Module jakarta.concurrency

Package jakarta.enterprise.concurrent

Annotation Interface ContextServiceDefinition

@Repeatable(ContextServiceDefinition.List.class)
@Retention(RUNTIME)
@Target(TYPE)
public @interface ContextServiceDefinition

Defines a ContextService to be injected into ContextService injection points including any required Qualifier annotations specified by qualifiers() and registered in JNDI by the container under the JNDI name that is specified in the name() attribute.

Application components can refer to this JNDI name in the lookup attribute of a Resource annotation,

@ContextServiceDefinition(
     name = "java:app/concurrent/MyContext",
     qualifiers = MyQualifier.class,
     propagated = APPLICATION,
     unchanged = TRANSACTION,
     cleared = ALL_REMAINING)
 public class MyServlet extends HttpServlet {
     @Inject
     @MyQualifier
     ConetxtService appContextSvc1;

     @Resource(lookup = "java:app/concurrent/MyContext",
               name = "java:app/concurrent/env/MyContextRef")
     ContextService appContextSvc2;
     ...

 @Qualifier
 @Retention(RetentionPolicy.RUNTIME)
 @Target({ ElementType.FIELD, ElementType.METHOD, ElementType.PARAMETER, ElementType.TYPE })
 public @interface MyQualifier {}
 

Resource environment references in a deployment descriptor can similarly specify the lookup-name,

 <resource-env-ref>
    <resource-env-ref-name>java:app/env/concurrent/MyContextRef</resource-env-ref-name>
    <resource-env-ref-type>jakarta.enterprise.concurrent.ContextService</resource-env-ref-type>
    <lookup-name>java:app/concurrent/MyContext</lookup-name>
 </resource-env-ref>
 

The cleared(), propagated(), and unchanged() attributes enable the application to configure how thread context is applied to tasks and actions that are contextualized by the ContextService. Constants are provided on this class for context types that are defined by the Jakarta EE Concurrency specification. In addition to those constants, a Jakarta EE product provider may choose to accept additional vendor-specific context types. Usage of vendor-specific types will make applications non-portable.

Overlap of the same context type across multiple lists is an error and prevents the ContextService instance from being created. If ALL_REMAINING is not present in any of the lists, it is implicitly appended to the cleared() context types.

You can also define a ContextService with the <context-service> deployment descriptor element. For example,

 <context-service>
    <name>java:app/concurrent/MyContext</name>
    <cleared>Security</cleared>
    <cleared>Transaction</cleared>
    <propagated>Application</propagated>
    <unchanged>Remaining</unchanged>
 </context-service>
 

If a context-service and ContextServiceDefinition have the same name, their attributes are merged to define a single ContextService definition, with each attribute that is specified in the context-service deployment descriptor entry taking precedence over the corresponding attribute of the annotation. If any qualifier elements are specified, the set of qualifier elements replaces the qualifiers attribute of the annotation.

Since:

3.0

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static @interface	ContextServiceDefinition.List	Enables multiple ContextServiceDefinition annotations on the same type.

Field Summary

Fields

Modifier and Type	Field	Description
static final String	ALL_REMAINING	All available thread context types that are not specified elsewhere.
static final String	APPLICATION	Context pertaining to the application component or module, including its Jakarta EE namespace (such as java:comp/env/) and thread context class loader.
static final String	SECURITY	Context that controls the credentials that are associated with the thread, including the caller subject and invocation/RunAs subject.
static final String	TRANSACTION	Context that controls the transaction that is associated with the thread.

Required Element Summary

Required Elements

Modifier and Type	Required Element	Description
String	name	JNDI name of the ContextService instance being defined.

Optional Element Summary

Optional Elements

Modifier and Type	Optional Element	Description
String[]	cleared	Types of context to clear whenever a thread runs the contextual task or action.
String[]	propagated	Types of context to capture from the requesting thread and propagate to a thread that runs the contextual task or action.
Class<?>[]	qualifiers	List of required qualifier annotations.
String[]	unchanged	Types of context that are left alone when a thread runs the contextual task or action.

