IBM Interconnect 2015. Kevin Sutter STSM.

1. © 2015 IBM Corporation
AAI-2236
Using the New Java Concurrency Utilities
with IBM WebSphere
Kevin Sutter, STSM
WebSphere Java EE Architect

2. Agenda
• Introduction
• Managed services
• Additional APIs
• Additional Resources
1

3. Introduction
2
2003 2006 2008 2012 2013
JSR 236
released as part
of Java EE 7
JSR237 is
merged into
JSR236
JSR236 (Timers)
and JSR237 (Work
Managers) filed
CommonJ API
replaced with
extension of Java SE
concurrency API
JSR 236
restarted
JSR Timeline

4. Introduction
Goals
• Provide easy-to-use support to developers for both simple and
advanced concurrency patterns
• Provide a path to migrate standalone apps using Java SE
Concurrency Utilities (JSR-166) to the Java EE platform with a
consistent API
• Provide an easy-to-understand API for developers to create
applications using concurrency design principles
• Make it easy to add concurrency to existing Java EE
applications
3

5. Introduction
• Extension of the Java SE Concurrency Utilities API
• Addresses long standing tenant of EE app servers that well-
behaved applications should not create threads
• WebSphere (like other application servers) provided other
mechanisms for creating and managing threads, such as
Asynchronous Beans, CommonJ Timer and Work Manager.
• Asynchronous task lifecycle management, monitoring and
notification
• Flexible propagation of common Java EE contexts to tasks
4
Available 4Q2014 via Liberty Repository!

6. Agenda
• Introduction
• Managed services
• Additional APIs
• Summary
• Additional Resources
5

7. Services
Overview
• JSR 236 defines four services to be provided by an application
server
• ManagedExecutorService
• ManagedScheduledExecutorService
• ManagedThreadFactory
• ContextService
• Services are accessed by application via:
• resource injection using @Resource
• JNDI lookup
• default instances
• Configured through vendor-defined properties
6

8. Services
ManagedExecutorService overview
• Provides a familiar API for concurrent processing of tasks in
Java EE
• Extends java.util.concurrent.ExecutorService of
Java SE concurrency API
• Allow execution of asynchronous tasks on server managed
threads
• Tasks must implement either:
– java.lang.Runnable
– java.util.concurrent.Callable
7

9. Services
ManagedExecutorService API
• Supports Java EE context propagation including JNDI naming,
classloader, and security contexts
• Not transactional contexts
• Because the service is managed by the server, calling any of
the lifecycle API methods results in IllegalStateException
• Like Java SE, task(s) submission returns one or more
Future(s). These are used to:
• check for task execution status
• wait for and retrieve task result
• cancel task
8

10. Services
ManagedExecutorService Example
@WebServlet(asyncSupported=true)
public class MyServlet extends HttpServlet {
@Resource ManagedExecutorService managedExecutorService;
protected void doGet(HttpServletRequest request,
HttpServletResponse response {
final AsyncContext asyncContext = request.startAsync();
…
Runnable myTask = new Runnable() {
public void run() {
asyncContext.complete();
}
};
…
Future future = managedExecutorService.submit(myTask);
}
9

11. Services
ManagedScheduledExecutorService overview
• Provides a familiar API for scheduling asynchronous tasks in
Java EE
• Supports Java EE context propagation including JNDI naming,
classloader, and security contexts
• Not transactional contexts
• Used for scheduling tasks to run:
• periodically
• after specified delay
• at some custom schedule
10

12. Services
ManagedScheduledExecutorService API
• Extends both ManagedExecutorService and
java.util.concurrent.ScheduledExecutorService
interfaces
• Like ManagedExecutorService, calling any of the lifecycle
API methods results in IllegalStateException
• In addition to schedule methods inherited from Java SE API,
adds methods to support custom scheduling
• schedule with Trigger interface
11

13. Services
ManagedScheduledExecutorService Trigger API
• Interface implemented by application developer to support
flexible, custom scheduling
• Scheduling rules may be:
• simple: a single, absolute date/time
• complex: calendar logic
• Trigger is submitted along with a task using a schedule
method in ManagedScheduledExecutorService
12

14. Services
ManagedScheduledExecutorService Trigger Example
public class SimpleFixedDateTrigger implements Trigger {
private Date fireTime;
public SimpleFixedDateTrigger(Date triggerDate) {
fireTime = triggerDate;
}
public Date getNextRunTime(LastExecution lastExecutionInfo,
Date taskScheduledTime) {
if(taskScheduledTime.after(fireTime)) return null;
return fireTime;
}
public boolean skipRun(LastExecution lastExecutionInfo,
Date scheduledRunTime) {
return scheduledRunTime.after(fireTime);
}
}
13

15. Services
ManagedThreadFactory overview
• Provides the means for Java EE applications to obtain
container-managed threads
• Supports Java EE context propagation including JNDI naming,
classloader, and security contexts
• Not transactional contexts
14

16. Services
ManagedThreadFactory API
• Extends java.util.concurrent.ThreadFactory
• Same API: Thread.newThread(Runnable)
• Supports Java EE context propagation including JNDI naming,
classloader, and security contexts
• Not transactional contexts
• Threads from factory are:
• contextualized with container context
• required to implement the ManagableThread interface
15

