Use a "remote" EJB in Camel routes

Introduction

You have an existing application, let say developed using J2EE, including EJB (Session).
The application is running into a J2EE application server like JBoss, WebSphere or Weblogic.

This application “exposes” EJBs to perform some business services.

Now, you can to use these “remote” EJBs into Camel routes.

Context

We want to “expose” the EJB using WebService.

As for all EJBs, we have two interfaces for our EJB: the local and remote interfaces.
Let assume that we have:

* ejb.MyEjbSession
* ejb.MyEjbSessionHome

We assume that the MyEjbSession EJB provides a businessMethod() method, with a String in argument, and returning a String.

The first thing to do is to define an interface containing the WebService annotation. This interface will define the operations and will be used to generate the WSDL on the fly:


package net.nanthrax.blog.camel;

@WebService(targetNamespace = "http://www.nanthrax.net/blog", name = "MyEjbService")
public interface MyEjbService {

    public String businessService(String message);

}

Now, we can create a bean implementing this interface:


package net.nanthrax.blog.camel;

import ejb.MyEjbSession;

@WebService(serviceName = "myEjbService", targetNamespace = "http://www.nanthrax.net/blog", endpointInterface = "net.nanthrax.blog.camel.MyEjbService")
public class MyEjbServiceImpl implements MyEjbService {

&nbps;   private MyEjbSession proxy = null;

    public String businessService(String message) {
        return proxy.businessMethod(message);
    }

    public void setProxy(MyEjbSession proxy) {
        this.proxy = proxy;
    }

    public MyEjbSession getProxy() {
        return this.proxy;
    }

}

Camel routes

Now, we have a bean that we can use in a route. We use Spring Camel DSL. We also use Spring classes to connect to the J2EE application server and to inject the EJB proxy. In this example, we use JBoss application server:


<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:cxf="http://camel.apache.org/schema/cxf"
xsi:schemaLocation="
http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://camel.apache.org/schema/spring http://camel.apache.org/schema/spring/camel-spring.xsd
http://camel.apache.org/schema/cxf http://camel.apache.org/schema/cxf/camel-cxf.xsd
">

    <bean id="jndiTemplate" class="org.springframework.jndi.JndiTemplate">
    <property name="environment">
      <props>
        <prop key="java.naming.factory.initial">org.jnp.interfaces.NamingContextFactory </prop>
        <prop key="java.naming.provider.url">jnp://host:1099</prop>
      </props>
    </property>
    </bean>

    <bean id="ejbProxy" class="org.springframework.ejb.access.SimpleRemoteStatelessSessionProxyFactoryBean">
        <property name="jndiName" value="ejb/jndi/name/MyEjbSession" />
        <property name="businessInterface" value="ejb.MyEjbSession />
        <property name="homeInterface" value="ejb.MyEjbSessionHome" />
        <property name="refreshHomeOnConnectFailure" value="true" />
        <property name="cacheHome" value="true" />
        <property name="lookupHomeOnStartup" value="false" />
        <property name="resourceRef" value="false" />
        <property name="jndiTemplate" ref="jndiTemplate" />
    </bean>

    <bean id="ejbService" class="net.nanthrax.blog.camel.MyEjbServiceImpl">
        <property name="proxy" ref="ejbProxy"/>
    </bean>

    <import resource="classpath:META-INF/cxf/cxf.xml"/>
    <import resource="classpath:META-INF/cxf/cxf-extension-soap.xml"/>
    <import resource="classpath:META-INF/cxf/cxf-extension-http-jetty.xml"/>

    <cxf:cxfEndpoint id="cxfEndpoint"
serviceClass="net.nanthrax.blog.camel.MyEjbService"
address="http://0.0.0.0:9090/blog/ejb-service/"/>

    <camelContext xmlns="http://camel.apache.org/schema/spring">
        <route>
            <from uri="cxf:bean:assetServiceCxfEndpoint"/>
            <to uri="assetServiceBean"/>
        </route>
    </camelContext>

</beans>

Comments

Post a Comment

Popular posts from this blog

Quarkus and "meta" extension

Quarkus is a great Java framework with a large ecosystem thanks to the extensions . Basically, if using Maven, your pom.xml contains the list of the extensions you want to use, meaning something like this: ... <dependency> <groupId>io.quarkus</groupId> <artifactId>quarkus-grpc</artifactId> </dependency> <dependency> <groupId>io.quarkus</groupId> <artifactId>quarkus-opentelemetry</artifactId> </dependency> ... It can quickly become large, and sometime you can have "conflict" between extensions (for example if you mix in the same dependencies set reactive and non reactive extensions). Quarkus "meta" extension To simplify the dependencies for the extensions you want to use (especially if it's basically the same extensions in all your services), you can create your own "meta" extension. This extension doesn't contain actual code, it "wraps" other exten
Read more

Getting started with Apache Karaf Minho

Image
Apache Karaf Minho Apache Karaf Minho is a new runtime, completely created from scratch. The objectives are: super easy to use and run ligtning fast, including GraalVM support Kubernetes compliant to be easily used on the cloud helping to optimize cloud costs by supporting applications colocation providing turnkey services allowing you to create Minho applications in a minute Minho is composed by: minho-boot is the core of Minho. It contains the runtime launcher and the core services (service registry, lifecycle service, configuration service, ...). minho-* services provided additional functionnalities in the runtime. You can use these services to create your own services, it's also where you will find the services managing sepcific kind of applications, allowing colocation. minho-tooling optionally provide convenient tools to create your own runtime. It includes minho-maven-plugin for instance. In this blog post, we will take a quick tour on A
Read more

Apache Karaf Minho and OpenTelemetry

Image
Telemetry is an important part of a software stack, especially on distributed system (where services call each others). OpenTelemetry is a CNCF project coming from OpenTracing and OpenCensus. It provides API to easily instrument your code and tools to collect and export telemetry data (metrics, logs and traces). Before going into how to use OpenTelemetry with Minho, we have to understand some key concepts: Span is a single building block representing an operation or some unit of work that you want to capture. They are capable of standing on their own, referencing (or following) from other spans, storing metadata, tags, etc. Trace is a visualisation of the life of a request (or series of other operations) that is made up of one or more spans. This collection of spans work together to paint a picture of the overall request, allowing you to easily reconstruct what happened within each span, etc. SpanContext is a wrapper of key values pairs that associates a trace to one or mor
Read more