Field Details

ALL_REMAINING

static final String ALL_REMAINING

All available thread context types that are not specified elsewhere. This includes thread context types from custom ThreadContextProviders that are not specified elsewhere.

For example, to define a ContextService that propagates SECURITY context, leaves TRANSACTION context alone, and clears every other context type:

@ContextServiceDefinition(
     name = "java:module/concurrent/SecurityContext",
     propagated = SECURITY,
     unchanged = TRANSACTION,
     cleared = ALL_REMAINING)
 public class MyServlet extends HttpServlet ...
 

See Also:

• Constant Field Values

APPLICATION

static final String APPLICATION

Context pertaining to the application component or module, including its Jakarta EE namespace (such as java:comp/env/) and thread context class loader.

A cleared application context means that the thread is not associated with any application component and lacks access to the Jakarta EE namespace and thread context class loader of the application.

See Also:

• Constant Field Values

SECURITY

static final String SECURITY

Context that controls the credentials that are associated with the thread, including the caller subject and invocation/RunAs subject.

A cleared security context gives the thread unauthenticated subjects.

See Also:

• Constant Field Values

TRANSACTION

static final String TRANSACTION

Context that controls the transaction that is associated with the thread.

When cleared transaction context is applied to a thread, any global transaction that was previously present there is first suspended such that the contextual task or action can begin and manage, as permitted by the container, its own new jakarta.transaction.UserTransaction. After the contextual task or action completes, the prior transaction is resumed on the thread. This is equivalent to the execution property, ManagedTask.TRANSACTION with a value of ManagedTask.SUSPEND.

The execution property, ManagedTask.TRANSACTION, if specified, takes precedence over the behavior for transaction context that is specified on the resource definition annotations.

Jakarta EE providers need not support the propagation of transactions to other threads and can reject resource definition annotations that include transaction as a propagated context.

See Also:

• Constant Field Values

Element Details

name

String name

JNDI name of the ContextService instance being defined. The JNDI name must be in a valid Jakarta EE namespace, such as,

• java:comp
• java:module
• java:app
• java:global

Returns:

ContextService JNDI name.

qualifiers

Class<?>[] qualifiers

List of required qualifier annotations.

A ContextService injection point with these qualifier annotations injects a bean that is produced by this ContextServiceDefinition.

The default value is an empty list, indicating that this ContextServiceDefinition does not automatically produce bean instances for any injection points.

When the qualifiers list is non-empty, the container creates a ContextService instance and registers an ApplicationScoped bean for it with the specified required qualifiers and required type of ContextService. The life cycle of the bean aligns with the life cycle of the application and the bean is not accessible from outside of the application. Applications must not configure a java:global name if also configuring a non-empty list of qualifiers.

Applications can define their own Producers for ContextService injection points as long as the qualifier annotations on the producer do not conflict with the non-empty qualifiers() list of a ContextServiceDefinition.

Returns:

list of qualifiers.

Since:

3.1

Default:

{}

cleared

String[] cleared

Types of context to clear whenever a thread runs the contextual task or action. The thread's previous context is restored afterward.

Constants are provided on this class for the context types that are defined by the Jakarta EE Concurrency specification.

Returns:

context types to clear.

Default:

{"Transaction"}

propagated

String[] propagated

Types of context to capture from the requesting thread and propagate to a thread that runs the contextual task or action. The captured context is re-established when threads run the contextual task or action, with the respective thread's previous context being restored afterward.

Constants are provided on this class for the context types that are defined by the Jakarta EE Concurrency specification.

Returns:

context types to capture and propagate.

Default:

{"Remaining"}

unchanged

String[] unchanged

Types of context that are left alone when a thread runs the contextual task or action.

For example, with unchanged = TRANSACTION if a transaction is started after a function is contextualized, but before the function is run on the same thread, the transaction will be active in the contextual function:

Consumer<String, Integer> updateDB = contextService.contextualConsumer(fn);

// later, on another thread
tx.begin();
updateDB.accept("java:comp/env/jdbc/ds1");
//...additional transactional work
tx.commit();

Constants are provided on this class for the context types that are defined by the Jakarta EE Concurrency specification.

Returns:

context types to leave unchanged.

Default:

{}