is it possible to use a CXF ResourceComparator in OpenLiberty or WASLiberty?
http://cxf.apache.org/docs/jax-rs-basics.html#JAX-RSBasics-Customselectionbetweenmultipleresourcesoroperations
Must the cxf dependencies be supplied in the WEB-INF/lib or is enough to modify the apiVisibility of the app? And how can be declared to CXF? with a cxf.xml?
TIA
PacoG
There are multiple ways to use CXF in OpenLiberty/WebSphere Liberty:
* You can use the built-in jaxrs-2.0 feature, or
* You can package the CXF modules you need with your app (or in a shared library associated with your app)
If you use the first approach (jaxrs-2.0 feature), then you will only have the JAX-RS 2.0 APIs available - which does not include CXF ResourceComparators. There are a few IBM-specific APIs that go above and beyond the spec (for example, integration with CDI, security, attachment processing, etc.) - you can find more information on those APIs at:
https://www.ibm.com/support/knowledgecenter/en/SSEQTP_8.5.5/com.ibm.websphere.wlp.doc/ae/twlp_dep_jaxrs.html
If you use the second approach, then you have the full feature set of the CXF modules in your application, but they will not be fully integrated with other Liberty features like the jaxrs-2.0 feature is. For usage instructions, I would suggest the Apache CXF documentation - like the page you referenced in the initial question.
Hope this helps, Andy
Related
I'm trying to get rid of XML in my project.
I already tried to add this:
JAXRSServerFactoryBean sf = new JAXRSServerFactoryBean();
sf.setResourceClasses(CustomerService.class);
sf.setAddress("http://localhost:9000/");
sf.create();
to my Activator class, but my bundle wont start with this.
So, how usually people configuring endpoints?
(Sorry, no code, just some high level insights from my experience/projects)
I use jersey and its integration into the OSGi environment. I.e. org.glassfish.jersey.servlet.ServletContainer to which I register all jax-rs resources. This way, I can use whatever HTTP server implementation is available (for example, jetty) and configure it via the OSGi system environment properties.
For simplicity, I re-register annotated OSGi (declarative) services as singleton resources/endpoints into that ServletContainer.
Maybe, CXF has also a similar approach.
I've found conflicting answers to this question and I've failed to successfully run an example.
Can JAX-RS be implemented using Servlet 3.0 (in particular, Tomcat 7) with annotations, only, without having to implement another Servlet Container?
If no, please explain why the following quote from this book is either, incorrect or I'm interpreting it, wrong.
Because this example deploys within a Java EE application server or
standalone Servlet 3.x container, all we need is an empty web.xml
file. The server will detect that an Application class is within your
WAR and automatically deploy it. (RESTful Java with JAX-RS 2.0, Bill Burke)
To clarify what I don't need help with... I've, successfully, implemented JAX-RS in Tomcat 7 with Jersey using a web.xml, so, I don't need any explanation of how to do so. Also, I'm fully aware that other Java EE/Servlet Containers (TomEE, Glassfish, Jersey, Websphere, etc...) are all JAX-RS aware out of the box. I just need to know if I'm chasing my tail trying to get Tomcat 7 (Servlet 3.0) to work with JAX-RS without adding a Servlet Container and without web.xml entries.
In a Servlet environment, Jersey runs as a servlet or servlet filter. No way around that. So how does it work without declaring it in the web.xml? Two main components to this functionality
Programmatic registration of Servlet components (i.e. servlets and fitlers). You can do a Google search, and you should find some hits of examples.
Servlet pluggability introduced in Servlet 3.x. How it works is you implement a ServletContainerInitializer, list that implementation in a file named javax.servlet.ServletContainerInitializer, and put that file in the META-INF/services directory of the jar. The servlet container should scan jars looking for this file. When it finds on, it sees the implementation, finds the implementation, instantiates it, then calls it onStartup method.
Jersey has such an implementation of the SevletContainerInitializer in the JerseyServletContainerInitializer. This class is located in the jersey-container-servlet jar. So you need this jar for this to work. If you look at this method, this is where you will see the programmatic registration of the ServletContainer (the same one that yo would declare in the web.xml
But that's not all. We still need some way of configuring our application, at the least declare the servlet mapping. That's where the Application class and the #ApplicationPath annotation come in. We would extend the Application class and and annotate the #ApplicationPath("/path") where "path" is the same as the servlet mapping in the web.xml
#ApplicationPath("/api")
public class MyApplication extends Application {}
This is standard JAX-RS. With Jersey normally instead of an Application class, we use a ResourceConfig class (which is a subclass of Application)
#ApplicationPath("/api")
public class MyApplication extends ResourceConfig {
public MyApplication() {
packages("package.to.scan");
}
}
You can see more about Jersey deployment options in a Servlet 3.x environment, here.
