The following topics provide reference information about the EJB 3.0 metadata annotations:
The new EJB 3.0 programming model uses the
JDK 5.0 metadata annotations feature in which you create an annotated EJB 3.0 bean file and then use the WebLogic compile tool weblogic.appc
(or its Ant equivalent wlappc
) to compile the bean file into a Java class file and generate the associated EJB artifacts, such as the required EJB interfaces and deployment descriptors.
The following sections provide reference information for the metadata annotations you can specify in the EJB bean file. Some of the annotations are in the javax.ejb
package, and are thus specific to EJBs; others are more common and are used by other Java Platform, Enterprise Edition (Java EE) Version 5 components, and are thus in more generic packages, such as javax.annotation
.
This section provides reference information for the following annotations:
Specifies properties used to configure a message-driven bean in its operational environment. This may include information about message acknowledgement modes, message selectors, expected destination or endpoint types, and so on.
This annotation is used only as a value to the activationConfig
attribute of the @
javax.ejb.MessageDriven
annotation.
Specifies that an exception is an application exception and that it should be reported to the client application directly, or unwrapped.
This annotation can be applied to both checked and unchecked exceptions.
Specifies a dependency or reference to an EJB business or home interface.
You annotate a bean’s instance variable with the @EJB
annotation to specify a dependence on another EJB. WebLogic Server automatically initializes the annotated variable with the reference to the EJB on which it depends; this is also called dependency injection. This initialization occurs before any of the bean’s business methods are invoked and after the bean’s EJBContext
is set.
You can also annotate a setter method in the bean class; in this case WebLogic Server uses the setter method itself when performing dependency injection. This is an alternative to instance variable dependency injection.
If you apply the annotation to a class, the annotation declares the EJB that the bean will look up at runtime.
Whether using variable or setter method injection, WebLogic Server determines the name of the referenced EJB by either the name or data type of the annotated instance variable or setter method parameter. If there is any ambiguity, you should use the beanName
or mappedName
attributes of the @EJB
annotation to explicitly name the dependent EJB.
Specifies an array of @javax.ejb.EJB
annotations.
Specifies the correspondence of a method in the bean class with a createMETHOD
method for an adapted EJB 2.1 EJBHome
or EJBLocalHome
client view.
This annotation is used only in conjunction with stateful session beans, or those that have been annotated with the @javax.ejb.Stateful
class-level annotation,
The return type of a method annotated with the @javax.ejb.Init
annotation must be void
, and its parameter types must be exactly the same as those of the referenced createMETHOD
method or methods.
The @Init annotation is required only for stateful session beans that provide a Remote-Home or LocalHome interface. You must specify the name of the adapted create method of the Home or LocalHome interface, using the value
attribute, if there is any ambiguity.
Specifies the local interface or interfaces of a session bean. The local interface exposes business logic to local clients—those running in the same application as the EJB. It defines the business methods a local client can call.
You are required to specify this annotation if your bean class implements more than a single interface, not including the following:
This annotation applies only to stateless or stateful session beans.
Specifies the local home interface of the bean class.
The local home interface provides methods that local clients—those running in the same application as the EJB—can use to create, remove, and in the case of an entity bean, find instances of the bean. The local home interface also has home methods—business logic that is not specific to a particular bean instance.
This attribute applies only to stateless and stateful session beans.
You typically specify this attribute only if you are going to provide an adapted EJB 2.1 component view of the EJB 3.0 bean. You can also use this annotation with bean classes that have been written to the EJB 2.1 APIs.
Specifies that the Enterprise JavaBean is a message-driven bean.
Specifies the configuration of the message-driven bean in its operational environment. This may include information about message acknowledgement modes, message selectors, expected destination or endpoint types, and so on.
You specify activation configuration information using an Array of
@ javax.ejb.ActivationConfigProperty annotation, specify the property name and value.
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You can also use this attribute to specify the JNDI name of the message destination of this message-driven bean. For example:
specifies that this message-driven bean is associated with a JMS queue, whose JNDI name is
my.Queue and is deployed in the WebLogic Server JNDI tree.
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Specifies the life cycle callback method that signals that the EJB container has just reactivated the bean instance.
