Dependency injection is not working

[daviddev]

Hi guy,

I start to be a bit confuse with the dependency injection. I really want to understand how this works.
I try several thinkg and sometime it is working sometimes not.
Basicaly I have an application (i.e. MM) which consists of a set of Message driven beans, beans, and entities that I want to used in another application (i.e. CMS) as a kind of sub-component.
So I do include MM in CMS (the ejb-jar.xml, and persistence.xml file are used to "configurate" MM).
For some reason MM need to know the application (e.g. CMS) that is using it so I used the ejb-jar.xml file and a <env-entry> specification in each of my message driven and other beans to specify this information.
Each bean (message driven or others) in MM has a property (i.e. applicationName) annotated with @Resource and a get and set method to access it.
It seems that the injection of the resource my approach is working only for message-driven bean but not the other beans and I do not understand why.

MM is deploy within CMS on JBOSS with a .ear file which as this structure:

CMS.EAR
 |--META-INF
 | |--application.xml
 |--CMC.jar (message driven and persitence beans)
 | |--META-INF
 | |--ejb-jar.xml
 |--CMejb.jar (entities classes)
 | |--META-INF
 | |--persistence.xml
 |--MMejb.jar (MM message driven beans)
 |--MSMejb.jar (MM entity classes and persistence beans)
 |--CMSweb.war (CMS servlet...)
 |--MMweb.war (MM Servlet ...)

the application.xml in CMS.ear is:

<application>
 <display-name>CMS</display-name>
 <module>
 <ejb>lib/cmsconfiguratorclient.jar</ejb>
 </module>
 <module>
 <ejb>CMC.jar</ejb>
 </module>
 <module>
 <ejb>CMejb.jar</ejb>
 </module>
 <module>
 <web>
 <web-uri>CMSweb.war</web-uri>
 <context-root>CARDWeb</context-root>
 </web>
 </module>

<!-- MM -->

 <module>
 <ejb>MMweb.war</ejb>
 </module>
 <module>
 <ejb>MMejb.jar</ejb>
 </module>
 <module>
 <ejb>MSMejb.jar</ejb>
 </module>

</application>

the ejb-jar.xml in CMC is

<?xml version="1.0" encoding="UTF-8"?>
<ejb-jar version="3.0" xmlns="http://java.sun.com/xml/ns/javaee"
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/ejb-jar_3_0.xsd">

 <display-name>CMS</display-name>
 <enterprise-beans>

 <message-driven >
 <display-name>MessagerReceiver</display-name>
 <ejb-name>MessageReceiver</ejb-name>
 <ejb-class>com.messaging.messagemanager.receiving.MessageReceiver</ejb-class>
 <transaction-type>Container</transaction-type>
 <activation-config>
 <activation-config-property>
 <activation-config-property-name>destinationType</activation-config-property-name>
 <activation-config-property-value>javax.jms.Queue</activation-config-property-value>
 </activation-config-property>
 <activation-config-property>
 <activation-config-property-name>destination</activation-config-property-name>
 <activation-config-property-value>queue/CMS</activation-config-property-value>
 </activation-config-property>
 </activation-config>
 <env-entry>
 <description>The name of the application</description>
 <env-entry-name>com.messaging.messagemanager.receiving.MessageReceiver/applicationName</env-entry-name>
 <env-entry-type>java.lang.String</env-entry-type>
 <env-entry-value>CMS</env-entry-value>
 </env-entry>
 </message-driven>

 <session>
 <ejb-name>IncomingMessageHandler</ejb-name>
 <ejb-class>com.ecebs.multefile.messaging.messagemanager.receiving.IncomingMessageHandler</ejb-class>
 <env-entry>
 <description>The name of the application</description>
 <env-entry-name>com.messaging.messagemanager.receiving.IncomingMessageHandler/applicationName</env-entry-name>
 <env-entry-type>java.lang.String</env-entry-type>
 <env-entry-value>CMS</env-entry-value>
 </env-entry>
 </session>

