with different plugin and dependency. Moreover, when you have your artifacts, you have to prepare Karaf container, and deploy those artifacts there. Even if it's "container" approach is the most important for me, we can give even more flexibility by providing a way to embed and prepare Karaf in a ready to execute jar/artifact. What is Karaf Boot ? -------------------- Karaf Boot provides four components: * karaf-boot-parent is the Maven parent pom that your project just inherit: that's all ! All plugins, dependencies, etc are described in this parent, you even don't have to define packaging as bundle, standard jar is fine. * karaf-boot (coming with karaf-boot-parent) provides annotations that you use directly in your business code (like @Bean, @Service, @Reference, @Inject, etc): again, your focus on your code, karaf-boot deals with the plumbing. * karaf-boot-maven-plugin (coming with karaf-boot-parent) scan the classes and generate a blueprint XML. For now, I'm using blueprint generation (because we can cover lot of use cases, for instance, I plan to provide @rest annotation that will generate blueprint XML with cxf jaxrs server, etc). * karaf-boot-starter is the module providing a convenient way to embed, configure and bootstrap Karaf. Just to illustrate this, let's take a look on the karaf-boot-sample-simple. The pom.xml is really simple: <?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0"; xmlns:xsi=" http://www.w3.org/2001/XMLSchema-instance"; xsi:schemaLocation=" http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd";> <modelVersion>4.0.0</modelVersion> <parent> <groupId>org.apache.karaf.boot</groupId> <artifactId>karaf-boot-parent</artifactId> <version>1.0.0-SNAPSHOT</version> </parent> <artifactId>karaf-boot-sample-simple</artifactId> <version>1.0.0-SNAPSHOT</version> </project> You can see, the only thing that the developer has to do: define karaf-boot-parent as parent pom. That's all. Now, in the code, you have just one bean that we want to run: package org.apache.karaf.boot.sample.simple; import org.apache.karaf.boot.Bean; import org.apache.karaf.boot.Init; @Bean(id = "simple-bean") public class SimpleBean { @Init public void simple() { System.out.println("Hello world"); } } You can see the @Bean and @Init karaf-boot annotations. The karaf-boot-maven-plugin will generate the blueprint descriptor using this. Current Status -------------- I pushed Karaf Boot structure there: https://github.com/jbonofre/karaf-boot It's a mix of rewrapping of existing code (from aries, pax-exam, etc) and additions. I created the annotations, I'm now working on the karaf-boot-maven-plugin based on Christian's work in aries (I'm actually scanning the boot annotations now, and generating the XML). I will push new changes later today and tomorrow. Open Questions --------------- * For now, I would prefer to be 'artifacts' and 'resources' generator: I think it's better than to depend to a feature running in Karaf, but it's open to discussion. * I'm now generating blueprint. Probably native OSGi or scr generation can make sense. * I'm generating bundles: thanks to the Karaf4 features resolver, as the bundles provide requirements/capabilities metadata, I think it's a good start. However, maybe it's worth to be able to create features, kar, profile. Thoughts ? Thanks, Regards JB -- Jean-Baptiste Onofré [email protected] http://blog.nanthrax.net Talend - http://www.talend.com-- Jean-Baptiste Onofré [email protected] http://blog.nanthrax.net Talend - http://www.talend.com
-- Jean-Baptiste Onofré [email protected] http://blog.nanthrax.net Talend - http://www.talend.com
