public interface ContextService
java.lang.reflect.Proxy
) with
the addition of context typically associated with applications executing in a
Java™ EE environment.
Examples of such context are classloading, namespace, security, etc.
The proxy objects follow the same rules as defined for the
java.lang.reflect.Proxy
class with the following additions:
createContextualProxy
methods.
hashCode
,
equals
, toString
and all other methods declared in
Object
.
Serializable
.
Serializable
if the proxy instance is serialized.
Modifier and Type | Method and Description |
---|---|
Object |
createContextualProxy(Object instance,
Class<?>... interfaces)
Creates a new contextual object proxy for the input object instance.
|
Object |
createContextualProxy(Object instance,
Map<String,String> executionProperties,
Class<?>... interfaces)
Creates a new contextual object proxy for the input object instance.
|
<T> T |
createContextualProxy(T instance,
Class<T> intf)
Creates a new contextual object proxy for the input object instance.
|
<T> T |
createContextualProxy(T instance,
Map<String,String> executionProperties,
Class<T> intf)
Creates a new contextual object proxy for the input object instance.
|
Map<String,String> |
getExecutionProperties(Object contextualProxy)
Gets the current execution properties on the context proxy instance.
|
<T> T createContextualProxy(T instance, Class<T> intf)
Each method invocation will have the context of the application component instance that created the contextual object proxy.
The contextual object is useful when developing or using Java™ SE threading mechanisms propagating events to other component instances.
If the application component that created the proxy is not started or
deployed, all methods on reflected interfaces may throw an
IllegalStateException
.
For example, to execute a Runnable which is contextualized with the creator's context using a Java™ SE ExecutorService:
public class MyRunnable implements Runnable { public void run() { System.out.println("MyRunnable.run with Java EE Context available."); } } InitialContext ctx = new InitialContext(); ThreadFactory threadFactory = (ThreadFactory) ctx .lookup("java:comp/env/concurrent/ThreadFactory"); ContextService ctxService = (ContextService) ctx .lookup("java:comp/env/concurrent/ContextService"); MyRunnable myRunnableInstance = ...; Runnable rProxy = ctxService.createContextualProxy(myRunnableInstance, Runnable.class); ExecutorService exSvc = Executors.newThreadPool(10, threadFactory); Future f = exSvc.submit(rProxy);
instance
- the instance of the object to proxy.intf
- the interface that the proxy should implement.IllegalArgumentException
- - if the intf
argument
is null or the instance does not implement the specified
interface.Object createContextualProxy(Object instance, Class<?>... interfaces)
This method is similar to <T> T createContextualProxy(T instance, Class<T> intf)
except that this method can be used if the proxy has to support multiple
interfaces.
Example:
public class MyRunnableWork implements Runnable, SomeWorkInterface { public void run() { System.out.println("MyRunnableWork.run with Java EE Context available."); } public void someWorkInterfaceMethod() { ... } } ThreadFactory threadFactory = ...; ContextService ctxService = ...; MyRunnableWork myRunnableWorkInstance = ...; Object proxy = ctxService.createContextualProxy(myRunnableWorkInstance, Runnable.class, SomeWorkInterface.class); // call SomeWorkInterface method on the proxy ((SomeWorkInterface) proxy).someWorkInterfaceMethod(); ExecutorService exSvc = Executors.newThreadPool(10, threadFactory); // submit the proxy as a Runnable to the ExecutorService Future f = exSvc.submit( (Runnable)proxy);
instance
- the instance of the object to proxy.interfaces
- the interfaces that the proxy should implement.IllegalArgumentException
- - if the interfaces
argument is null or the instance does not implement
all the specified interfaces.<T> T createContextualProxy(T instance, Map<String,String> executionProperties, Class<T> intf)
The contextual object is useful when developing or using Java™ SE threading mechanisms propagating events to other component instances.
If the application component that created the proxy is not started or
deployed, all methods on reflected interfaces may throw an
IllegalStateException
.
This method accepts a Map
object which allows the
contextual object creator to define what contexts or behaviors to capture
when creating the contextual object. The specified properties will remain
with the contextual object.
For example, to call a Message Driven Bean (MDB) with the sender's context, but within the MDB's transaction:
public class MyServlet ... { public void doPost() throws NamingException, JMSException { InitialContext ctx = new InitialContext(); // Get the ContextService that only propagates // security context. ContextService ctxSvc = (ContextService) ctx.lookup("java:comp/env/SecurityContext"); // Set any custom context data through execution properties Map<String, String> execProps = new HashMap<>(); execProps.put("vendor_a.security.tokenexpiration", "15000"); // Specify that contextual object should run inside the current // transaction. If we have a failure, we don't want to consume // the message. execProps.put(ManagedTask.TRANSACTION, "USE_TRANSACTION_OF_EXECUTION_THREAD"); ProcessMessage msgProcessor = ctxSvc.createContextualProxy(new MessageProcessor(), execProps, ProcessMessage.class); ConnectionFactory cf = (ConnectionFactory) ctx.lookup("java:comp/env/MyTopicConnectionFactory"); Destination dest = (Destination) ctx.lookup("java:comp/env/MyTopic"); Connection con = cf.createConnection(); Session session = con.createSession(true, Session.AUTO_ACKNOWLEDGE); MessageProducer producer = session.createProducer(dest); Message msg = session.createObjectMessage((Serializable)msgProcessor); producer.send(dest, msg); ... } public class MyMDB ... { public void onMessage(Message msg) { // Get the ProcessMessage contextual object from the message. ObjectMessage omsg = (ObjectMessage)msg; ProcessMessage msgProcessor = (ProcessMessage)omsg.getObject(); // Process the message in the specified context. msgProcessor.processMessage(msg); } } public interface ProcessMessage { public void processMessage(Message msg); } public class MessageProcessor implements ProcessMessage, Serializable { public void processMessage(Message msg) { // Process the message with the application container // context that sent the message. } }
instance
- the instance of the object to proxy.executionProperties
- the properties to use when creating and running the context
object.intf
- the interface that the proxy should implement.IllegalArgumentException
- - if the intf
argument
null or the instance does not implement the specified interface.Object createContextualProxy(Object instance, Map<String,String> executionProperties, Class<?>... interfaces)
This method is similar to <T> T createContextualProxy(T instance, Map<String, String> executionProperties, Class<T> intf)
except that this method can be used if the proxy has to support multiple
interfaces.
instance
- the instance of the object to proxy.executionProperties
- the properties to use when creating and running the context
object.interfaces
- the interfaces that the proxy should implement.IllegalArgumentException
- - if the interfaces
argument is null or the instance does not implement all the specified
interfaces.Map<String,String> getExecutionProperties(Object contextualProxy)
contextualProxy
- the contextual proxy instance to retrieve the execution properties.IllegalArgumentException
- thrown if the input contextualProxy is not a valid
contextual object proxy created with the
createContextualProxy
method.Copyright © 1996-2013, Oracle and/or its affiliates. All Rights Reserved. Use is subject to license terms.