Tuesday, July 26, 2005

Rules based routing in JBI using Drools in ServiceMix ServiceMix now has rules based routing using the Drools library. Cool beans! The Java semantic module is a little more verbose than it could be; we're working with the Drools community to put together a neater JBI based rule configuration mechanism which is more concise and JBI friendly - but already using the current Drools modules its very useful for adding routing rules into the JBI bus to provide smart routing in your SOA network. Update: thanks to lots of help from the Drools team, we now have a JBI DSL for Drools which massively simplifies the writing of rules for JBI. See the examples for more details. This feature is currently dependent on CVS HEAD of Drools - there'll be a new release real soon hopefully :) 12:31:45 PM    comment []

Setting up a JNDI context using Spring I was surprised I'd never seen someone doing this before - use Spring to create and configure a JNDI context. In ServiceMix we need to work inside a J2EE container such as when we run inside Geronimo to add JBI capability to the Apache J2EE stack. We also need to work embedded inside any Java SE platform or inside, say, Tomcat. So as well as reusing any JNDI context available - such as for JDBC DataSources etc - we need to be able to provide one when running ServiceMix in stand alone mode for use by other JBI components. There are a couple of JNDI implementations around such as the one in Apache Directory (which has lots of dependencies) and simple-jndi - which looks quite good but I couldn't get to work properly with hierarchial namespaces (probably pilot error). But since most things we work with these days tends to use Spring's XML configuration mechanism we kinda wanted to reuse its ability to nicely configure objects using dependency injection as well as having a ton of neat features (like AOP & interceptors, pooling, factory beans, dependencies, declarative transactions etc). Plus once you become proficient in one XML mechanism to configure POJOs, you don't wanna have to use another one just for JNDI. So we enhanced ActiveMQ's default JNDI provider with a fairly simple Spring wrapper implementation and hey presto we can configure JNDI using regular Spring XML configuration. All thats required is to define this jndi.properties on the classpath java.naming.factory.initial = org.servicemix.jbi.jndi.SpringInitialContextFactory Then this jndi.xml can be placed on the classpath and hey presto - you've a configured JNDI context all configured using Spring. <?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd"> <beans>   <bean id="jndi" class="org.servicemix.jbi.jndi.DefaultContext">     <property name="entries">       <map>         <entry key="jdbc/pxe__pm">           <bean class="org.hsqldb.jdbc.jdbcDataSource">             <property name="database" value="jdbc:hsqldb:mem:pxe"/>           </bean>         </entry>       </map>     </property>   </bean> </beans> You can see more discussions and examples here 10:30:22 AM    comment []