This talk will explore one of the newest API for Java EE 7, the JSR 352, Batch Applications for the Java Platform. Batch processing is found in nearly every industry when you need to execute a non-interactive, bulk-oriented and long running operation task. A few examples are: financial transactions, billing, inventory management, report generation and so on. The JSR 352 specifies a common set of requirements that every batch application usually needs like: checkpointing, parallelization, splitting and logging. It also provides you with a job specification language and several interfaces that allow you to implement your business logic and interact with the batch container. We are going to live code a real life example batch application, starting with a simple task and then evolve it using the advanced API's until we have a full parallel and checkpointing reader-processor-writer batch. By the end of the session, attendees should be able to understand the use cases of the JSR 352, when to apply it and how to develop a full Java EE Batch Application.

1. Java
EE
7
Batch
Processing
in
the
Real
World
Roberto
Cortez
&
Ivan
St.
Ivanov
JavaOne
2014
#CON2818

2. Who
are
we?
Roberto
Cortez
@radcortez
h/p://www.radcortez.com
Freelancer,
Speaker,
RebelLabs
Author,
Blogger
Ivan
St.
Ivanov
@ivan_stefanov
h/p://nosoGskills.com
Architect,
SAP
Labs
Bulgaria,
JBoss
Forge
contributor

3. QuesHons?
As
soon
as
you
have
them!

4. What
is
Batch?
“A
group
of
records
processed
as
a
single
unit,
usually
without
input
from
a
user.”
(from
Google)

5. Why
Batch?
(Computers)
• Make
use
of
idle
resources
• ShiT
the
Hme
of
processing
• Manage
large
repeated
work
easily
• Shared
by
mulHple
users

6. Batch
is
in
our
lives
• By
paying
bills
• On
the
grocery
• In
traffic
• Cooking
food

7. Why
Batch?
(General)
• Efficiency
• Focus
on
a
single
problem
• Avoid
context
switch
• Reduce
costs

8. State
of
the
Art
• Spring
Batch
• IBM
Websphere
• Hadoop
• Java
SE,
Scheduler,
in-­‐house
frameworks

9. The
JSR-­‐352
• Batch
ApplicaHons
for
the
Java
pla]orm
• Heavily
inspired
by
Spring
Batch
• Available
since
Java
EE
7
• Also
designed
for
Java
SE

10. The
JSR-­‐352
Features
• Task
and
Chunk
oriented
processing
• SequenHal
and/or
Parallel
execuHon
• CheckpoinHng
• Workflow
• Stop
and
restart
• ExcepHon
handling

11. Batch
Domain
Language
Job
Operator
Job
Step
Job
Repository
Item
Reader
Item
Processor
Item
Writer
1
*

12. Job
composiYon
*
Job
Step
*
JobInstance
*
*
*
JobExecuYon
StepExecuYon

13. Java
EE
Batch
API

14. Batchlet
DefiniYon
@Named
public
class
MyBatchlet
extends
AbstractBatchlet
{
@Override
public
String
process()
{
System.out.println("Running
inside
a
batchlet");
return
BatchStatus.COMPLETED.toString();
}
}

15. Job
SpecificaYon
Language
<job
id="myFirstBatch">
<step
id="myStep"
>
<batchlet
ref="myBatchlet"/>
</step>
</job>

16. Start
the
Job
JobOperator
jobOperator
=
BatchRunYme.getJobOperator();
Long
execuYonId
=
jobOperator.start("myJob",
new
ProperYes());
JobExecuYon
jobExecuYon
=
jobOperator.getJobExecuYon(execuYonId);

17. Batchlet
• Task
oriented
Batch
Step
• Suitable
for
• Short
execuHons
• Handle
system
resources
• IniHalizaHon
and
Cleanup

18. Chunk
• ETL
style
(Reader,
Processor,
Writer)
• Suitable
for
• Handle
large
amounts
of
data
• Failover
safety
(checkpoint)
• Long
running
applicaHons

19. Chunk
Processing
Step
ItemReader
ItemProcessor
ItemWriter
read()
read()
process(item)
process(item)
write(items)
item
item
item
item
execute()
ExitStatus

20. Defining
Chunk
Step
<step
id="myChunk">
<chunk
checkpoint-­‐policy="item"
item-­‐count="3">
<reader
ref=“myItemReader"/>
<processor
ref=“myItemProcessor"/>
<writer
ref=“myItemWriter"/>
</chunk>
</step>

21. Item
Reader
@Named
public
class
MyItemReader
extends
AbstractItemReader
{
public
Object
readItem()
throws
ExcepYon
{…}
}

22. Item
Processor
@Named
public
class
MyItemProcessor
implements
ItemProcessor
{
public
Object
processItem(Object
item)
throws
ExcepYon
{…}
}

23. Item
Writer
@Named
public
class
MyItemWriter
extends
AbstractItemWriter
{
public
void
writeItems(List<Object>
items)
throws
ExcepYon
{…}
}

24. ExcepYon
Handling
• Job
ExecuHon
Fails
on
ExcepHon
• Possible
to
Skip
or
Retry
ExcepHons
• Applied
to
the
Chunk
• Include
or
Exclude
ExcepHons