 <session>
 <ejb-name>MessageStoreManagerBean</ejb-name>
 <ejb-class>com.messaging.messagestoremanager.MessageStoreManagerBean</ejb-class>
 <env-entry>
 <description>The name of the application</description>
 <env-entry-name>com.messaging.messagestoremanager.MessageStoreManagerBean/applicationName</env-entry-name>
 <env-entry-type>java.lang.String</env-entry-type>
 <env-entry-value>CMS</env-entry-value>
 </env-entry>
 <persistence-context-ref>
 <persistence-context-ref-name>messagemanager_em</persistence-context-ref-name>
 <persistence-unit-name>messagemanager</persistence-unit-name>
 </persistence-context-ref>
 </session>


 </enterprise-beans>

</ejb-jar>

all beans from MM are defined here with the same <env-entry>. here I put only few of them to make it short.
when I debug my application and send a mock message to the "MessagerReceiver" the "applicationName" is set with CMS so the dependency injection did work.
When i simulate I use the IncomingMessageHandler bean, the applicationName is not set with the value specified in the ejb-jar.xml (i.e. CMS).

here the code of the incomingMessageHandler bean and MessageReceiver message driven bean:

@Stateless
public class IncomingMessageHandler implements IIncomingMessageHandler{

 //...

 @Resource
 private String applicationName;

 public String getApplicationName() {
 return applicationName;
 }

 public void setApplicationName(String applicationName) {
 this.applicationName = applicationName;
 }

 //...
}

public class MessageReceiver implements MessageListener{
 //...

 @Resource
 private String applicationName;

 public String getApplicationName() {
 return applicationName;
 }

 public void setApplicationName(String applicationName) {
 this.applicationName = applicationName;
 }

 public void onMessage(Message message) {
 //...
 }
 //...

a little help and explaination will be appreciated to understand what is wrong in my code/approach.
Any good references/internet link that could help me to understand the structure of an ear file or how to use ejb-jar.xml and persistence.xml in ear are also welcome.

Thanks a lot

[jaikiran]

<env-entry-name>com.messaging.messagemanager.receiving.IncomingMessageHandler/applicationName</env-entry-name>

Change this to:

<env-entry-name>applicationName</env-entry-name>

The syntax that you used seems to be applicable when a injection-target is used instead of java annotations.

Any good references/internet link that could help me to understand the structure of an ear file or how to use ejb-jar.xml and persistence.xml in ear are also welcome.

Section 16.4.1 of the EJB3 spec has the details about the syntax and some examples.

Having said that, i am surprised that you are seeing a different behaviour for MDBs. Let us know how that change goes.

By the way, which version of JBoss AS do you use?

[daviddev]

Hi,

thanks for answering.

I did try to use only the name of the property within the env-entry definition ass you mentioned but I still have the same problem. Even worth, the message driven bean are not properly initialised. I need to do a look up of the context to get the appropriate value of the application name.

in summary, if i do not include the package tath within the env-entry e.g.

<env-entry-name>applicationName</env-entry-name>

I need to lookup the context to get the application name set in the ejb-jar.xml. here the code in my session of my bean

//...
try {
 Context ctx = new InitialContext();
 Context envContext = (Context) ctx.lookup( "java:comp/env" );
 String appName = (String) envContext.lookup( "applicationName" );
 this.applicationName = appName;

} catch (NamingException e){
 log.debug( "application name not found" );
}

if I include the full package path

<env-entry-name>com.messaging.messagemanager.receiving.IncomingMessageHandler/applicationName</env-entry-name>

I do not need to do a look up within my message driven bean.

However within the other beans the injection does not work.

I am not sure to understand how the injection work

Thanks for you help

[jaikiran]

Which version of JBossAS do you use? Try this against AS 5.1.0

[daviddev]

Thanks for replying.
I am using JBOSS 4.2.3_GA

[jaikiran]

Please try this on JBoss AS 5.1.0 GA