The org.jboss.ejb.EJBDeployer MBean is responsible for the creation of EJB containers. Given an EJB JAR that is ready for deployment, the EJBDeployer will create and initialize the necessary EJB containers, one for each type of EJB. The configurable attributes of the EJBDeployer are:
VerifyDeployments: a boolean flag indicating if the EJB verifier should be run. This validates that the EJBs in a deployment unit conform to the EJB 2.1 specification. Setting this to true is useful for ensuring your deployments are valid.
VerifierVerbose: A boolean that controls the verboseness of any verification failures/warnings that result from the verification process.
StrictVerifier: A boolean that enables/disables strict verification. When strict verification is enable an EJB will deploy only if verifier reports no errors.
CallByValue: a boolean flag that indicates call by value semantics should be used by default.
ValidateDTDs: a boolean flag that indicates if the ejb-jar.xml and jboss.xml descriptors should be validated against their declared DTDs. Setting this to true is useful for ensuring your deployment descriptors are valid.
MetricsEnabled: a boolean flag that controls whether container interceptors marked with an metricsEnabled=true attribute should be included in the configuration. This allows one to define a container interceptor configuration that includes metrics type interceptors that can be toggled on and off.
WebServiceName: The JMX ObjectName string of the web service MBean that provides support for the dynamic class loading of EJB classes.
TransactionManagerServiceName: The JMX ObjectName string of the JTA transaction manager service. This must have an attribute named TransactionManager that returns that javax.transaction.TransactionManager instance.
The deployer contains two central methods: deploy and undeploy. The deploy method takes a URL, which either points to an EJB JAR, or to a directory whose structure is the same as a valid EJB JAR (which is convenient for development purposes). Once a deployment has been made, it can be undeployed by calling undeploy on the same URL. A call to deploy with an already deployed URL will cause an undeploy, followed by deployment of the URL. JBoss has support for full re-deployment of both implementation and interface classes, and will reload any changed classes. This will allow you to develop and update EJBs without ever stopping a running server.
During the deployment of the EJB JAR the EJBDeployer and its associated classes perform three main functions, verify the EJBs, create a container for each unique EJB, initialize the container with the deployment configuration information. We will talk about each function in the following sections.