17. Services
ManagedThreadFactory Example
// Create a ThreadPoolExecutor using a ManagedThreadFactory.
@Resource ManagedThreadFactory threadFactory;
public ExecutorService getManagedThreadPool() {
// All threads will be contextualized with the context
// of the creating application component.
return new ThreadPoolExecutor(5, 10, 5, TimeUnit.SECONDS,
new ArrayBlockingQueue<Runnable>(10), threadFactory);
}
16

18. Services
ContextService overview
• Creates dynamic proxy objects
• objects are contextualized with container context upon creation
• object methods execute with that captured context
• Used by the other services to contextualize task and threads
• May be used directly for advanced use cases:
• request contextualization of Trigger methods
• request contextualization of task listener notification methods
• propagate custom contexts
• Execution properties control how contextualization occurs
17

19. Services
ContextService API
• Methods to create contextual proxy objects:
• <T> T createContextualProxy(T instance,
Class<T> intf)
• Object createContextualProxy(Object instance,
Class<?>... Interfaces)
• <T> T createContextualProxy(T instance,
Map<String,String> executionProperties,
Class<T> intf)
• Object createContextualProxy(Object instance,
Map<String,String> executionProperties,
Class<?>... Interfaces)
18

20. Services
ContextService Example
public class MyRunnable implements Runnable {
public void run() {
System.out.println("MyRunnable.run with Java EE Context");
}
}
@Resource ThreadFactory threadFactory;
@Resource ContextService ctxService;
MyRunnable myRunnableInstance = new MyRunnable();
Runnable rProxy =ctxService.createContextualProxy(
myRunnableInstance, Runnable.class);
ExecutorService exSvc = Executors.newThreadPool(10, threadFactory);
Future future = exSvc.submit(rProxy);
19

21. Agenda
• Introduction
• Managed services
• Additional APIs
• Additional Resources
20

22. Additional APIs
Transaction Management
• Transactions are not propagated to the threads on which tasks
are run
• Application may obtain a UserTransaction from JTA
• Contextual proxy objects can run in the transaction context of
the invoking thread, controlled by the execution property
ManagedTask.TRANSACTION
• default is ManagedTask.SUSPEND
• ManagedTask.USE_TRANSACTION_OF_EXECUTION_THREAD
21

23. Additional APIs
ManagedTaskListener
• Tasks events are emitted to listeners via
ManagedTaskListener methods when tasks are:
• submitted
• unable to start or cancelled
• starting
• completed, either successfully or with exceptions
• Useful for:
• monitoring task progress
• resubmitting failed tasks
• ManagedTaskListener methods execute with unspecified
context by default
22

24. Additional APIs
ManagedTask
• Any task can optionally implement ManagedTask interface
which provides:
• ManagedTaskListener for lifecycle events notification
• task identification
• any desired execution properties
• Other standard execution ManagedTask properties
• IDENTITY_NAME – used to provide a task name
• LONGRUNNING_HINT – hint of task length
• TRANSACTION – controls transaction participation
– SUSPEND
– USE_TRANSACTION_OF_EXECUTION_THREAD
23

25. Additional APIs
ManagedExecutors
• Similar to Executors utility class of Java SE concurrency
package, contain methods for:
• Creating a ManagedTask capable of receiving notifications via
the specified ManagedTaskListener and with any specified
execution properties
• Testing whether current thread is a ManageableThread that has
been marked for shutdown
24

26. Agenda
• Introduction
• Managed services
• Additional APIs
• Additional Resources
25

27. Additional Resources
• JSR236 specification and API docs
• http://jcp.org/en/jsr/detail?id=236
• JSR236 forum
• http://concurrency-ee-spec.java.net
• Java EE 7 API docs
• http://docs.oracle.com/javaee/7/api
26

28. Sampling of Related Sessions…
• AAI-1713A: Introduction to Java EE 7
• Monday, 2-3pm, Mandalay Bay, Reef Ballroom E
• AAI-1641A: Introduction to Web Sockets
• Monday, 5-6pm, Mandalay Bay, Reef Ballroom E
• AAI-1313A: Agile Development Using Java EE 7 with WebSphere Liberty Profile
(LAB)
• Tuesday, 8-10am, Mandalay Bay, South Seas Ballroom D
• AAI-2236A: Using the New Java Concurrency Utilities with IBM WebSphere
• Tuesday, 2-3pm, Mandalay Bay, Reef Ballroom D
• AAI-2235A: OpenJPA and EclipseLink Usage Scenarios Explained
• Wednesday, 5:30-6:30pm, Mandalay Bay, Surf Ballroom A
• AAI-1610A: Configuring IBM WebSphere Application Server for Enterprise
Messaging Needs
• Wednesday, 5:30-6:30pm, Mandalay Bay, Surf Ballroom E
• AAI-3085A: Don’t Wait! Develop Responsive Applications with Java EE7 Instead
• Thursday, 10:30-11:30am, Mandalay Bay, Lagoon L
27

29. Questions?
28

30. Notices and Disclaimers
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