java batch


Batch Applications for the Java PlatformReza RahmanGlassFish/Java EE [email protected]


The following is intended to outline our general product direction. It is intended for information purposes only, and may not be incorporated into any contract. It is not a commitment to deliver any material, code, or functionality, and should not be relied upon in making purchasing decisions. The development, release, and timing of any features or functionality described for Oracle’s products remains at the sole discretion of Oracle.


Batch Applications for the Java Platform

Standardizes batch processing for Java– Non-interactive, bulk-oriented, long-running

– Computationally intensive

– Sequentially or in parallel

Led by IBM Spring Batch, WebSphere Compute Grid (WCG), z/OS Batch Part of Java EE 7, can be used in Java SE


JBatch Architecture


Batch Chunks


Reader, Processor, Writerpublic interface ItemReader<T> { public void open(Externalizable checkpoint); public T readItem(); public Externalizable checkpointInfo(); public void close();}

public interface ItemProcessor<T, R> { public R processItem(T item);}

public interface ItemWriter<T> { public void open(Externalizable checkpoint); public void writeItems(List<T> items); public Externalizable checkpointInfo(); public void close();}


<step id=”sendStatements”> <chunk reader=”accountReader” processor=”accountProcessor” writer=”emailWriter” item-count=”10” /></step>

Batch Applications for the Java Platform Step Example

@Named(“accountReader")...implements ItemReader... {public Account readItem() { // read account using JPA

@Named(“accountProcessor")...implements ItemProcessor... {Public Statement processItems(Account account) { // read Account, return Statement

@Named(“emailWriter")...implements ItemWriter... {public void writeItems(List<Statements> statements) { // use JavaMail to send email


Checkpointing

For data intensive, long periods of time– Checkpoint/restart is a common design requirement

Basically saves Reader, Writer positions– Naturally fits Chunk oriented steps

– reader.checkpointInfo() and writer.checkpointInf() are called

– The resulting Externalizable data is persisted

– When the Chunk restarts, the reader and writer are initialized with the respective Externalizable data


Reader, Processor, Writerpublic interface ItemReader<T> { public void open(Externalizable checkpoint); public T readItem(); public Externalizable checkpointInfo(); public void close();}

public interface ItemProcessor<T, R> { public R processItem(T item);}

public interface ItemWriter<T> { public void open(Externalizable checkpoint); public void writeItems(List<T> items); public Externalizable checkpointInfo(); public void close();}


Handling Exceptions

<job id=...> <chunk reader...> <skippable-exception-classes> <include class="java.lang.Exception"/> <exclude class="java.io.FileNotFoundException"/> </skippable-exception-classes> <retryable-exception-classes> </retryable-exception-classes> <no-rollback-exception-classes> </no-rollback-exception-classes> </chunk></job>


Partitioned Step

A batch step may run as a partitioned step– A partitioned step runs as multiple instances of the same step definition

across multiple threads, one partition per thread

<step id="step1" > <chunk ...> <partition> <plan partitions=“10" threads="2"/> <reducer .../> </partition> </chunk></step>


Flow and Split

Flow defines a set of steps to be executed as a unit<flow id=”flow-1" next=“{flow, step, decision}-id” > <step id=“flow_1_step_1”> </step> <step id=“flow_1_step_2”> </step></flow>

Split defines a set of flows to be executed in parallel

<split …> <flow …./> <!– each flow runs on a separate thread --> <flow …./></split>


Where to Find Out More

Read the draft spec and API docs at http://java.net/projects/jbatch/ Join [email protected] and send questions and comments GlassFish 4.0

– http://glassfish.java.net/

– http://dlc.sun.com.edgesuite.net/glassfish/4.0/promoted/

Slide Deck– http://www.slideshare.net/reza_rahman


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java batch

Technology

oracle andor

public interface itemwriter

public interface itemprocessor

batch step

sole discretion of oracle

public account readitem

batch applications

public r processitemt