It should also be noted, that a Java EE server has the JAX-RS implementation, so we only need to add the javaee-api jar to our application as provided dependency. But in a servlet container, we need to provide our own implementation, Jersey being such an implementation.
If you are using Maven, the main dependency you'll need is this one
<dependency>
<groupId>org.glassfish.jersey.containers</groupId>
<artifactId>jersey-container-servlet</artifactId>
<version>${jersey2.version}</version>
</dependency>
This will pull a bunch of other jars in. You you aren't using Maven, then you can download all the jars here (the JAX-RS 2.0 RI bundle), and put all those into your application.
See Also:
How to use Jersey as JAX-RS implementation without web.xml?
I am using jax-rs for restful service. And I am trying to find out how I can use a contextlistener for webapp ? I am specifically using jax-rs 2.0 . Any suggestions on how to go about it , would be helpful. Thank you.
I'm not sure what linkage problem you have with servlet.jar. It should actually be in your classpath already, since JAX-RS uses it, too.
Also, if you use a framework such as Hibernate (or another JPA implementation for your MySQL database access), you may want to rely on the events that they trigger after insert/update/delete operations: see https://docs.jboss.org/hibernate/orm/4.0/manual/en-US/html/events.html for example.
Just my 2c.
I have a processing application which accepts REST requests and doesn't include a GUI such as a web front-end. Processing is light but the number of requests is quite high (more than 10,000 requests in a second).
I wonder if Restlet + Simple combination is appropriate for this scenario or do I have to use a Java EE edition?
Does anyone have experience with Restlet + Simple combination?
In Restlet, you have the concept of server connectors. This means that you could choose the appropriate connector for your need in a JSE environment (edition jse). It's clear that the default connector isn't suitable for production (it was even not present within org.restlet in the last version 2.3). So you can choose to use the Jetty extension (simply put the extension org.restlet.ext.jetty in your classpath - no impact in your application code) to use it as transport. We use successfully this approach in production (with load balancy in front of this) for one of our application.
If you don't want to handle load balancing, ... by yourself, you could prefer to use an application server to let it handle this.
Hope it helps you,
Thierry
This question is now up for Bounty! First answer that solves this problem wins.
So I've recently discovered that bundles in OSGI are not 100% isolated from each other, especially when your bundles share a common bundle that has a singleton in it, which can result in two unrelated bundles overwritting the singleton. This issue has manifested itself with the CXF libraries. Let me give a detailed example of what is happening:
We have bundle A, B and the shared bundle CXF all in a FuseESB ServiceMix (An osgi platform). CXF's Bus class is a singleton and because of how OSGI has a single classloader per bundle it will share this singleton with every other bundle that uses CXF. So I seem to be unable to create different buses for bundle A and bundle B, which is important that I do because bundle A should be using SSL and bundle B should not be using SSL. This is even more frustrating given that bundle A and bundle B have nothing to do with each other at all other than that they must be deployed together on the same ServiceMix.
Now I've been at this problem for a while now (1-2 months) and I've read up a lot of different solutions. The problem however is that a lot of the solutions require me to have complete control over the source code and in this case I do not. Bundle A that I'm creating is using some proprietary third-party non-osgi library, called Xenara, which uses CXF. For business reasons beyond my control I MUST use this third-party library. Fortunately I do have access to the CXF spring bean file that this library uses.
My guess for solving this problem is that I need to some how make it so that bundle A can use its own personal instance of CXF or at least make it instantiate its CXF Bus that isn't shared with other bundles. Here are the methods I've tried or considered:
I embedded CXF into bundle A but unfortunately the classloader kept fetching CXF from outside of bundle A instead of looking on the classpath. Never figured out how to force it to search for CXF in bundle A first before searching outside of bundle A.
Suggestions were made to make bundle A into a service. I think there were some misunderstandings and people thought that the singleton was in A and not in CXF. Regardless I tried it and it didn't solve the problem. The CXF bus was still shared between bundle A and B.
Override the classloading so that bundle A uses a different classloader for loading the CXF classes. I don't fully understand the logic for this but I'm sure it will be very tricky given that a spring bean is being used to create the CXF bus and http-conduit. See (4) below to get a better idea.
In CXF there is a way to set the CXF bus and http-conduit for a given thread context. I really want to use this solution, but I can't figure out how to translate the CXF bean file into equivalent java code. The CXF spring bean file is provided below. Note I don't have access to the source code using this http-conduit, which is why I haven't used examples show in this link here at "Using Java Code" because I don't have access to the SOAPService, the wsdl, etc...
<bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
<property name="systemPropertiesModeName" value="SYSTEM_PROPERTIES_MODE_OVERRIDE" />
<property name="searchSystemEnvironment" value="true" />
<property name="ignoreUnresolvablePlaceholders" value="true" />
</bean>
<cxf:bus>
<cxf:outInterceptors>
<bean class="com.xenara.messaging.security.IdentityAssertingOutInterceptor"
scope="singleton" />
</cxf:outInterceptors>
<cxf:features>
<wsa:addressing xmlns:wsa="http://cxf.apache.org/ws/addressing"/>
</cxf:features>
</cxf:bus>
<http-conf:conduit name="*.http-conduit">
<http-conf:client AllowChunking="false" Connection="Keep-Alive" />
<http-conf:tlsClientParameters disableCNCheck="true" secureSocketProtocol="TLS">
<sec:keyManagers keyPassword="${javax.net.ssl.keyStorePassword}">
<sec:keyStore type="JKS" password="${javax.net.ssl.keyStorePassword}"
file="${javax.net.ssl.keyStore}" />
</sec:keyManagers>
<sec:trustManagers>
<sec:keyStore type="JKS" password="${javax.net.ssl.trustStorePassword}" file="${javax.net.ssl.trustStore}" />
</sec:trustManagers>
<sec:cipherSuitesFilter>
<sec:include>SSL_RSA_WITH_3DES_EDE_CBC_SHA</sec:include>
...
</sec:cipherSuitesFilter>
</http-conf:tlsClientParameters>
</http-conf:conduit>
This sounds like the basic premisse of OSGi to me: isolation is provided, but you can do a lot of what you can in regular OSGi; such as, modify static members of a class, and since you all share that class (A presumably exports it, B and C import it), others will notice.
In most situations, I would advise you to not use static class state, since it is bound to mess something up for other bundles.
In your situation, it seems to me that bundle A is a library that has no real use being shared in the framework. I would package the library inside both of the using bundles, if you need real isolation, and not worry about the overhead too much.
For the record: this situation has nothing to do with Servicemix, it's basic Java: if we're talking about the same class, and someone changes a static property, others will notice. If this situation confuses you, you could read up a bit about the class loading and sharing mechanisms in OSGi.
The problem you are facing is fairly essential and basic. You have a static state in a supporting library CXF, while you still want shared instances of the libraries using CXF. You cannot modify the shared libraries (due to the sheer size), nor can you modify CXF (closed-source?). Let's call these shared libraries Foo and Bar.
Suppose you have the following classes:
CXF#1
Foo#1, using CXF#1
Bar#1, using CXF#1
WebApp#1, using Foo#1 and Bar#1
If I understand correctly, you now want another application to use the same instances of Foo and Bar, without using the same underlying library CXF#1. This amounts to the following situation.
CXF#2
CXF#1
Foo#1, using CXF#1 when called by App#1, using CXF#2 when called by App#2
Bar#1, using CXF#1 when called by App#1, using CXF#2 when called by App#2
WebApp#1, using Foo#1 and Bar#1
WebApp#2, using Foo#1 and Bar#1
This is just not possible; not in OSGi and not in any Java framework. An existing class cannot dynamically bind to another class, making the choice based on the calling Bundle. The only way to do this without modifying the libraries, is to duplicate the supporting libraries:
CXF#2
CXF#1
Foo#1, using CXF#1
Bar#1, using CXF#1
Foo#2, using CXF#2
Bar#2, using CXF#2
WebApp#1, using Foo#1 and Bar#1
WebApp#2, using Foo#2 and Bar#2
Indeed, this is a lot of effort and will explode the number of packages on disk and in memory. If the CXF package can only be used by a single application, the most logical solution is to duplicate the package and embed it everywhere you use it. Yes, this includes any and all libraries the package depends on.
A hacky/risky way to resolve this is as follows. You should be able to decompile the CXF class. This will allow you to modify the class as follows:
class CXF {
[...]
public static CXF getInstance() {
// based on the current Stack frame, determine which instance to return. Remember, the instance should be based on the WebApp bundle (while you still have shared libraries in between!)
}
}
This is not foolproof. Suppose your WebApp starts a callback thread originating from library A. This thread calls CXF.getInstance() -> The getInstance() method has no way of determining which WebApp started the callback thread.
The correct solution is to modify all libraries not to use the Singleton pattern. You can probably hack your way around the problem by implementing a special classloader, but this opens a whole other can of worms.
-- EDIT --
After reading up on CXF, it seems very strange that CXF exposes a Singleton class. The thing is made for OSGi! You are probably better off asking the question on the CXF mailing list; they will know all of the special sugar and reasons for making a singleton instance, and probably already thought about this usecase.