25. ExcepYon
Handling
DefiniYon
<chunk
checkpoint-­‐policy="item”
item-­‐count="3"
skip-­‐limit="3"
retry-­‐limit="3">
<reader
ref="myItemReader"/>
<processor
ref="myItemProcessor"/>
<writer
ref="myItemWriter"/>
<skippable-­‐excepYon-­‐classes>
<include
class="java.lang.RunYmeExcepYon"/>
</skippable-­‐excepYon-­‐classes>
<retryable-­‐excepYon-­‐classes>
<exclude
class="java.lang.IllegalArgumentExcepYon"/>
</retryable-­‐excepYon-­‐classes>
</chunk>

26. ParYYon
• Steps
run
on
mulHple
Threads
• One
ParHHon
per
Thread
• Define
ParHHon
Plan
• CheckpoinHng
is
independent
per
Thread

27. ParYYon
DefiniYon
(In
Step)
<parYYon>
<plan
parYYons="2">
<properYes
parYYon="0">
<property
name="start"
value="1"/>
</properYes>
<properYes
parYYon="1">
<property
name="start"
value="11"/>
</properYes>
</plan>
</parYYon>

28. ParYYon
DefiniYon
(In
Step)
<chunk
item-­‐count="3">
<reader
ref="myItemReader">
<properYes>
<property
name="start”
value="#{parYYonPlan['start']}"
/>
</properYes>
</reader>
<processor
ref="myItemProcessor"/>
<writer
ref="myItemWriter"/>
</chunk>

29. Flow
• Sequence
of
ExecuHon
elements
• Execute
together
as
a
unit
• Flows,
Steps,
Decision
and
Split
• Used
to
aggregate
logical
business.

30. Split
• Concurrent
ExecuHon
of
Flows
• Each
Flow
run
on
a
separate
Thread
• Is
not
the
same
as
a
ParHHon
• Can
only
use
Flows

31. Split
and
Flow
DefiniYon
<split
id="mySplit">
<flow
id="flow1">
<step
id="myChunk"
next="myBatchlet”>…</step>
<step
id="myBatchlet">...</step>
</flow>
<flow
id="flow2">
<step
id=”otherChunk"
next=”otherBatchlet”>…</step>
<step
id=”otherBatchlet">...</step>
</flow>
</split>

32. ParYYon
vs
Split
• ParHHon
is
used
at
the
data
level
• Split
is
used
at
the
business
level

33. Decision
• Decide
the
next
TransiHon
• Applied
to
Steps,
Flows
and
Splits
• It’s
almost
like
an
if
/
else
if
• Requires
an
implementaHon

34. Decision
DefiniYon
<step
id=”myStep"
next="myDecider">
<batchlet
ref="myBatchlet”/>
</step>
<decision
id="myDecider"
ref="MyDecider">
<next
on="foo"
to="myFooStep"/>
<next
on="bar"
to="myBarStep"/>
</decision>

35. Decision
@Named
public
class
MyDecider
implements
Decider
{
public
String
decide(StepExecuYon[]
execuYons)
throws
ExcepYon
{…}
}

36. TransiYons
• TransiHon
Elements
define
the
Workflow
• Applied
to
Steps,
Flows
and
Decision
• Next,
Fail,
End,
Stop
• Fail,
End
and
Stop
terminate
a
Job

37. Batch
Exit
Status
• A
Job
and
Steps
has
an
Exit
Status
• Used
to
control
the
Workflow
• STARTING,
STARTED,
STOPPING,
STOPPED,
FAILED,
COMPLETED,
ABANDONED

38. Schedule
a
Job
(By
@Schedule)
@Singleton
public
class
BatchJobRunner
{
@Schedule(dayOfWeek
=
"Sun")
public
void
scheduleJob()
{
JobOperator
jobOperator
=
BatchRunYme.getJobOperator();
jobOperator.start("myJob",
new
ProperYes());
}
}

39. Schedule
a
Job
(By
ManagedScheduledExecutorService)
@Resource(lookup="java:comp/DefaultManagedScheduledExecutorService")
private
ManagedScheduledExecutorService
executor;
public
void
scheduleJob()
{
JobOperator
jobOperator
=
BatchRunYme.getJobOperator();
executor.schedule(
()
-­‐>
jobOperator.start("myJob",
new
ProperYes()),
7,
TimeUnit.DAYS);
}

40. ImplementaYons
• JBatch
IBM
(Glassfish,
JEUS)
• JBeret
(Wildfly)
• Spring
Batch

41. A
Few
Cons
• Lacks
standard
Readers
/
Writers
• No
Generics
• ParHHon
only
supports
a
single
Step
• No
Sync
mode

42. Demo
Time

43. WoW
AucYon
House
• World
of
WacraT
is
MMORPG
• More
than
500
servers
in
US
and
EU
• Each
server
has
2
AucHon
Houses
• Trades
around
70k
items
/
server
/
hour

44. WoW
AucYon
House
• Data
available
to
download
• Let’s
process
the
data
• Extract
metrics
• Share
the
knowledge

45. Live
Code

46. Resources
• JSR-­‐352
SpecificaHon
hips://jcp.org/en/jsr/detail?id=352
• Java
EE
Samples
hips://github.com/javaee-­‐samples
• Wow
AucHon
House
hips://github.com/radcortez/wow-­‐aucHons

47. Thank
you
for
A/ending!
Roberto
Cortez
@radcortez
h/p://www.radcortez.com
Ivan
St.
Ivanov
@ivan_stefanov
h/p://nosoGskills.com