This annotation applies only to stateful session beans. Because the EJB container automatically maintains the conversational state of a stateful session bean instance when it is passivated, you do not need to specify this annotation for most stateful session beans. You only need to use this annotation, along with its partner @PrePassivate
, if you want to allow your stateful session bean to maintain the open resources that need to be closed prior to a bean instance’s passivation and then reopened during the bean instance’s activation.
Only one method in the bean class can be annotated with this annotation. If you annotate more than one method with this annotations, the EJB will not deploy.
The method annotated with @PostActivate
must follow these requirements:
This annotation does not have any attributes.
Specifies the life cycle callback method that signals that the EJB container is about to passivate the bean instance.
This annotation applies only to stateful session beans. Because the EJB container automatically maintains the conversational state of a stateful session bean instance when it is passivated, you do not need to specify this annotation for most stateful session beans. You only need to use this annotation, along with its partner @PostActivate
, if you want to allow your stateful session bean to maintain the open resources that need to be closed prior to a bean instance’s passivation and then reopened during the bean instance’s activation.
Only one method in the bean class can be annotated with this annotation. If you annotate more than one method with this annotations, the EJB will not deploy.
The method annotated with @PrePassivate
must follow these requirements:
This annotation does not have any attributes.
Specifies the remote interface or interfaces of a session bean. The remote interface exposes business logic to remote clients—clients running in a separate application from the EJB. It defines the business methods a remote client can call.
This annotation applies only to stateless or stateful session beans.
Specifies the remote home interface of the bean class.
The remote home interface provides methods that remote clients—those running in a separate application from the EJB—can use to create, remove, and find instances of the bean.
This attribute applies only to stateless and stateful session beans.
You typically specify this attribute only if you are going to provide an adapted EJB 2.1 component view of the EJB 3.0 bean. You can also use this annotation with bean classes that have been written to the EJB 2.1 APIs.
Use the @javax.ejb.Remove
annotation to denote a remove method of a stateful session bean.
When the method completes, the EJB container will invoke the method annotated with the @
javax.annotation.PreDestroy
annotation, if any, and then destroy the stateful session bean.
Specifies that the Enterprise JavaBean is a stateful session bean.
You can also use this attribute to specify the JNDI name of this stateful session bean. WebLogic Server uses the value of the
mappedName attribute when creating the bean’s global JNDI name. In particular, the JNDI name will be:
where
name_of_businessInterface is the fully qualified name of the business interface of this session bean.
For example, if you specify
mappedName="bank" and the fully qualified name of the business interface is com.CheckingAccount , then the JNDI of the business interface is bank#com.CheckingAccount .
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Specifies that the Enterprise JavaBean is a stateless session bean.
You can also use this attribute to specify the JNDI name of this stateless session bean. WebLogic Server uses the value of the
mappedName attribute when creating the bean’s global JNDI name. In particular, the JNDI name will be:
where
name_of_businessInterface is the fully qualified name of the business interface of this session bean.
For example, if you specify
mappedName="bank" and the fully qualified name of the business interface is com.CheckingAccount , then the JNDI of the business interface is bank#com.CheckingAccount .
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Specifies the timeout method of the bean class.
This annotation makes it easy to program an EJB timer service in your bean class. The EJB timer service is an EJB-container provided service that allows you to create timers that schedule callbacks to occur when a timer object expires.
Previous to EJB 3.0, your bean class was required to implement javax.ejb.TimedObject
if you wanted to program the timer service. Additionally, your bean class had to include a method with the exact name ejbTimeout
. These requirements are relaxed in Version 3.0 of EJB. You no longer are required to implement the javax.ejb.TimedObject
interface, and you can name your timeout method anything you want, as long as you annotate it with the @Timeout
annotation. You can, however, continue to use the pre-3.0 way of programming the timer service if you want.
For details, see Programming the EJB Timer Service.
This annotation does not have any attributes.
Specifies whether the EJB container invokes an EJB business method within a transaction context.
WARNING: | If you specify this annotation, you are also required to use the @TransactionManagement annotation to specify container-managed transaction demarcation. |
You can specify this annotation on either the bean class, or a particular method of the class that is also a method of the business interface. If specified at the bean class, the annotation applies to all applicable business interface methods of the class. If specified for a particular method, the annotation applies to that method only. If the annotation is specified at both the class and the method level, the method value overrides if the two disagree.
If you do not specify the @TransactionAttribute
annotation in your bean class, and the bean uses container managed transaction demarcation, the semantics of the REQUIRED transaction attribute are assumed.
For details about these values, see the description of the trans-attribute element in the
Container-Managed Transactions Elements table.
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Specifies the transaction management demarcation type of the session bean or message-driven bean.
A transaction is a unit of work that changes application state—whether on disk, in memory or in a database—that, once started, is completed entirely, or not at all. Transactions can be demarcated—started, and ended with a commit or rollback—by the EJB container, by bean code, or by client code. This annotation specifies whether the EJB container or the user-written bean code manages the demarcation of a transaction.
If you do not specify this annotation in your bean class, it is assumed that the bean has container-managed transaction demarcation.
For additional information about transactions, see Transaction Design and Management Options.
This section provides reference information for the following annotations:
Specifies the business method interceptor for either a bean class or an interceptor class.
You can annotate only one method in the bean class or interceptor class with the @AroundInvoke
annotation; the method cannot be a business method of the bean class.
This annotation does not have any attributes.
Specifies that any class-level interceptors should not be invoked for the annotated method. This does not include default interceptors, whose invocation are excluded only with the @ExcludeDefaultInterceptors
annotation.
This annotation does not have any attributes.
Specifies that any defined default interceptors (which can be specified only in the EJB deployment descriptors, and not with annotations) should not be invoked.
If defined at the class-level, the default interceptors are never invoked for any of the bean’s business methods. If defined at the method-level, the default interceptors are never invoked for the particular business method, but they are invoked for all other business methods that do not have the @ExludeDefaultInterceptors
annotation.
This annotation does not include any attributes.
Specifies the interceptor classes that are associated with the bean class or method. An interceptor class is a class—distinct from the bean class itself—whose methods are invoked in response to business method invocations and/or life cycle events on the bean.
The interceptor class can include both an business interceptor method (annotated with the @javax.interceptor.AroundInvoke
annotation) and life cycle callback methods (annotated with the @javax.annotation.PostConstruct
, @javax.annotation.PreDestroy
, @javax.ejb.PostActivate
, and @javax.ejb.PrePassivate
annotations).
Any number of interceptor classes may be defined for a bean class. If more than one interceptor class is defined, they are invoked in the order they are specified in the annotation.
If the annotation is specified at the class-level, the interceptors apply to all business methods of the EJB. If specified at the method-level, the interceptors apply to just that method. You can specify the same interceptor class to more than one method of the bean class. By default, method-level interceptors are invoked after all applicable interceptors (default interceptors, class-level interceptors, and so on).
This section provides reference information about the following annotations:
Specifies a dependency on a container-managed EntityManager
persistence context.
You use this annotation to interact with a 3.0 entity bean, typically by performing dependency injection into an EntityManager
instance.
The EntityManager
interface defines the methods that are used to interact with the persistence context. A persistence context is a set of entity instances; an entity is a lightweight persistent domain object. The EntityManager
API is used to create and remove persistent entity instances, to find entities by their primary key, and to query over entities.
If you specify a value for this attribute that is the same as the name of a persistence unit in the
persistence.xml file, the EJB container automatically deploys the persistence unit and sets its JNDI name to its persistence unit name. Similarly, if you do not specify this attribute, but the name of the variable into which you are injecting the persistence context information is the same as the name of a persistence unit in the persistence.xml file, then the EJB container again automatically deploys the persistence unit with its JNDI name equal to its unit name.
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Specifies an array of @javax.persistence.PersistencContext
annotations.
Specifies the array of |
Specifies a dependency on an EntityManagerFactory
object.
You use this annotation to interact with a 3.0 entity bean, typically by performing dependency injection into an EntityManagerFactory
instance. You can then use the EntityManagerFactory
to create one or more EntityManager
instances. This annotation is similar to the @PersistenceContext
annotation, except that it gives you more control over the life of the EntityManager
because you create and destroy it yourself, rather than let the EJB container do it for you.
The EntityManager
interface defines the methods that are used to interact with the persistence context. A persistence context is a set of entity instances; an entity is a lightweight persistent domain object. The EntityManager
API is used to create and remove persistent entity instances, to find entities by their primary key, and to query over entities.
Refers to the name of the persistence unit as defined in the
persistence.xml file. This file is an XML file, located in the META-INF directory of the EJB JAR file, that specifies the database used with the entity beans and specifies the default behavior of the EntityManager .
If you set this attribute, the EJB container automatically deploys the referenced persistence unit and sets its JNDI name to its persistence unit name. Similarly, if you do not specify this attribute, but the name of the variable into which you are injecting the persistence context information is the same as the name of a persistence unit in the
persistence.xml file, then the EJB container again automatically deploys the persistence unit with its JNDI name equal to its unit name.
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Specifies an array of @javax.persistence.PersistenceUnit
annotations.
Specifies the array of |
This section provides reference information about the following annotations:
Specifies the life cycle callback method that the EJB container should execute before the first business method invocation and after dependency injection is done to perform any initialization.
You may specify a @PostConstruct
method in any bean class that includes dependency injection.
Only one method in the bean class can be annotated with this annotation. If you annotate more than one method with this annotations, the EJB will not deploy.
The method annotated with @PostConstruct
must follow these requirements:
This annotation does not have any attributes.
Specifies the life cycle callback method that signals that the bean class instance is about to be destroyed by the EJB container. You typically apply this annotation to methods that release resources that the bean class has been holding.
Only one method in the bean class can be annotated with this annotation. If you annotate more than one method with this annotations, the EJB will not deploy.
The method annotated with @PreDestroy
must follow these requirements:
This annotation does not have any attributes.
Specifies a dependence on an external resource, such as a JDBC data source or a JMS destination or connection factory.
If you specify the annotation on a field or method, the EJB container injects an instance of the requested resource into the bean when the bean is initialized. If you apply the annotation to a class, the annotation declares a resource that the bean will look up at runtime.
If you apply the
@Resource annotation to a field, the default value of the name attribute is the field name, qualified by the class name. If you apply it to a method, the default value is the JavaBeans property name corresponding to the method, qualified by the class name. If you apply the annotation to class, there is no default value and thus you are required to specify the attribute.
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If you apply the
@Resource annotation to a field, the default value of the type attribute is the type of the field. If you apply it to a method, the default is the type of the JavaBeans property. If you apply it to a class, there is no default value and thus you are required to specify this attribute.
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Specifies an array of @Resource
annotations.
This section provides reference information about the following annotations:
Defines the security roles that will be used in the EJB.
You typically use this annotation to define roles that can be tested from within the methods of the annotated class, such as using the isUserInRole
method. You can also use the annotation to explicitly declare roles that are implicitly declared if you use the @RolesAllowed
annotation on the class or a method of the class.
You create security roles in WebLogic Server using the Administration Console. For details, see Manage Security Roles.
Specifies that no security role is allowed to access the annotated method, or in other words, the method is excluded from execution in the EJB container.
This annotation does not have any attributes.
Specifies that all security roles currently defined for WebLogic Server are allowed to access the annotated method.
This annotation does not have any attributes.
Specifies the list of security roles that are allowed to access methods in the EJB.
If you specify it at the class-level, then it applies to all methods in the bean class. If you specify it at the method-level, then it only applies to that method. If you specify the annotation at both the class- and method-level, the method value overrides the class value.
You create security roles in WebLogic Server using the Administration Console. For details, see Manage Security Roles.
Specifies the security role which actually executes the EJB in the EJB container.
The security role must exist in the WebLogic Server security realm and map to a user or group. For details, see Manage Security Roles.
This section provides reference information for the following WebLogic Kodo Annotations:
Note: | The annotations descried in this section are overridden if the comparable configuration is defined in the weblogic-ejb-jar.xml deployment descriptor. For more information, see
“weblogic-ejb-jar.xml Deployment Descriptor Reference” in Programming WebLogic Enterprise JavaBeans. |
Target: Class (Stateful session EJBs only)
Flag that specifies whether an instance can be removed during a transaction.
Note: | This annotation is overridden by the allow-remove-during-transaction element in the weblogic-ejb-jar.xml deployment descriptor. For more information, see
“weblogic-ejb-jar.xml Deployment Descriptor Reference” in Programming WebLogic Enterprise JavaBeans. |
Target: Class (Stateful or stateless sessions EJBs only)
Flag that specifies whether parameters are copied—or passed by reference—regardless of whether the EJB is called remotely or from within the same EAR.
Note: | Method parameters are always passed by value when an EJB is called remotely. This annotation is overridden by the enable-call-by-reference element in the weblogic-ejb-jar.xml deployment descriptor. For more information, see
“weblogic-ejb-jar.xml Deployment Descriptor Reference” in Programming WebLogic Enterprise JavaBeans. |
Specifies that WebLogic Server should disable the warning message whose ID is specified.
Note: | This annotation is overridden by the disable-warning element in the weblogic-ejb-jar.xml deployment descriptor. For more information, see
“weblogic-ejb-jar.xml Deployment Descriptor Reference” in Programming WebLogic Enterprise JavaBeans. |
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Maps EJB reference name to its JNDI name.
Specifies an EJB that is written in such a way that repeated calls to the same method with the same arguments has exactly the same effect as a single call. This allows the failover handler to retry a failed call without knowing whether the call actually compiled on the failed server. When you enable idempotent for a method, the EJB stub can automatically recover from any failure as long as it can reach another server hosting the EJB.
Note: | This annotation is overridden by the idempotent-method and retry-methods-on-rollback elements in the weblogic-ejb-jar.xml deployment descriptor. For more information, see
“weblogic-ejb-jar.xml Deployment Descriptor Reference” in Programming WebLogic Enterprise JavaBeans. |
Specifies a client ID for the MDB when it connects to a JMS destination. Required for durable subscriptions to JMS topics.
If you specify the connection factory that the MDB uses in weblogic.javaee.MessageDestinationConfiguration, the client ID can be defined in the ClientID
element of the associated JMSConnectionFactory
element in config.xml
.
If JMSConnectionFactory
in config.xml
does not specify a ClientID
, or if you use the default connection factory, (you do not specify weblogic.javaee.MessageDestinationConfiguration) the MDB uses the jms-client-id
value as its client id.
Note: | This annotation is overridden by the jms-client-id element in the weblogic-ejb-jar.xml deployment descriptor. For more information, see
“weblogic-ejb-jar.xml Deployment Descriptor Reference” in Programming WebLogic Enterprise JavaBeans. |
Target: Class (Stateful or stateless session EJBs only)
Specifies the JNDI name of an actual EJB, resource, or reference available in WebLogic Server. This annotation is valid on the remote interface and the implementation class, if there is only one remote interface.
Notes: | Assigning a JNDI name to a bean is not recommended. Global JNDI names generate heavy multicast traffic during clustered server startup. See “Using EJB Links” in “Implementing Enterprise Java Beans” in Programming WebLogic Enterprise JavaBeans for the better practice. |
Note: | If you have an EAR library that contains EJBs, you cannot deploy multiple applications that reference the library because attempting to do so will result in a JNDI name conflict. This is because global JNDI name cannot be set for individual EJBs in EAR libraries; it can only be set for an entire library. |
Note: | This annotation is overridden by the jndi-name element in the weblogic-ejb-jar.xml deployment descriptor. For more information, see
“weblogic-ejb-jar.xml Deployment Descriptor Reference” in Programming WebLogic Enterprise JavaBeans. |
Target: Class (Message-driven EJBs only)
Specifies the JNDI name of the JMS Connection Factory that a message-driven EJB looks up to create its queues and topics. See “Configuring MDBs for Destinations” on page 7-18 and “How to Set connection-factory-jndi-name” on page 7-21.
Note: | This annotation is overridden by the connection-factory-jndi-name element in the weblogic-ejb-jar.xml deployment descriptor. For more information, see
“weblogic-ejb-jar.xml Deployment Descriptor Reference” in Programming WebLogic Enterprise JavaBeans. |
Method-level transaction isolation settings for an EJB.
Note: | This annotation is overridden by the trans-timeout-seconds element in the weblogic-ejb-jar.xml deployment descriptor. For more information, see
“weblogic-ejb-jar.xml Deployment Descriptor Reference” in Programming WebLogic Enterprise JavaBeans. |
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Defines the timeout for transactions in seconds.